ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • evolution  (102)
  • Springer  (102)
  • American Meteorological Society
  • 1995-1999  (44)
  • 1990-1994  (58)
  • 1940-1944
  • 1998  (44)
  • 1991  (30)
  • 1990  (28)
  • 1941
Collection
Publisher
Years
  • 1995-1999  (44)
  • 1990-1994  (58)
  • 1940-1944
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 57 (1990), S. 143-150 
    ISSN: 1570-7458
    Keywords: Bruchidae ; Callosobruchus maculatus ; competition ; development ; evolution ; fecundity ; growth rates ; host preferences ; life tables ; mortality ; natural selection ; net reproductive rate ; oviposition traits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Le taux partiel de reproduction nette (R inf0 sup* ) dépend de l'espèce de la plante sur laquelle les œufs sont pondus et du nombre de larves entrant dans la graine. La survie larvaire est réduite par 1/(le nombre de larves par graine) parce qu'une seule larve se développe dans une graine. La fécondité n'est pas modifiée par la compétition subie par les larves, la mortalité larvaire a l'effet le plus important sur R inf0 sup* . Les femelles éliminent ou réduisent la compétition larvaire en dispersant leurs œufs uniformément et font si peu d'erreurs avec une hyperdispersion que l'évolution d'un comportement plus précis n'accroîtrait R inf0 sup* que de 4% au maximum. Des femelles retournant à une distribution des œufs au hasard provoqueraient une réduction de R inf0 sup* de 25% au moins. Les légumineuses généralement cultivées dans l'Inde du Sud sont des hôtes acceptables quand elles sont présentées seules. Le choix des femelles entre 2 hôtes élève R inf0 sup* de 30% ou plus par rapport à une distribution au hasard. Les préférences les plus nettes concernent des combinaisons présentant la plus grande différence de R inf0 sup* . Les femelles qui hyperdispersent leurs œufs, choisissent leurs hôtes et évitent les pertes par compétition en empêchant que les œufs ne donnent plus de descendants que ne le ferait une ponte au hasard. Les particularités de la ponte sont variables et héritables. Les lignées se sélectionnent bien, en fonction de la dispersion de leurs œufs sur les graines, de la discrimination des plantes hôtes, et de la modulation de leur taux de ponte. La sélection naturelle maintient ces particularités du comportement d'une façon sédentaire.
    Notes: Abstract The deposition of eggs by this strain of Callosobruchus maculatus (Fab.) (Bruchidae: Coleoptera) departs from randomness in three ways; eggs are uniformly dispersed, oviposition rates drop when beans begin to carry 2 or more eggs, and there are sharp host preferences. Using random egg placement for the unspecialized condition, these traits are evaluated for their effect on a female's contributions of offspring to the next generation (R0, the net reproductive rate). The major increases in R0 result from females dispersing eggs so uniformly that larval competition is either reduced or eliminated. Females reduce their oviposition rate when the larva from an egg added to a bean is almost certain to die in competitive encounters. Host preferences and larval survival in a host are positively associated with the abundance of the host in South India. The three oviposition traits act together to give and R0 that is 25–50% than that of eggs placed at random. These traits are known to be variable and heritable, hence, the conditions necessary for natural selection are statisfied.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta biotheoretica 46 (1998), S. 141-156 
    ISSN: 1572-8358
    Keywords: locomotion ; Squamata ; lizards ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In lower quadrupedal vertebrates locomotor efficiency seems to result from the associate movements of the axial and appendicular systems, which are totally independent in structure and embryological origin. The curvature of the trunk, produced by a standing wave, magnifies the propulsive action of the limbs. In intermediate forms, the association of an elongate trunk with limbs reduced in size brings about functional consequences which may be noticeably diverse according to the degree of trunk elongation and limb reduction. According to environmental constraints, animals search for better locomotor efficiency, which implies the maintenance or breakage of this association of both locomotor systems. In some cases, limb action on the ground is added to the axial wave action through a perfect mutual adjustment of rhythmic activity, until mechanical inefficiency of the limbs is reached by possible loss of contact with the ground. In other cases, the limbs dragged on the ground during the stance phase act against the axial action or, on the contrary, are inhibited by the axial system. A review of available data tries to contribute to an understanding of the respective roles of both systems in the transition to limblessness.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 60 (1991), S. 173-182 
    ISSN: 1570-7458
    Keywords: Genetics ; evolution ; host adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract When populations are exposed to different environments, evolutionary processes can lead either to genetically differentiated strains or to the appearance of increased generalism at the individual level. For evolution to occur, genetic variability in performance in different environments is required. Here, intraspecific genetic variation across environments was estimated in the flour beetle Tribolium castaneum (Herbst) by comparing the responses of two strains of T. castaneum to different flour types. Replicated groups from each strain were allowed to develop on either the standard whole wheat medium or on one of four novel flours (wheat, rice, corn and oat). In several of the novel flours, clear differences in mean development time or population size of one or both strains were seen relative to performance in the standard medium. Moreover, the strains differed significantly in their phenotypic responses to the flours. One strain did particularly poorly on oat flour. Reduced oviposition, reduced larval survivorship and increased larval cannibalism were examined as possible causes of the low productivity on oat flour. These three factors accounted for about 70% of the reduction in population size when this strain oviposited and developed in oat flour. The difference between these two outbred strains in response to these five flours suggests that genetic variation in resource use is present within T. castaneum and may also be present within strains and natural populations in grain storage facilities. Such variation would permit an evolutionary response to selection in multiple environments (flours). This process has agricultural implications when several types of grain are stored in a single location because it could eventually lead to the evolution of highly generalized populations of T. castaneum, an important pest of stored products.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 46 (1990), S. 1106-1117 
    ISSN: 1420-9071
    Keywords: Genetic code ; eucaryotic cell ; evolution ; code ambiguity ; code universality ; convergence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This article is a review of the rules used by eucaryotic cells to translate a nuclear messenger RNA into a polypeptide chain. The recent observation that these rules are not identical in two species of a same phylum indicates that they have changed during the course of evolution. Possible scenarios for such changes are presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 11 (1998), S. 277-295 
    ISSN: 1572-8773
    Keywords: evolution ; classification ; EF-hand ; domain ; homology ; chimera ; congruence ; gene duplication ; gene fusion ; eukaryote ; dendrogram ; calmodulin ; troponin C ; light chain of myosin ; S100 ; parvalbumin ; calcineurin ; recoverin ; calpain ; sorcin ; diacylglycerol ; calbindin ; aequorin ; phospholipase C ; BM-40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Forty-five distinct subfamilies of EF-hand proteins have been identified. They contain from two to eight EF-hands that are recognizable by amino acid sequence as being statistically similar to other EF-hand domains. All proteins within one subfamily are congruent to one another, i.e. the dendrogram computed from one of the EF-hand domains is similar, within statistical error, to the dendrogram computed from another(s) domain. Thirteen subfamilies - including Calmodulin, Troponin C, Essential light chain, Regulatory light chain - referred to collectively as CTER, are congruent with one another. They appear to have evolved from a single ur-domain by two cycles of gene duplication and fusion. The subfamilies of CTER subsequently evolved by gene duplications and speciations. The remaining 32 subfamilies do not show such general patterns of congruence; however, some - such as S100, intestinal calcium binding protein (calbindin 9kd), and trichohylin - do not form congruent clusters of subfamilies. Nearly all of the domains 1, 3, 5, and 7 are most similar to other ODD domains. Correspondingly the EVEN numbered domains of all 45 subfamilies most closely resemble EVEN domains of other subfamilies. Many sequence and chem-ical characteristics do not show systemic trends by subfamily or species of host organisms; such homoplasy is widespread. Eighteen of the subfamilies are heterochimeric; in addition to multiple EF-hands they contain domains of other evolutionary origins.© Kluwer Academic Publishers
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal for general philosophy of science 21 (1990), S. 231-257 
    ISSN: 1572-8587
    Keywords: basic rules ; change ; discipline-neutral ; evolution ; analogy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Philosophy , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Summary A small step is made in the direction of defining some general basic rules which can serve as a framework for research in several fields of the social sciences. The method of working with analogies asks for a more accurate approach. Starting from the concept of evolution in the form of a basic rule another basic rule is formulated. This rule shows what are the most important factors in long term developments and what types of development one can expect.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal for general philosophy of science 22 (1991), S. 133-141 
    ISSN: 1572-8587
    Keywords: evolution ; teleology ; chance ; purpose ; anthropomorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Philosophy , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Summary Revaluation of the problem of natural teleology seems an important precondition for elucidating our environmental crisis and for formulating an ‘ecological ethics’, because it calls for a recognition of an intrinsic value in nature and organisms. Therefore, it is necessary to show that the concept of natural teleology is not in contradiction with scientific theories, in particular not with the theory of evolution. In this paper I shall argue that there is a fundamental misunderstanding about the concepts of teleology and chance in modern thinking. This as a result of a radical transformation of the Aristotelian concept of teleology by Christian theologians during the Middle Ages. This confusion resulted in the rejection of teleology from evolution and in an exaggeration of the role of chance. However, not a solution for the problem of teleology is given here, but only an attempt to prove that neither the fossil-record, nor the role of chance in evolution can give adequate arguments for the negation of teleology in evolution. That is not to say that, therefore there exists teleology in evolution, but the problem of teleology in nature cannot, be solved by the scientific theory of evolution, but only be elucidated by philosophical analysis. At the end of the paper it is argued that teleology must be rather presupposed in evolution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1570-7458
    Keywords: Cryptomyzus ; aphid ; hybridization ; host plant preference ; reproductive performance ; host-alternation ; speciation ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé C. galeopsidis Kaltenbach contient plusieurs formes qui ont différentes relations avec des plantes hôtes et des cycles distincts. Des croisements ont permis d'élucider la taxonomie de ces formes et d'étudier l'hérédité de préférences d'hôtes, des performances reproductives et de l'alternance d'hôtes. Une des formes apparaît comme une espèce distincte par suite de la valeur adaptative réduite des hybrides. Les autres formes avec alternance ou non des hôtes sont considérées comme conspécifiques et représentant deux stratégies vitales différentes. Les performances reproductives sont probablement polygéniques puisque les hybrides ont des performances intermédiaires. Les préférences d'hôtes des hybrides montrent certains degrés de dominance et semblent déterminées par quelques gènes seulement. L'alternance des hôtes est envisagée comme ayant une hérédité monofactorielle. Les conséquences sur la spéciation sont discutées.
    Notes: Abstract The aphid species Cryptomyzus galeopsidis (Kaltenbach) includes several distinct forms which have different host plant relationships and life cycles. Cross breeding was used to elucidate the taxonomic status of these forms and to investigate the inheritance of host preference, reproductive performance and host-alternation. One of the forms appeared to be a distinct species because of the reduced fitness of the hybrids. Other host-alternating and non host-alternating forms are considered conspecific and represent two life cycle strategies. Reproductive performance is probably controlled polygenically, since hybrids show an intermediate performance. Host preference in hybrids showed some degree of dominance and seemed to be determined by only a few genes. Host-alternation is presumed to be inherited monofactorially. The implications for speciation are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Insectes sociaux 38 (1991), S. 263-272 
    ISSN: 1420-9098
    Keywords: Isoptera ; Kalotermitidae ; Neotermes papua ; termites ; caste differentiation ; division of labour ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The direct development ofNeotermes papua (Isoptera: Kalotermitidae) comprises four larval and three nymphal instars before the alate. The first five instars can be easily characterized. The second stage nymphs come morphologically close to the pseudergates, characterized by reduced wing buds. These nymphs can moult stationarily, i.e. with little morphological change, or to presoldiers, or proceed to the alate via the third nymphal stage. Pseudergates originate through a late and reversible deviation from the straight development to the alate. Presoldiers may derive from several stages, up to the last nymphal one; their production is subject to an inhibition by extant soldiers. This developmental schema is congruent with those described in other Kalotermitidae and the Termopsidae. By pinpointing the existence of a large pool of pluripotent individuals, in which the penultimate nymphal stage mingles with pseudergates, the present study also reveals a great similarity betweenNeotermes andProrhinotermes, and suggests that this developmental schema might be generally applicable to termites devoid of a permanent worker caste.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 46 (1990), S. 1117-1126 
    ISSN: 1420-9071
    Keywords: Genetic code ; mitochondria ; evolution ; organelles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The universal genetic code is used without changes in chloroplasts and in mitochondria of green plants. Non-plant mitochondria use codes that include changes from the universal code. Chloroplasts use 31 anticodons in translating the code; a number smaller than that used by bacteria, because chloroplasts have eliminated 10 CNN anticodons that are found in bacteria. Green plant mitochondria (mt) obtain some tRNAs from the cytosol, and genes for some other tRNAs have been acquired from chloroplast DNA. The code in non-plant mt differs from the universal code in the following usages found in various organisms: UGA for Trp, AUA for Met, AGR for Ser and stop, AAA for Asn, CUN for Thr, and possibly UAA for Tyr. CGN codons are not used byTorulopsis yeast mt. Non-plant mt, e.g. in vertebrates, may use a minimum of 22 anticodons for complete translation of mRNA sequences. The following possible causes are regarded as contributing to changes in the non-plant mt: directional mutation pressure, genomic economization, changes in charging specificity of tRNAs, loss of release factor RF2, changes in RF1, changes in anticodons, loss of lysidine-forming enzyme system, and disappearance of codons from coding sequences.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 46 (1990), S. 251-254 
    ISSN: 1420-9071
    Keywords: Bronchial tree ; evolution ; fractal ; lung airway ; morphogenesis ; renormalization group theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The mammalian lung exhibits features of a fractal tree: heterogeneity, self-similarity and the absence of a characteristic scale. The finite nature of the lung ultimately limits the range over which self-similarity scaling characteristics are applicable. However, generalization based on the scaling features of fractals, provides unique insight into geometric organization of anatomic structures. Furthermore, the mathematical theory of renormalization groups provides a description of the harmonically-modulated inverse power-law scaling observed for bronchial tree dimensions observed in different species. Compared to several mammalian species (dog, rat, hamster), the human lung shows marked differences in the phase of the harmonic modulation for both length and diameter measurements. These inter-species scaling differences suggest that evolutionary factors modify certain universal features of morphogenesis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    ISSN: 1423-0445
    Keywords: defensive secretion ; hot secretion ; elytral flanges ; evolution ; benzoquinones ; hydrocarbons ; bombardier beetle ; Coleoptera ; Carabidae ; Paussinae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The Australian bombardier beetle,Mystropomus regularis, sprays a mixture of quinones (1,4-benzoquinone, 2-methyl-1,4-benzoquinone, 2-ethyl-1,4-benzoquinone) and hydrocarbons (principallyn-pentadecane). The defensive fluid ist generated explosively in two-chambered glands, and is ejected audibly and hot (maximal recorded temperature = 59°C).Mystropomus is a member of the paussoid lineage of bombardiers. In common with other members of the group, it has a pair of elytral flanges (flanges of Coanda), associated with the gland openings, that serve as launching guides for anteriorly-aimed ejections of spray. It is argued thatMystropomus may be the least derived of flanged paussoids, and the closest living relative of the most primitive of extant bombardiers (Metriini).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 47 (1991), S. 791-803 
    ISSN: 1420-9071
    Keywords: Phytotoxins ; ecology ; phylogeny ; evolution ; biosynthesis ; coronatine ; phaseolotoxin ; rhizobitoxine ; syringomycin ; syringotoxin ; syringostatin ; tabtoxin ; tagetitoxin ; tropolone ; fireblight toxin ; thaxtomin ; 3-methylthiopropionic acid ; carboxylic acids ; Pseudomonas ; Xanthomonas ; Xanthomonas ; Streptomyces ; Erwinia ; Bradyrhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract This review attempts to rationalise what is known about bacterial phytotoxins and associate it with the ecology and possible evolution of the producing organisms. Study of non-toxin producing variants gives insight into the ecological role of the toxin. Elucidation of chemical structures of phytotoxins has shown that many exist as families of analogous compounds. Studies on the variation of chemical structures and how they are distributed across species and genera can lead to development of hypotheses on evolutionary relationships. Knowledge on biosynthetic pathways to tosins allows recognition of specific enzymatic steps involved in developing the characteristic features of the structures. Phytotoxins often have a potent biochemical activity, and in some cases the producing organism has associated mechanisms to prevent action of the toxin upon itself; in such cases toxigenesis is clearly not a chance event. The various aspects of bacterial toxigenesis indicate that bacterial phytotoxins are special secondary metabolic products that play beneficial roles to the producing organisms in their various ecological niches.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Behavior genetics 20 (1990), S. 109-126 
    ISSN: 1573-3297
    Keywords: Y chromosome ; DNA ; mammals ; evolution ; behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract There is a predominant theory for the evolution of the mammalian Y chromosome. This theory hypothesizes that genes for sex determination and male-specific traits, as well as sequences for X-Y meiotic pairing, are conserved on the mammalian Y chromosome across all lineages and that all other Y chromosomal genes or sequences have been or will be lost in each mammalian lineage. There are effects of mouse Y chromosomal genes on behaviors and other traits that are not male specific. Under the predominant theory, these Y chromosomal genes could be the same as the conserved genes for sex determination or malespecific traits, or they could be genes that have been lost from the Y chromosomes of other mammalian lineages and that will eventually be lost from the Y chromosome of the rodent lineage. Recently, the evolution of the primate and rodent Y chromosomes has been studied at the DNA level. These studies are summarized and reviewed in this article. The findings of these studies are not fully consistent with the predominant theory for the evolution of the mammalian Y chromosome. Also, they imply that there are other possibilities for the phylogenetic history of Y chromosomal genes of mice with effects on behavior. These are that Y chromosomal genes with effects on mouse behaviors or other traits could be conserved genes other than those for sex determination or malespecific traits or that they could be novel genes on the Y chromosome of the rodent orMus lineage.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Biochemical genetics 28 (1990), S. 209-222 
    ISSN: 1573-4927
    Keywords: glycophorin A ; glycophorin B ; evolution ; primates ; chimpanzee ; gorilla ; orangutan ; gibbon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Analysis of nucleotide sequences of the human glycophorin A (GPA) and glycophorin B (GPB) genes has indicated that the GPA gene most closely resembles the ancestral gene, whereas the GPB gene likely arose from the GPA gene by homologous recombination. To study the evolution of the glycophorin gene family in the hominoid primates, restricted DNA on Southern blots from man, pygmy chimpanzee, common chimpanzee, gorilla, orangutan, and gibbon was probed with cDNA fragments encoding the human GPA and GPB coding and 3′-untranslated regions. This showed the presence in all of the hominoid primates of at least one GPA-like gene. In addition, at least one GPB-like gene was detected in man, both chimpanzee species, and gorilla, strongly suggesting that the event that produced the GPB gene occurred in the common ancestor of man-chimpanzee-gorilla. An unexpected finding in this study was the conservation ofEcoRI restriction sites relative to those of the other four enzymes used; the significance of this observation is unclear, but raises the question of nonrandomness ofEcoRI restriction sites in noncoding regions. Further analysis of the evolution of this multigene family, including nucleotide sequence analysis, will be useful in clarification of the evolutionary relationships of the hominoid primates, in correlation with the structure and function of the glycophorin molecules, and in assessment of the role of evolution in the autogenicity of glycophorin determinants.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Biochemical genetics 28 (1990), S. 337-346 
    ISSN: 1573-4927
    Keywords: glutamate dehydrogenase ; Drosophila melanogaster ; gene expression ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We have isolated theDrosophila melanogaster locus coding forl-glutamate dehydrogenase (EC 1.4.1.3) by virtue of its similarity to the corresponding human gene. There is only one copy of this gene in the fruit fly genome, located on the right arm of chromosome 3 (95D1-4). The transcript includes at least one large intron and matures to a ∼2.4-kb-long polyadenylated RNA whose expression is under developmental control.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    ISSN: 1573-4927
    Keywords: restriction fragment length polymorphisms ; glycophorin A ; glycophorin B ; MN blood group ; V-A-B-D blood group ; Vc antigen ; chimpanzee ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Twelve restriction fragment length polymorphisms (RFLPs) were detected in common chimpanzee using two restriction enzymes (HindIII andMspI) and four DNA probes to the coding regions of the human glycophorin A (GPA) and glycophorin B (GPB) genes and their 3′-untranslated regions. Seven RFLPs correlated with red cell expression of the Vc determinant of the MN blood group-related V-A-B-D system and five RFLPs correlated with nonexpression of this antigen. Animals heterozygous for theV allele that encodes the Vc determinant had all 12 polymorphic restriction fragments and appeared to show reduced intensity of probe hybridization to these fragments, consistent with the presence of aV and a non-V allele. No RFLPs were detected withEcoRI,SstI, orBamHI, in spite of the relatively large segment of DNA (at least 20 kb) involved in the polymorphisms. The RFLPs were chimpanzee specific and were not found in man, gorilla, orangutan, or gibbon. Multiple RFLPs distinguishing primate species are rare and may be useful markers for molecular evolution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Biochemical genetics 28 (1990), S. 337-346 
    ISSN: 1573-4927
    Keywords: glutamate dehydrogenase ; Drosophila melanogaster ; gene expression ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We have isolated theDrosophila melanogaster locus coding forl-glutamate dehydrogenase (EC 1.4.1.3) by virtue of its similarity to the corresponding human gene. There is only one copy of this gene in the fruit fly genome, located on the right arm of chromosome 3 (95D1-4). The transcript includes at least one large intron and matures to a ∼2.4-kb-long polyadenylated RNA whose expression is under developmental control.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Behavior genetics 20 (1990), S. 563-568 
    ISSN: 1573-3297
    Keywords: personality ; fertility ; family size ; fitness ; extraversion ; neuroticism ; impulsivity ; genetic architecture ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract The relationship between reproductive success (number of biological children) and personality was explored in 1101 postmenopausal females from the Australian twin registry. The quadratic response surface relating fitness to extraversion (E) and neuroticism (N) showed a saddle point at intermediate levels of E and N. Selection was shown to be stabilizing, i.e.,having an intermediate optimum, along the axis low E, low N-high E, high N and more mildly disruptive, having greater fitness in the extremes, along the axis low N, high E-high N, low E. Neither dimension of personality considered by itself showed a significant linear or quadratic relationship to reproductive success. Sections through the fitness surface, however, show selection tends to favor high neuroticism levels in introverts and low neuroticism levels in extroverts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    ISSN: 1573-5028
    Keywords: Agrobacterium tumefaciens ; Ti plasmid ; evolution ; IS elements ; host range
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The TA regions of biotype III octopine/cucumopine (OC) Ti plasmids are closely related to the TL region of the biotype I octopine Ti plasmids pTiAch5 and pTi15955. Sequence analysis shows that the limited and wide host range biotype III OC TA regions are derived from a common ancestor structure which lacked the 6a gene found in the biotype I octopine TL region. The TA region of the wide host range OC Ti plasmids has conserved most of the original TL-like structure. In most wide host range OC isolates the TA-iaaH gene is inactivated by the insertion of an IS866 element. However, the TA region of the wide host range isolate Hm1 carries an intact TA-iaaH gene. This gene encodes a biologically active product, as shown by root induction tests and indole-3-acetic acid measurements. The limited host range OC Ti plasmids pTiAB3 and pTiAg57 have shorter TA regions which are derived from a wide host range TA region. The AB3 type arose by an IS868-mediated, internal TA region deletion which removed the iaa genes and part of the ipt gene and left a copy of IS868 at the position of the deleted fragment. The pTiAB3 iaa/ipt deletion was followed by insertion of a second IS element, IS869, immediately 3′ of the ipt gene. pTiAg57 underwent the same iaa-ipt deletion as pTiAB3, but lacks the IS868 and IS869 elements. Analysis of the various TA region structures provides a detailed insight into the evolution of the biotype III OC strains.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 16 (1991), S. 335-337 
    ISSN: 1573-5028
    Keywords: Triticum ; wheat ; endosperm ; gliadin ; pseudogene ; duplication ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 16 (1991), S. 537-546 
    ISSN: 1573-5028
    Keywords: Antithamnion sp. ; chloroplast ; Cyanidium caldarium Geitler ; evolution ; red algae ; rRNA operon ; rRNA spacer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The nucleotide sequences of the plastid 16S rDNA of the multicellular red alga Antithamnion sp. and the 16S rDNA/23S rDNA intergenic spacers of the plastid DNAs of the unicellular red alga Cyanidium caldarium and of Antithamnion sp. were determined. Sequence comparisons support the idea of a polyphyletic origin of the red algal and the higher-plant chloroplasts. Both spacer regions include the unsplit tRNAIle (GAU) and tRNAAla (UGC) genes and so the plastids of both algae form a homogeneous group with those of chromophytic algae and Cyanophora paradoxa characterized by ‘small-sized’ rDNA spacers in contrast to green algae and higher plants. Nevertheless, remarkable sequence differences within the rRNA and the tRNA genes give the plastids of Cyanidium caldarium a rather isolated position.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    ISSN: 1573-5028
    Keywords: algae ; endosymbiosis ; evolution ; plastidial DNA ; Rubisco operon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The rbcS gene coding for the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) of the brown alga Pylaiella littoralis is located within the plastid genome and is transcribed as a single polycistronic mRNA with the gene for the large subunit of Rubisco, rbcL. The structure of the Rubisco operon from P. littoralis was determined. Molecular phylogenies for rbcS and rbcL with a wide range of prokaryotes and eukaryotes were constructed which are congruent with recent evidence for polyphyletic plastid origins. Both rbcL and rbcS of the β-purple bacterium Alcaligenes eutrophus clearly cluster with the rhodophyte and chromophyte proteins. The data suggest that the Rubisco operons of red algal and chromophytic plastids derive from β-purple eubacterial antecedents, rather than the cyanobacterial lineage of eubacteria from which other of their genes derive. This implies a lateral transfer of Rubisco genes from β-purple eubacterial ancestors to the cyanobacterial ancestor of rhodophyte and chromophyte plastids.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 17 (1991), S. 641-652 
    ISSN: 1573-5028
    Keywords: F-ATPase ; cyanobacteria ; operon ; evolution ; photosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The two operons atp1 and atp2, encoding the subunits of the FOF1 ATP-synthase, have been cloned and sequenced from the cyanobacterium Synechocystis sp. PCC 6803. The organization of the different genes in the operons have been found to resemble that of the cyanobacteria Synechococcus sp. PCC 6301 and Anabaena sp. PCC 7120. The Synechocystis FOF1 ATP-synthase has nine subunits. A tenth open reading frame with unknown function was detected at the 5′ end of atp1, coding for a putative gene product similar to uncI in Escherichia coli. A promoter structure was inferred for the Synechocystis atp operons and compared to other known promoters of cyanobacteria. Even though the operon structure of atp1 and atp2 in Synechocystis resembles the corresponding operons of Synechococcus, the amino acid sequences of individual gene products show marked differences. Genetic distances between cyanobacterial genes and genes for ATP-synthase subunits from other species have been calculated and compiled into evolutionary trees.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 169 (1990), S. 81-96 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Gramineae ; Festuceae ; Dactylis glomerata ; Enzymatic markers ; phenology ; interploid exchanges ; autopolyploidy ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phylogenetic relationships between sympatric, morphologically indistinguishable diploid and tetraploid plants ofDactylis glomerata L. (Gramineae) in Galicia (Spain) were assessed using allozyme markers for 6 distinct systems. The study exploited recent introduction in Galicia and subsequent hybridization of an alien 4xDactylis subspecies possessing distinct allozymes from those of all the native plants. Opportunities for gene exchanges between the ploidies were estimated from in situ observations of flowering, examination of progenies in 2x/4x natural and experimental crosses, and enzyme analyses. Results show a high genetic similarity between the Galician diploids and tetraploids, which possess peculiar alleles in common. Although the ploidy levels usually have distinct flowering periods, interploidal crosses do occasionally occur. Gene flow is likely much more important from the diploid to the tetraploid level. A good genetic intermixing occurs between the Galician and the alien tetraploid entities which have simultaneous flowering. Autopolyploidization of the diploids followed by various rates of hybridization is proposed as one very probable origin of natural tetraploids inDactylis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 178 (1991), S. 225-233 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Gramineae ; Eleusine ; DNA amount ; intra- and interspecific variation ; karyotypes ; hybridisation ; polyploidy ; domestication ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 2C nuclear DNA amounts were determined in 30 collections belonging to 10 species ofEleusine. About a 2.5-fold variation in genome size is evident in the genus. The 2C DNA amount in the diploid species ranged from 2.50 pg inE. verticillata to 3.35 pg inE. intermedia. In contrast, the tetraploid species showed a range from 4.95 pg inE. africana to 6.13 pg inE. floccifolia. At intraspecific level 10 collections ofE. coracana, 6 ofE. indica, 4 ofE. africana, 2 ofE. tristachya, and 2 ofE. kigeziensis did not show any significant variation. However, 2 collections ofE. floccifolia, connected with polyploidy, displayed about 90% variation. Polyploid species showed approximately double the genome size of that of their corresponding diploids. An evolutionary increase in DNA amount is evident inE. coracana during the course of its origin and domestication fromE. africana.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 210 (1998), S. 57-86 
    ISSN: 1615-6110
    Keywords: Alliaceae ; Allium ; Nuclear DNA amount ; adaptation ; evolution ; infrageneric classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The 4C DNA amounts of 86 species fromAllium subgg.Allium, Rhizirideum, Bromatorrhiza, Melanocrommyum, Caloscordum andAmerallium show a 8.35-fold difference ranging from 35.60 pg (A. ledebourianum, 2n = 16) to 297.13 pg (A. validum 2n = 56). At diploid level the difference is 3.57-fold betweenA. ledebourianum (35.60 pg) andA. ursinum (127.14 pg). This shows that a significant loss and/or gain of DNA has occurred during evolution. On average subgg.Rhizirideum andAllium have less DNA amount than subgg.Melanocrommyum andAmerallium. The distribution of nuclear DNA amounts does not show discontinuous pattern and regular groups. The evolution of genome size has been discussed in relation to polyploidy and genomes, heterochromatin, adaptive changes in morphological characteristics, phenology and ecological factors, and infrageneric classification.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    ISSN: 1573-5125
    Keywords: microcrustaceans ; Daphnia ; evolution ; interspecific hybridization ; molecular systematics ; aquatic ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cladoceran crustaceans are an important component of zooplankton in a wide range of freshwater habitats. Although the ecological characteristics of several cladoceran species have been well studied, biogeographical studies have been hampered by problematic taxonomic affiliations. However, recently developed molecular techniques, provide a powerful tool to subject aquatic taxa to comparative analyses. Here we highlight recent molecular approaches in aquatic ecology by presenting a simple method of DNA preparation and PCR amplification of the mitochondrial DNA (16S rDNA) in species from nine different families within the cladocera. On a broad taxonomic scale, sequence analysis of this mtDNA fragment has been used to produce the first molecular based phylogeny of the cladocera. This analysis clustered the cladoceran families in a fashion similar to that suggested by previous systematic classifications. In a more detailed analysis of the family Daphniidae, nuclear randomly amplified polymorphic DNA (RAPD), mitochondrial restriction fragment length polymorphism (RFLP) and morphological analyses were combined to identify species and interspecific hybrids within the Daphnia galeata species complex across 50 lakes in 13 European countries and one lake in Africa. The study revealed interspecific hybridization and backcrossing between some taxa (D. cucullata and D. galeata) to be widespread, and species and hybrids to frequently occur in sympatry. Genetic, as well as morphological information, suggests the occurrence of D. hyalina outside the Holarctic.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 5 (1990), S. 3-36 
    ISSN: 1572-8404
    Keywords: Material models ; semantic view of theories ; natural history ; ecology ; evolution ; museums ; Joseph Grinnell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Accounts of the relation between theories and models in biology concentrate on mathematical models. In this paper I consider the dual role of models as representations of natural systems and as a material basis for theorizing. In order to explicate the dual role, I develop the concept of a remnant model, a material entity made from parts of the natural system(s) under study. I present a case study of an important but neglected naturalist, Joseph Grinnell, to illustrate the extent to which mundane practices in a museum setting constitute theorizing. I speculate that historical and sociological analyses of institutions can play a specific role in the philosophical analysis of model-building strategies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 5 (1990), S. 149-173 
    ISSN: 1572-8404
    Keywords: Darwinian ethics ; ethics ; evolution ; evolutionary ethics ; M. Ruse ; naturalistic fallacy ; sociobiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Michael Ruse has proposed in his recent book Taking Darwin Seriously and elsewhere a new Darwinian ethics distinct from traditional evolutionary ethics, one that avoids the latter's inadequate accounts of the nature of morality and its failed attempts to provide a naturalistic justification of morality. Ruse argues for a sociobiologically based account of moral sentiments, and an evolutionary based casual explanation of their function, rejecting the possibility of ultimate ethical justification. We find that Ruse's proposal distorts, overextends and weakens both Darwinism and naturalism. So we propose an alternative Darwinian metaethics that both remedies the problems in Ruse's proposal and shows how a Darwinian naturalistic account of the moral good in terms of human fitness avoids the naturalistic fallacy and can provide genuine, even if limited, justifications for substantive ethical claims. Thus, we propose to really take Darwin seriously.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 5 (1990), S. 451-457 
    ISSN: 1572-8404
    Keywords: Auschwitz ; biology ; ethics ; evolution ; moral theory ; naturalistic fallacy ; Richards
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Conclusion Richards's theory, then, fails on three counts. By illegitimately importing a premise from outside of the theory of evolution in order to construct a valid argument, Richards has failed to achieve his objective of deriving a moral theory exclusively from biological facts. By sliding from a causal use of “ought” to a moral one, Richards commits the fallacy of ambiguity. And by insisting that action from the motive of altruism is moral while claiming that an ethical theory which justifies Hitler's camps must be judged false, Richards has falsified his own ethical theory.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 6 (1991), S. 255-274 
    ISSN: 1572-8404
    Keywords: Classification ; diagrams ; evolution ; history ; natural history ; natural system ; ornithology ; phylogeny ; representation ; systematics ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract ‘The Natural System’ is the abstract notion of the order in living diversity. The richness and complexity of this notion is revealed by the diversity of representations of the Natural System drawn by ornithologists in the Nineteenth Century. These representations varied in overall form from stars, to circles, to maps, to evolutionary trees and cross-sections through trees. They differed in their depiction of affinity, analogy, continuity, directionality, symmetry, reticulation and branching, evolution, and morphological convergence and divergence. Some representations were two-dimensional, and some were three-dimensional; n-dimensional representations were discussed but never illustrated. The study of diagrammatic representations of the Natural System is made difficult by the frequent failure of authors to discuss them in their texts, and by the consequent problem of distinguishing features which carried meaning from arbitrary features and printing conventions which did not. Many of the systematics controversies of the last thirty years have their roots in the conceptual problems which surrounded the Natural System in the late 1800s, problems which were left unresolved when interest in higher-level systematics declined at the turn of this century.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 6 (1991), S. 303-324 
    ISSN: 1572-8404
    Keywords: Complexity ; entropy ; evolution ; evolutionary trends ; Herbert Spencer ; progress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract The consensus among evolutionists seems to be (and has been for at least a century) that the morphological complexity of organisms increases in evolution, although almost no empirical evidence for such a trend exists. Most studies of complexity have been theoretical, and the few empirical studies have not, with the exception of certain recent ones, been especially rigorous; reviews are presented of both the theoretical and empirical literature. The paucity of evidence raises the question of what sustains the consensus, and a number of suggestions are offered, including the possibility that certain cultural and/or perceptual biases are at work. In addition, a shift in emphasis from theoretical to empirical inquiry is recommended for the study of complexity, and guidelines for future empirical studies are proposed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 6 (1991), S. 433-437 
    ISSN: 1572-8404
    Keywords: Ethics ; evolution ; evolutionary ethics ; M. Ruse ; naturalistic fallacy ; supervenience
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Out of a concern to respect the naturalistic fallacy, Ruse (1986) argues for the possibility of causal, but not justificatory, explanations of morality in terms of evolutionary processes. In a discussion of Ruse's work, Rottschaefer and Martinsen (1990) claim that he erroneously limits the explanatory scope of evolutionary concepts, because he fails to see that one can have objective moral properties without committing either of two forms of the naturalistic fallacy, if one holds that moral properties supervene on non-moral properties. In this short paper I argue that Rottschaefer and Martinsen's solution fails. If one takes moral properties to supervene on non-moral properties, then either one ends up committing one of the two forms of the naturalistic fallacy or else one is left postulating unbelievable brute metaphysical facts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    ISSN: 1572-8404
    Keywords: Ethics ; evolution ; evolutionary ethics ; M. Ruse ; naturalistic fallacy ; supervenience ; supervenience explanations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract In a recent paper in this journal (Rottschaefer and Martinsen 1990) we have proposed a view of Darwinian evolutionary metaethics that we believe improves upon Michael Ruse's (e.g., Ruse 1986) proposals by claiming that there are evolutionary based objective moral values and that a Darwinian naturalistic account of the moral good in terms of human fitness can be given that avoids the naturalistic fallacy in both its definitional and derivational forms while providing genuine, even if limited, justifications for substantive ethical claims. Jonathan Barrett (this issue) has objected to our proposal contending that we cannot hold for the reality of supervenient moral properties without either falling foul of the naturalistic fallacy or suffering the consequences of postulating inexplicable moral properties. In reply, we show that Barrett's explicit arguments that we commit either the definitional or derivational form of the naturalistic fallacy fail and that his naturalistic intuitions that supervenience explanations of moral properties by nonmoral properties force us into what we call the explanatory form of the naturalistic fallacy also fail. Positively, his objections help us to clarify the nature of the naturalistic fallacy within an evolutionary based naturalistic ethics and to point out the proper role of both supervenience explanations and moral explanations in such an ethics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 13 (1998), S. 443-470 
    ISSN: 1572-8404
    Keywords: Buffon ; Darwin ; Gayon ; species ; individuality ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Gayon's recent claim that Buffon developed a concept of species as physical individuals is critically examined and rejected. Also critically examined and rejected is Gayon's more central thesis that as a consequence of his analysis of Buffon's species concept, and also of Darwin's species concept, it is clear that modern evolutionary theory does not require species to be physical individuals. While I agree with Gayon's conclusion that modern evolutionary theory does not require species to be physical individuals, I disagree with his reasons and instead provide logical rather than historical reasons for the same conclusion.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 13 (1998), S. 255-261 
    ISSN: 1572-8404
    Keywords: evolution ; speciation ; levels of selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Biologists often define evolution as a change in allele frequencies. Consideration of the evolution of the pocket mouse will show that it is possible to have evolution without any change in the allele frequencies in a population (through change in the genotype frequencies). The implications of this for genic selectionism are then discussed. Sober and Lewontin (1982) have constructed an example to demonstrate the “blindness” of genic selectionism in certain cases. Sterelny and Kitcher (1988) offer a defense against these arguments which assumes a conventionalist approach to populations. The example considered here will be shown to offer a more plausible and far-reaching argument against the view that alleles can always be seen as the units of selection.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 13 (1998), S. 233-244 
    ISSN: 1572-8404
    Keywords: reference ; meaning ; individual ; class ; definition ; clade ; evolution ; phylogeny ; phylogenetic taxonomy ; systematics ; tree-thinking ; cladistics ; intention ; extension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Although naming biological clades is a major activity in taxonomy, little attention has been paid to what these names actually refer to. In philosophy, definite descriptions have long been considered equivalent to the meaning of names and biological taxonomy is a scientific application of these ideas. One problem with definite descriptions as the meanings of names is that the name will refer to whatever fits the description rather than the intended individual (clade). Recent proposals for explicit phylogenetic definitions of clade names suffer from similar problems and we argue that clade names cannot be defined since they lack intension. Furthermore we stress the importance of “tree-thinking” for phylogenetic reference to work properly.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 13 (1998), S. 187-204 
    ISSN: 1572-8404
    Keywords: evolution ; meme ; gene ; morality ; culture ; psychological predisposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Dennett (1995) argues that memes or cultural replicators are largely autonomous of genes, and that they are fairly efficacious in determining who we are and what we do. I argue that Dennett's arguments are wrong in several aspects, which we can see by analyzing processes at appropriate levels. Specifically, I argue that it is not true that we as persons are created largely by memes, that our memes are not largely independent of our genes, and that we can use the universality of memes to make inferences about genetic predispositions. Finally, by suggesting an innate psychological mechanism for morality, I argue that morality may be largely the effect of genetic predispositions rather than autonomous.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Springer
    Biology and philosophy 13 (1998), S. 359-391 
    ISSN: 1572-8404
    Keywords: adaptation ; algorithm ; atavism ; contingency ; deep homology ; Dennett ; development ; disparity ; epicurean selectionism ; evolution ; exaptation ; Gould ; metaphors ; punctuated equilibrium ; selectionism ; spandrels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract In his recent book on Darwinism, Daniel Dennett has offered up a species of a priori selectionism that he calls algorithmic. He used this view to challenge a number of positions advocated by Stephen J. Gould. I examine his algorithmic conception, review his unqualified enthusiasm for the a priori selectionist position, challenge Dennett's main metaphors (cranes vs. skyhooks and a design space), examine ways in which his position has lead him to misunderstand or misrepresent Gould (spandrels, exaptation, punctuated equilibrium, contingency and disparity), and discuss recent results in developmental biology that suggest that an a priori position does not fill the demands of an evolutionary biology. I conclude by insisting that evolutionary biology is many leveled, complicated, and is carried on an ever shifting and expanding empirical base that when disregarded results in caricature.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    ISSN: 1573-5125
    Keywords: ecomorphology ; evolution ; feeding ; fish stocks ; major histocompatibility complex ; molecular genetics ; species flock
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A unique species flock of large barbs (Barbus spp.) from Lake Tana is presented, from the level of fish stocks to molecules. Evidence is given for the species status of 14 morphotypes of large barbs. They distinctly differ in: (1) head and body morphometrics, (2) food preferences, (3) distribution patterns, (4) maximal body size, (5) spawning area and period, and (6) molecular genetic characters. Most types show early morphological divergence at small size. Major Histocompatibility Complex (MHC) genes, encoding cell membrane proteins involved in defence against pathogens, were found to be diagnostic for the species' genetic identity. A strong selective pressure on particular amino acid positions in the MHC protein sequence most probably arose in response to different pathogen loads from the newly invaded ecological niches after formation of Lake Tana, ca. two million years ago. Arguments for a sympatric origin of this species flock are discussed. An evolutionary scenario suggests a riverine ancestral Barbus intermedius invading Lake Tana after its formation by volcanic blocking of the Blue Nile river and its isolation by waterfalls. Specialisation for particular food types and disruptive selection on many feeding structures are hypothesized as the evolutionary drive in speciation. The causal relationship between the diversity in feeding structures and food types is explained from experiments and models. As an example, the potential food niche of three barb species is predicted from parameter values measured from a large set of feeding structures and tested against the actual gut contents. The co-occurrence of eight piscivorous barb species is unique for cyprinid fish, which lack oral jaw teeth and a stomach. The significance of this aquatic ecosystem as a multidisciplinary evolutionary laboratory and the need for a wise balance between exploitation and conservation is stressed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    Springer
    Mathematical geology 22 (1990), S. 95-106 
    ISSN: 1573-8868
    Keywords: evolution ; extinction ; macroevolution ; probability ; species longevity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract The longevities of species constituting a statistical population have an underlying distribution whose form and parametric values reflect probabilities of origination and extinction through time. In the case that a part of the population is extant, the form of distribution and its parameters cannot be estimated directly from the longevity data without bias. Longevities of extant “censored” species are truncated and thus do not statistically represent the underlying distribution. The remaining “uncensored” species do not represent the true relative abundances of longevities. These biases can be defined from the probability densities for species longevitys and intervalr between successive originations of species. For realistic densities ofs andr, species with an intermediate longevity are preferentially censored. This simple, general result arises because the probability of censoring a species increases with its longevity, whereas the probability of censoring a given longevity varies with its relative abundance.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    Springer
    Autonomous agents and multi-agent systems 1 (1998), S. 59-88 
    ISSN: 1573-7454
    Keywords: agents ; evolution ; information filtering ; world wide web
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Amalthaea is an evolving, multi-agent ecosystem for personalized filtering, discovery, and monitoring of information sites. Amalthaea's primary application domain is the World Wide Web and its main purpose is to assist its users in finding interesting information. Two different categories of agents are introduced in the system: filtering agents that model and monitor the interests of the user and discovery agents that model the information sources.A market-like ecosystem where the agents evolve, compete, and collaborate is presented: agents that are useful to the user or other agents reproduce, while low-performing agents are destroyed. Results from various experiments with different system configurations and varying ratios of user interests versus agents in the system are presented. Finally issues like fine-tuning the initial parameters of the system and establishing and maintaining equilibria in the ecosystem are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    Springer
    Evolutionary ecology 5 (1991), S. 30-39 
    ISSN: 1573-8477
    Keywords: Optimality ; behaviour ; adaptive landscapes ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary One of the main challenges to the adaptationist programme in general and to the use of optimality models in behavioural and evolutionary ecology in particular is that natural selection need not optimise fitness. This challenge is addressed by considering the evolution of optimal patch choice by natural selection. The behavioural model is based on a state variable approach in which a strategy consists of a sequence denoting the patch to be visited as a function of the organism's state and time. The optimal strategy maximises expected terminal reproduction. The fitnesses of alternative strategies are computed by iteration of the associated equations for fitness; this characterises the adaptive behavioural landscape. There may be enormous numbers of strategies that have near optimal fitnesses. A population model is used to connect frequencies of behavioural types from one generation to the next. Theories on adaptive walks on fitness landscapes are considered in the context of behaviour. The main result is that within the context of optimality arguments at selective equilibrium, sub-optimal behaviours can persist. General implications for research in behavioural ecology, including tests of behavioural theories, are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 36 (1998), S. 285-295 
    ISSN: 1573-5028
    Keywords: Chlamydomonas eugametos ; evolution ; genome sequence ; green algae ; group I introns ; mitochondrial DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The complete nucleotide sequence of the Chlamydomonas eugametos (Chlamydomonadales, Chlorophyceae, sensu Mattox and Stewart) mitochondrial genome has been determined (22 897 bp, 34.6% G + C). The genes identified in this circular-mapping genome include those for apocytochrome b, subunit 1 of the cytochrome oxidase complex, subunits 1, 2, 4, 5, and 6 of the NADH dehydrogenase complex, discontinuous large and small subunit ribosomal rRNAs and three tRNAs whose anticodons CAU, CCA and UUG are specific for methionine, tryptophan and glutamine, respectively. The C. eugametos mitochondrial DNA (mtDNA), therefore, shares almost the same reduced set of coding functions and similar unusual features of rRNA gene organization with the linear 15.8 kb mtDNA of Chlamydomonas reinhardtii, the only other completely sequenced chlamydomonadalean mtDNA. However, sequence analysis of the C. eugametos mtDNA has revealed the following distinguishing features relative to those of C. reinhardtii: (1) the absence of a reverse transcriptase-like gene homologue, (2) the presence of an additional gene for tRNAmet that may be a pseudogene, (3) a completely different gene order, (4) transcription of all genes from the same mtDNA strand, (5) a lower G + C content, (6) less pronounced bias in codon usage, and (7) nine group I introns, several of which contain open reading frames coding for potential maturases/endonucleases and two have a nucleotide at the 5′ or 3′ splice site of the deduced precursor RNAs that deviates from highly conserved nucleotides reported in other group I introns. The features of mitochondrial genome organization and gene content shared by C. eugametos and C. reinhardtii contrast with those of other green algal mtDNAs that have been characterized in detail. The deep evolutionary divergence between these two Chlamydomonas taxa within the Chlamydomonadales suggests that their shared features of mitochondrial genome organization evolved prior to the origin of this group.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    Springer
    The protein journal 10 (1991), S. 145-149 
    ISSN: 1573-4943
    Keywords: Primary structure ; β-chain ; hemoglobin ; Columbiformes ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Primary structure of β-chain of pigeon is presented. It was determined by amino acid sequence analysis of intact β-chain and its peptides obtained by the enzymatic and chemical cleavage. Comparison of amino acid sequence of the chain with other available data shows β 14 Ile, β61 Lys, and β113 Ile as residues specific to pigeon. One important replacement at α1β1 contact is β55 Met→Ser.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Springer
    Evolutionary ecology 12 (1998), S. 153-164 
    ISSN: 1573-8477
    Keywords: algae ; anti-predator adaptations ; arms race ; Chlorella vulgaris ; chrysophytes ; continuous culture ; evolution ; flagellates ; multicellularity ; Ochromonas vallescia ; phagocyte ; predator–prey interactions ; selective pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Predation was a powerful selective force promoting increased morphological complexity in a unicellular prey held in constant environmental conditions. The green alga, Chlorella vulgaris, is a well-studied eukaryote, which has retained its normal unicellular form in cultures in our laboratories for thousands of generations. For the experiments reported here, steady-state unicellular C. vulgaris continuous cultures were inoculated with the predator Ochromonas vallescia, a phagotrophic flagellated protist (‘flagellate’). Within less than 100 generations of the prey, a multicellular Chlorella growth form became dominant in the culture (subsequently repeated in other cultures). The prey Chlorella first formed globose clusters of tens to hundreds of cells. After about 10–20 generations in the presence of the phagotroph, eight-celled colonies predominated. These colonies retained the eight-celled form indefinitely in continuous culture and when plated onto agar. These self-replicating, stable colonies were virtually immune to predation by the flagellate, but small enough that each Chlorella cell was exposed directly to the nutrient medium.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Springer
    Evolutionary ecology 12 (1998), S. 245-250 
    ISSN: 1573-8477
    Keywords: environmental sex determination ; evolution ; nest-site philopatry ; reptiles ; sex ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The reason for the frequent occurrence of environmental sex determination (ESD) in reptiles is still not well understood, although much effort has been devoted to solving the issue. Stimulated by the occurrence of nest-site philopatry in some species, this paper examines a diploid model of the influence of nest-site philopatry on the evolution of ESD. Analysis shows that nest-site philopatry can lead to ESD because the fitnesses of sons and daughters are not influenced in the same way by nest-site quality. Daughters inherit the nest site and thus benefit more than sons from a high-quality nest site. Conversely, the fitness of daughters at low-quality nest sites is lower compared to the fitness of sons. Therefore, genes causing ESD can spread by causing the production of more sons at low-quality nest sites and more daughters at high-quality nest sites. Suggestions are made to test empirically whether nest-site philopatry led to the evolution of ESD.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 229-236 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Asteraceae ; Emilia ; Chromosome numbers ; C-banding ; cytogeography ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Analysis of several populations in a large part of the distribution area of the genusEmilia in Brazil has revealed only two species: the diploidE. sonchifolia and the tetraploidE. fosbergii. The more widely reportedE. coccinea was not found. They show a karyotype constancy in morphology and chromosome number (2n = 10 and 2n = 20, respectively), C-banding pattern and number of secondary constrictions. Some indications were found thatE. fosbergii may be an allopolyploid and that its ancestors had different genome sizes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 171 (1990), S. 1-14 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Compositae ; Chemistry ; systematics ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The broad knowledge of the chemistry of theCompositae allows the discussion of its relevance for the systematics and evolution within the family. Furthermore a separation into subfamilies can be supported by the observed differences in the distribution of the main constituents in the tribes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 211 (1998), S. 43-56 
    ISSN: 1615-6110
    Keywords: Ranunculaceae ; Adonis ; Morphology ; growth pattern ; taxonomy ; ecology ; climatic requirements ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adonis sect.Consiligo is split into three subsections based on morphology, growth pattern, pollen and fruit morphology. For all species distribution maps are provided and discussed with regard to their ecology and climatic requirements. These data reveal additional characters that support the classification of the taxa. Most species of the section grow in continental Eurasiatic steppes and mountain steppe habitats. Only the species of subsect.Amurenses grow in Far Eastern temperate forests and prefer a more oceanic climate. The taxonomic position of these strongly divergent species is supported by the distributional and ecological data. The evolution ofAdonis sect.Consiligo occurred under strong climatic control. During evolution the taxa could only slightly widen their ecological amplitude and, thus, ecology remained rather stable except that of the subsect.Amurenses. Ecological and distributional data can be used to validate taxonomy and phylogeny and reveal additional informations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    ISSN: 1615-6110
    Keywords: Alstroemeriaceae ; Alstroemeria aurea ; A. ligtu ; A. magnifica ; C-band polymorphism ; evolution ; flow cytometry ; genome size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Among a total of 43 accessions ofAlstroemeria aurea, A. ligtu andA. magnifica nuclear DNA amounts (2C-values) showed significant intraspecific variation, 1.09, 1.21 and 1.15 fold, respectively, when determined through flow cytometric measurements of fluorescence of propidium iodide (PI) stained nuclei. After staining with another fluorochrome, 4′,6-diamidino-2-phenylindole (DAPI), an intraspecific variation of 1.10, 1.11 and 1.12 fold, respectively, was found. C-band polymorphisms were present among and within the accessions of all three species. In some cases only very small differences in C-banding pattern were observed. In other cases, however, differences were more prominent. Besides C-band polymorphism, there were also instances of chromosome length polymorphism, which concerned the total chromosome complement or single chromosomes. The variation in nuclear DNA amount inA. aurea andA. ligtu was more or less continuous, except for one accession ofA. ligtu subsp.simsii. Artificial selection and possibly introgression of chromosomes from other species may have moulded the karyotypes of some of the accessions ofA. aurea, a species that has been under cultivation for more than 160 years. The variation as observed inA. magnifica subsp.magnifica was discontinuous and could be due to a broad species concept.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 171 (1990), S. 187-197 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Aceraceae ; Acer ; Sympodial and monopodial branching ; evolution ; adaptive strategy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The evolutionary trend and its ecological implications in sympodial and monopodial branching patterns has been investigated in 20 JapaneseAcer spp. through comparison of shoot tip abortion and terminal bud formation. The genus is divided into two species groups according to its branching pattern, one (6 species) predominantly exhibiting sympodial branching with frequent monopodial branching in short shoots (sympodial species), and the other (14 species) exhibiting only monopodial branching (monopodial species). The early ontogeny of leaf and bud scales is described. Despite the difference in branching patterns, the bud scales of terminal buds are essentially the same in having a leaf base developed to function as a protecting organ. In all the sympodial species, during the abortion of a sympodium shoot tip, one or two pairs of primordia were found to occur on the apex, and later wither. These primordia resemble bud scales of terminal buds in their ontogeny and morphology, and appear to be rudimentary. It is suggested that a rudimentary terminal bud develops together with the establishment of sympodial branching, and that sympodial branching has originated from monopodial branching. Based on this proposed evolutionary trend, it is suggested thatAcer has moved from less shady habitats into shady habitats with monopodial branching (advantageous for vertical growth) changing into sympodial branching (advantageous for lateral spread).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 170 (1990), S. 107-124 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Betulaceae ; Alnus ; Isozymes ; population genetics ; hybridization ; genetic distance ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The actinorhizal genusAlnus contains numerous taxa that have been morphologically classified into different subgenera, species and subspecies. The genetic divergence has been evaluated within subg.Alnobetula between the parapatric taxaAlnus sinuata andA. crispa, using diversity of allozyme markers at 15 structural loci among 20 populations. Evidence for introgressive hybridization at the overlap of their ranges was noted in three populations. However, the width of the hybrid zone appeared tenuous. The average genetic distance derived from the comparisons of conspecific populations was much smaller than the interspecific distance (D = 0.047). This allelic divergence was also paralleled with larger amounts of allelic and genotypic diversity within and among populations ofA. sinuata, which are occupying a more heterogenous ecological niche. It is proposed that the repeated advances and retreats of the ice sheet during the Pleistocene may have promoted the divergence and allopatric evolution of these subspecies, and that secondary contact may have occurred repeatedly during the interglacial periods. The dynamic-equilibrium model would predict in such cases that narrow hybrid zones, formed at the contact of parapatric ranges, would impede gene exchange between parental taxa by selection against hybrids. The results obtained in this study seemed concordant with this hypothesis, as they were also in agreement with the existent taxonomical treatment of these taxa based on morphology.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 83-97 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Pooideae ; Phylogenetics ; evolution ; chloroplast DNA ; restriction site variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A phylogenetic analysis was conducted on chloroplast DNA restriction site variation in 34 genera of grasses (familyPoaceae), including 28 genera from subfam.Pooideae (representing tribesAveneae, Brachypodieae, Bromeae, Meliceae, Poeae, Stipeae, andTriticeae) and representatives of three other subfamilies,Arundinoideae, Oryzoideae, andPanicoideae. Analyses of all 34 genera always distinguishedPooideae as monophyletic, regardless of which nonpooid genus functioned as outgroup; six separate analyses of all 28 pooid genera, each including one of the six nonpooid genera as outgroup, resolved five identically-constituted clades withinPooideae (in four cases), or (in the other two cases) yielded results that were less well resolved, but not in conflict with those of the other four analyses. The four best-resolved analyses distinguishedMeliceae as the earliest diverging lineage withinPooideae, andStipeae as the next. Above the point of divergence ofStipeae is a dichotomy between supertribeTriticodae (including tribesBrachypodieae, Bromeae, andTriticeae), and a clade comprisingPoeae andAveneae. The analysis supports some tribal realignments, specifically the assignment ofBriza, Chascolytrum, Microbriza, andTorreyochloa toAveneae, andArctagrostis, Catabrosa, andSesleria toPoeae. The analysis also suggests that the pooid spikelet (i.e., glumes shorter than lemmas and florets two or more) is plesiomorphic inPooideae, and that spikelets with one floret, and those with glumes longer than the first lemma, each have evolved more than once withinPooideae. Results also indicate that small chromosomes and chromosome numbers based on x=c. 10−12 are plesiomorphic withinPooideae. Alternative states of these characters (chromosomes large, chromosome numbers based on x=7) are interpreted as synapomorphies or parallelisms of clades that includeTriticodae, Aveneae, andPoeae. Lanceolate lodicule shape may be a synapomorphy of the clade that includesStipeae, Triticodae, Aveneae, andPoeae, and loss of lodicule vascularization a synapomorphy of the entirePooideae.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 172 (1990), S. 205-213 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Brassicaceae ; Capsella ; Ribulose-1,5-bisphosphate carboxylase/oxygenase ; isoelectric focusing ; evolution ; polyploidization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1.39) and its subunits (large subunits = LSU, small subunits = SSU) were isolated from threeCapsella spp. by gel electrophoresis and polypeptide composition was analyzed by isoelectric focusing (IEF) in the presence of 8M urea. The described techniques are recommended for large scale systematic studies. Multiple IEF banding patterns of the SSU are probably the outcome of a heterogenous multigene family. The two diploid speciesC. rubella andC. grandiflora show an identical IEF pattern and could be differentiated from the putative allotetraploidC. bursa-pastoris only by the SSU banding pattern. Uniqueness of some SSU bands in the tetraploid and in the two diploid species, respectively, may indicate an ancient alloploid origin of tetraploidC. bursa-pastoris followed by events leading to divergences in the genomes of the allotetraploid and its presumed diploid progenitors after the hybridization event (SSU gene elimination, acquisition of new SSU genes).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 174 (1991), S. 47-66 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Hordeum patagonicum complex ; barley ; Classification ; numerical methods ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Seeds of theHordeum patagonicum complex were collected from the field and grown in the greenhouse. The aim was to take a sample of members of the complex, and on the basis of the phenotypic similarities in some morphological and physiological characters, determine whether distinct groups exist. When cluster analyses, to generate hypotheses, and orthodox statistical procedures, for hypotheses obtained a priori, were applied to the reproductive morphology, germination and flowering patterns, onlyH. patagonicum subsp.magellanicum, out of the five recognized taxa, could be distinguished consistently. The remaining four taxa, which overlapped considerably, could be re-formed into three groups whose centroids were different but whose ranges of variation were not distinct from each other. We conclude that the highly cross-compatible members of theH. patagonicum complex, first defined as species and later redefined as subspecies are probably no more than biotypes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 175 (1991), S. 73-86 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Hyacinthaceae ; Ornithogalum subg.Heliocharmos ; O. angustifolium ; O. divergens ; O. monticolum ; O. tenuifolium ; O. umbellatum ; Numerical taxonomy ; systematics ; evolution ; Flora of France
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Macromorphological variation within theOrnithogalum umbellatum L. (Hyacinthaceae) complex in France was studied. The resulting data were treated by numerical taxonomy methods. Three morphs can be identified: one corresponding to diploid plants, another made up of triploids and a third which encompasses plants having ploidy level above 3x (4x, 5x, and 6x). A systematic interpretation of the complex is proposed wherein only one species,O. umbellatum, is retained. This species corresponds to a polyploid complex undergoing evolution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 176 (1991), S. 125-131 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Polygonaceae Aconogonon campanulatum ; Heterostyly ; floral dimorphism ; pollination ; dioecy ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Heterostyly is clearly confirmed inAconogonon campanulatum. This distylous species is dimorphic for tepals, styles, stigma surface, stamens, pollen grain size, and pollen sexine ornamentation. The floral shape is campanulate and thrum flowers are slightly larger than pin flowers. Small solitary bees were observed as flower visitors and probably effected pollination. The possible evolution of dioecy via heterostyly within the genusAconogonon is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 177 (1991), S. 93-110 
    ISSN: 1615-6110
    Keywords: Basidiomycetes ; Corticiaceae ; Speciation ; distribution ; biohistory ; mating system ; evolution ; population structures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Evolutionary processes inCorticiaceae (wood-inhabiting basidiomycetes) are discussed on the basis of sibling species analysis, colonization strategies, and the known present distribution. It is proposed that the phylogenetical differentiation of basidiocarp structures may be very old and many species have remained unchanged. Subsequent evolution has to a great part been the effect of biological interaction with the environment, like colonization of new substrata, and the formation of species complexes may be a consequence of this. The amount of spores liberated from a single basidiocarp is regarded as an adaptive character for dispersal mainly in the immediate environment. The actual, wide distribution of many species is supposed to be associated with expansion of pertaining forest types in the past. When rapid expansion of a species occurs it is likely to be connected with occupation of a new ecological niche. Finally, the consequences for fungal communities in modern forestry are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    ISSN: 1573-5028
    Keywords: Arabidopsis thaliana ; transposable element ; En-1 ; mutagenesis ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The behavior of the autonomous maize transposable element En/Spm of maize was studied in Arabidopsis. Transgenic Arabidopsis plants carrying En-1 elements were propagated for 12 generations using a single seed descent procedure. The distribution and activity of the En-1 element was monitored using Southern DNA hybridisations in generations 1, 6 and 12. In the first generation the highest number of En-1 insertions per line was 7, which increased to 20 in generation 12. The average number of En-1 insertions increased only slightly in the population, due to a gradual accumulation of segregants that lost the transposable element. During the development of the En-1 mutagenised population the element remained active even in the high-copy lines. In situ hybridisation demonstrated that multiple En-1 insertions were distributed over all Arabidopsis chromosomes. From the initial En-1 mutagenised populations many unstable gene mutations were recovered, indicating that En-1 can be used as a efficient tool for gene tagging in Arabidopsis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    ISSN: 1573-5028
    Keywords: evolution ; fluorescence in situ hybridization (FISH) ; genome ; repetitive DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Isolation and characterization of the most prominent repetitive element families in the genome of tetraploid cotton (Gossypium barbadense L; [39]) revealed a small subset of families that showed very different properties in tetraploids than in their diploid progenitors, separated by 1-2 million years. One element, B77, was characterized in detail, and compared to the well-conserved 5S and 45S rRNA genes. The 572 bp B77 repeat was found to be concentrated in several discontinuous tandem arrays confined to a single 550 kb SalI fragment in tetraploid cotton. Genetic mapping based on the absence of the pentameric ‘rung’ in the G. barbadense ‘ladder’ showed that B77 maps to a D-subgenome chromosome. In situ hybridization supports the contention that the array is confined largely to a single chromosomal site in the D-subgenome. The B77 repeat has undergone a substantial increase in copy number since formation of tetraploid cotton from its diploid relatives. RFLPs observed among tetraploid cotton species suggest that amplification and/or rearrangement of the repeat may have continued after divergence of the five tetraploid cotton species. B77 contains many short direct repeats and shares significant DNA sequence homology with a Nicotiana alata retrotransposon Tna1-2 integrase motif. The recent amplification of B77 on linkage group D04 suggests that the D-subgenome of tetraploid cotton may be subject to different evolutionary constraints than the D-genome diploid chromosomes, which exhibit few genome-specific elements. Further, the abundance of B77 in G. gossypioides supports independent evidence that it may be the closest extant relative of the D-genome ancestor of cotton.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 48 (1990), S. 25-43 
    ISSN: 1573-5060
    Keywords: Cultivated plants ; wild plants ; cyanogenesis ; ecology ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Cyanogenesis, the production of HCN is a trait that can be found in all the major taxa. The system is particularly important in higher plants, both in view of the specialized mechanisms found in plants and with regard to the physiological and ecological function of HCN production. The present paper discusses the long history of cyanogenic research, the distribution of the cyanogenic substances among the taxa of higher plants, their localisation in the plant organs and their biosynthetic pathways. The same topics are discussed with regard to the specialized β-glucosidases found in plants that play a role in the catabolism of the cyanogenic substances and in HCN production. The physiological and ecological functions of the cyanogenic systems are discussed with emphasis on the few species studied so far that are polymorphic, i.e. contain cyanogenic and acyanogenic individuals in the same population. Although research in this area is still in its infanthood, it is clear that cyanogenesis is part of a complex system that among others, gives protection against particular groups of herbivores. Apparently the defensive system is under some kind of constraint, developmental, selectional, or both, that prevents plants from having an absolute defense against herbivores. One such constraint viz. a negative effect of the cyanogenic system on growth and/or reproduction is discussed in some length. A number of cultivated species, i.e. cassava (Manihot esculenta), sorghum (Sorghum spp) and lima bean (Phaseolus lunatus) to mention a few, are cyanogenic. Cyanogenesis in species used for human or lifestock consumption is generally considered an undesirable trait. On the other hand low levels of cyanogenesis may cause greater susceptibility to herbivores and consequently lower the yield. Apparently cyanogenesis is a character of interest for plant breeders trying to improve cyanogenic species.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    ISSN: 1573-5079
    Keywords: evolution ; photosynthesis ; protein structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract There are basic structural similarities between plant PS II and bacterial RCs of the Chloroflexaceae and Rhodospirillaceae. These RCs are referred to as PS II-type RCs. A similar relationship of PS I RC to PS II-type RCs has not been established. Although plant PS I and PS II RCs show structural and functional differences, they also share similarities. Therefore, the A and B polypeptides of PS I were searched for PS II D1 and D2 polypeptide-like sequences. An alignment without gaps was found between PS II-type D2/M helix IV and PS I B helix X, as well as a weaker alignment of PS II-type D1/L with PS I B helix X. No comparable alignment with PS I A was found. In the M/D2 alignment there were eight identities and some conservative substitutions in twenty nine residues. PS I B helix X appeared to contain a modified chlorophyll dimer and monomer binding site and a modified non-heme iron-quinone binding site. The conserved residue sequence was found only in RC polypeptides. The proposed chlorophyll dimer-monomer binding site was located transmembrane from the iron-sulfur cluster X binding site. The conserved residues generally are those that interact with prosthetic groups. Half of the conserved residues are located on the same side of the helix. Thus, although there are impediments to concluding firmly that PS I B helix X has a functional and evolutionary relatedness to the D2 PS II and bacterial M RC polypeptides, our analysis gives reasonable support to the idea.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    ISSN: 1573-5117
    Keywords: Acanthocephala ; aschelminthes ; cladistics ; evolution ; Gnathostomulida ; phylogeny ; pseudocoelomates ; Rotifera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We investigated phylogenetic relationships of phylum Rotifera using cladistic analysis to uncover all most-parsimonious trees from a data set comprising 60 morphological characters of nine taxa: one Acanthocephala, six Rotifera, and two outgroups (Turbellaria, Gnathostomulida). Analysis of our matrix yielded a single most-parsimonious tree. From our analysis we conclude the following: (1) Class Digononta is paraphyletic; (2) it is still premature to reject rotiferan monophyly; (3) the classification hierarchy that best conforms to this morphologically based, cladistic analysis is similar to several traditional schemes. In spite of these results, it is significant that this analysis yielded a tree that is incongruent with those trees developed from molecular data or by using the principles of evolutionary taxonomy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 287-388 (1998), S. 109-115 
    ISSN: 1573-5117
    Keywords: behavior ; mating ; evolution ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The recent isolation of a mate recognition pheromone in the marine rotifer Brachionus plicatilis Müller has shed new light on the mate recognition system of rotifers. One result is improved understanding of the importance of mating behavior as a highly efficient process used by rotifers to choose conspecifics. There are many differences in the main characteristics of mating behavior in members of five different families of rotifers. The present work describes the use of these characteristics to assess species boundaries, especially where boundaries between two or more species are unclear. The method proposed here can assess quantitatively the response of males of one species to females of a questionable taxon by measuring the percentage of matings initiated and the number of completed copulations. The data generated can then be used together with molecular, morphological, and other data to determine the species boundaries. This approach can help distinguish between morphological differences resulting from evolutionary divergence of species and morphological differences induced by environmental or ecological factors.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    ISSN: 1573-5117
    Keywords: Hydra ; size ; endosymbiosis ; model ; evolution ; constraints
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Green hydra with endosymbionts are smaller than brown asymbiotic ones. Regeneration experiments, mitotic index studies on algal and hydra tissue, and evidence for consumption and expulsion of algae are reviewed and it is suggested that larger green hydra have more difficulty controlling algal increase than smaller ones and that hydra have an upper size limit for maintenance of stable symbioses. A mathematical model is discussed which starts with simple physiological assumptions about hydra and generates field testable conclusions about how body and bud size, and reproductive rates depend on food particle size, quantity and temporal distribution. Unlike most analytic ecological-evolutionary models, this one integrates physiology, ecology and evolution without needing simplifying assumptions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 227 (1991), S. 315-321 
    ISSN: 1573-5117
    Keywords: protonephridia ; Platyhelminthes ; ultrastructure ; evolution ; phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three types of flame bulbs are distinguished in the Platyhelminthes: type 1 has two cilia arising from a terminal cell and rootlets extending along the weir; type 2 has many cilia arising from a terminal cell and the proximal canal cell closely aligned with it; and type 3 has a non-terminal perikaryon forming many flame bulbs, each with many cilia and a single row of longitudinal ribs. Each type appears in various structural forms. Type 1 is found in the Catenulida; type 2 in the Macrostomida, Polycladida, Prolecithophora, Proseriata, Tricladida, Fecampiidae, and Neodermata; and type 3 in the Rhabdocoela and Lecithoepitheliata. The most likely evolutionary sequence is that type 3 is derived from type 2 and, perhaps, that type 2 is derived from type 1. Characters of the protonephridia show that the Rhabdocoela and the Neodermata form separate phylogenetic lineages; other similarities between these taxa are due to convergent evolution (or horizontal gene transfer?).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 387-388 (1998), S. 109-115 
    ISSN: 1573-5117
    Keywords: behavior ; mating ; evolution ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The recent isolation of a mate recognition pheromone in the marine rotifer Brachionus plicatilis Müller has shed new light on the mate recognition system of rotifers. One result is improved understanding of the importance of mating behavior as a highly efficient process used by rotifers to choose conspecifics. There are many differences in the main characteristics of mating behavior in members of five different families of rotifers. The present work describes the use of these characteristics to assess species boundaries, especially where boundaries between two or more species are unclear. The method proposed here can assess quantitatively the response of males of one species to females of a questionable taxon by measuring the percentage of matings initiated and the number of completed copulations. The data generated can then be used together with molecular, morphological, and other data to determine the species boundaries. This approach can help distinguish between morphological differences resulting from evolutionary divergence of species and morphological differences induced by environmental or ecological factors.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    ISSN: 1573-5117
    Keywords: Acanthocephala ; aschelminthes ; cladistics ; evolution ; Gnathostomulida ; phylogeny ; pseudocoelomates ; Rotifera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We investigated phylogenetic relationships of phylum Rotifera using cladistic analysis to uncover all most-parsimonious trees from a data set comprising 60 morphological characters of nine taxa: one Acanthocephala, six Rotifera, and two outgroups (Turbellaria, Gnathostomulida). Analysis of our matrix yielded a single most-parsimonious tree. From our analysis we conclude the following: (1) Class Digononta is paraphyletic; (2) it is still premature to reject rotiferan monophyly; (3) the classification hierarchy that best conforms to this morphologically based, cladistic analysis is similar to several traditional schemes. In spite of these results, it is significant that this analysis yielded a tree that is incongruent with those trees developed from molecular data or by using the principles of evolutionary taxonomy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    Springer
    Genetica 102-103 (1998), S. 61-69 
    ISSN: 1573-6857
    Keywords: neutral theory ; slightly deleterious ; evolution ; mutations ; mitochondrial DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A simple neutral model predicts that the ratio of non-synonymous to synonymous fixed differences between species will be the same as the ratio of non-synonymous to synonymous polymorphisms within species. This prediction is tested with existing mitochondrial datasets from 25 animal species. In slightly over half of the studies, the ratio of replacement to silent polymorphisms within species is significantly greater than the ratio of replacement to silent fixed differences between species. These observations are best explained by a substantial number of mildly deleterious amino acid mutations that contribute to heterozygosity but rarely become fixed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    Springer
    Genetica 102-103 (1998), S. 229-239 
    ISSN: 1573-6857
    Keywords: evolution ; fertility ; natural selection ; population genetics ; viability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A theoretical analysis was carried out on the mutation load observed in long-maintained inbred lines from two experiments with Drosophila and mice. The rate of decline in fitness and its sampling distribution were predicted for both experiments using Monte Carlo simulation with a range of mutational parameters and models. The predicted rates of change in fitness were compared to the empirical observed rates, which were close to zero. The classical hypothesis of many deleterious mutations (about one event per genome per generation) of small effect (1–2%) resulting in a mutation pressure for fitness of about 1% per generation is incompatible with the data. Recent estimates suggesting an overall mutation pressure for fitness traits of about 0.1% are, however, compatible with the observed load.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    ISSN: 1573-6857
    Keywords: Drosophila ; evolution ; sex chromosomes ; Y chromosome degeneration ; Y chromosome mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Y chromosome degeneration is characterized by structural changes in the chromosome architecture and expansion of genetic inertness along the Y chromosome. It is generally assumed that the heteromorphic sex chromosome pair has developed from a pair of homologues. Several models have been suggested. We use the unique situation of the secondary sex chromosome pair, neo-Y and neo-X (X2), in Drosophila miranda to analyze molecular mechanisms involved in the evolutionary processes of Y chromosome degeneration. Due to the fusion of one of the autosomes to the Y chromosome (about 2 Mya), a neo-Y chromosome and a neo-X chromosome, designated X2, were formed. Thus, formerly autosomal genes are inherited now on a pair of sex chromosomes in D. miranda. Analyzing DNA sequences from the X2 and neo-Y region, we observed a massive accumulation of DNA insertions on the neo-Y chromosome. From the analysis of several insertion elements, we present compelling evidence that the first step in Y chromosome degeneration is driven by the accumulation of transposable elements, especially retrotransposons. An enrichment of these elements along an evolving Y chromosome could account for the switch from a euchromatic into a heterochromatic chromatin structure.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Electronic Resource
    Electronic Resource
    Springer
    Journal of bioenergetics and biomembranes 22 (1990), S. 593-618 
    ISSN: 1573-6881
    Keywords: Chemotherapy ; ATP ; drug transport ; colchicine ; actinomycin D ; doxorubicin ; vinblastine ; vincristine ; introns ; evolution ; P-glycoprotein ; transmembrane domains ; MDR1 gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Multidrug resistance in animal cells is defined as the simultaneous resistance to a variety of compounds which appear to be structurally and mechanistically unrelated. One type of multidrug resistance is characterized by the decreased accumulation of hydrophobic natural product drugs, a phenotype which is mediated by an ATP-dependent integral membrane multidrug transporter termed P-glycoprotein or P170. The gene coding for P170 is calledMDR. The nucleotide-binding domain of P-glycoprotein shares sequence homology with a family of bacterial permease ATP-binding components. In addition, P170 as a whole is structurally very similar to a number of prokaryotic and eukaryotic proteins believed to be involved in transport activities. This review summarizes our current knowledge of the molecular biology and clinical significance ofMDR expression and P-glycoprotein transport activity, as well as some theories about the function of this protein in normal cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Electronic Resource
    Electronic Resource
    Springer
    Journal of bioenergetics and biomembranes 30 (1998), S. 15-24 
    ISSN: 1573-6881
    Keywords: Cytochrome oxidase ; nitric oxide reductase ; respiration ; denitrification ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Nitric oxide reductase (NOR) is a key enzyme in denitrification, reforming the N–N bond (making N2O from two NO molecules) in the nitrogen cycle. It is a cytochrome bc complex which has apparently only two subunits, NorB and NorC. It contains two low-spin cytochromes (c and b), and a high-spin cytochrome b which forms a binuclear center with a non-heme iron. NorC contains the c-type heme and NorB can be predicted to bind the other metal centers. NorB is homologous to the major subunit of the heme/copper cytochrome oxidases, and NOR thus belongs to the superfamily, although it has an Fe/Fe active site rather than an Fe/Cu binuclear center and a different catalytic activity. Current evidence suggests that NOR is not a proton pump, and that the protons consumed in NO reduction are not taken from the cytoplasmic side of the membrane. Therefore, the comparison between structural and functional properties of NOR and cytochrome c- and quinol-oxidizing enzymes which function as proton pumps may help us to understand the mechanism of the latter. This review is a brief summary of the current knowledge on molecular biology, structure, and bioenergetics of NOR as a member of the oxidase superfamily.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    ISSN: 1573-7055
    Keywords: Artiodactyla ; hippopotamuses ; Cetacea ; morphology ; cytochrome b ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A character analysis of selected conservative morphological traits from extant and fossil artiodactyls and cetaceans was combined with a similar analysis of conservative nucleotide positions from the complete mitochondrial cytochrome b sequences of available extant artiodactyls, cetaceans, sirenians, perissodactyls, and other mammals. This combined analysis focuses on the evidence that supports conflicting hypotheses of artiodactyl monophyly, including the affinities of hippopotamids and the monophyly or paraphyly of odontocete cetaceans. Highly conserved morphological traits of the astragalus and deciduous dentition provide strong corroboration of artiodactyl monophyly, including extant and fossil hippopotamids. In contrast, cytochrome b gene sequences are incapable of confirming this monophyly, due to excessive homoplasy of nucleotide and amino acid traits within extant Eutheria. In like manner, highly conserved and uniquely derived morphological features of the skull and auditory regions provide robust corroboration of Odontoceti monophyly, including extant and fossil physeteroids. Several nucleotide similarities do exist between physeteroids and mysticetes; however, most are either silent third-position transversions or occur also in two or more odontocete families. We suggest that increased taxon sampling, combined with functional considerations of amino acids and their secondary structure in protein-coding genes, are essential requirements for the phylogenetic interpretations of molecules at higher taxonomic levels, especially when they conflict with well-supported hypotheses of mammalian phylogeny, corroborated by uniquely derived morphological traits from extant and fossil taxa.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Electronic Resource
    Electronic Resource
    Springer
    Journal of mammalian evolution 5 (1998), S. 65-93 
    ISSN: 1573-7055
    Keywords: Multituberculata ; inner ear ; cochlea ; semicircular canals ; hearing ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The inner ear of the Late Cretaceous multituberculates Nemegtbaatar gobiensis and Chulsan-baatar vulgaris is described from serial sections and enlarged models. The size and proportions of the inner ear as a whole are as expected for extant small mammals. The lengths of the cochlea (Nemegtbaatar gobiensis, 3.0 mm, Chulsanbaatar vulgaris, 2.0 mm) are comparable to those of other multituberculates, when ratios of length of the cochlea to skull length are calculated. The vestibule is not as expanded in the two taxa as in Lambdopsalis, ?Meniscoessus, and ?Catopsalis; the estimated volume for Nemegtbaatar gobiensis is 9 mm3. A slightly laterally curved, anteriomedially directed cochlea, relatively robust ear ossicles, and the estimations of the area of the tympanic membrane and stapedial footplate in Chulsanbaatar suggest high-frequency hearing but a relatively low sensitivity to low-decibel sounds. The semicircular canals of Nemegtbaatar and Chulsanbaatar are fully developed; the size of the anterior, posterior, and lateral canals and their angles and proportions are comparable to those of extant mammals of similar size. The anterior semicircular canal of Nemegtbaatar forms a smooth half-circle and thus is more derived than the angular canal of Ornithorhynchus. The notable differences between the ratio of the width of the lateral semicircular canal to skull length and the size of the vestibule in Nemegtbaatar and the Paleocene multituberculate Lambdopsalis bulla are probably related to different modes of life.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    Springer
    Journal of clinical monitoring and computing 14 (1998), S. 421-424 
    ISSN: 1573-2614
    Keywords: Automated record keeper ; evolution ; management of risk ; object-oriented
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Medicine
    Notes: Abstract In the course of five years the development of an automated anesthesia record keeper has evolved through nearly a dozen stages, each marked by new features and sophistication. Commodity PC hardware and software minimized development costs. Object oriented analysis, programming and design supported the process of change. In addition, we developed an evolutionary strategy that optimized motivation, risk management, and maximized return on investment. Besides providing record keeping services, the system supports educational and research activities and through a flexible plotting paradigm, supports each anesthesiologist's focus on physiological data during and after anesthesia.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    ISSN: 1572-9699
    Keywords: cell size ; competition ; evolution ; fitness ; nutrient specificity ; selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An important problem in microbial ecology is to identify those phenotypic attributes that are responsible for competitive fitness in a particular environment. Thousands of papers have been published on the physiology, biochemistry, and molecular genetics of Escherichia coli and other bacterial models. Nonetheless, little is known about what makes one genotype a better competitor than another even in such well studied systems. Here, we review experiments to identify the phenotypic bases of improved competitive fitness in twelve E. coli populations that evolved for thousands of generations in a defined environment, in which glucose was the limiting substrate. After 10000 generations, the average fitness of the derived genotypes had increased by ∼ 50% relative to the ancestor, based on competition experiments using marked strains in the same environment. The growth kinetics of the ancestral and derived genotypes showed that the latter have a shorter lag phase upon transfer into fresh medium and a higher maximum growth rate. Competition experiments were also performed in environments where other substrates were substituted for glucose. The derived genotypes are generally more fit in competition for those substrates that use the same mechanism of transport as glucose, which suggests that enhanced transport was an important target of natural selection in the evolutionary environment. All of the derived genotypes produce much larger cells than does the ancestor, even when both types are forced to grow at the same rate. Some, but not all, of the derived genotypes also have greatly elevated mutation rates. Efforts are now underway to identify the genetic changes that underlie those phenotypic changes, especially substrate specificity and elevated mutation rate, for which there are good candidate loci. Identification and subsequent manipulation of these genes may provide new insights into the reproducibility of adaptive evolution, the importance of co-adapted gene complexes, and the extent to which distinct phenotypes (e.g., substrate specificity and cell size) are affected by the same mutations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    Springer
    Genetic resources and crop evolution 45 (1998), S. 383-388 
    ISSN: 1573-5109
    Keywords: arcelin ; common bean ; evolution ; lectin-related genes ; lectin-related proteins ; Phaseolus genus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Arcelins are lectin-related proteins detected only in wild beans collected in Mexico and their presence has been related to resistance against the bean weevils. Six arcelin variants have been described and the gene sequence of four of them was determined. We have isolated and sequenced a cDNA clone encoding arcelin 6. Sequence data indicated that this protein is closely related to arcelin 1 and arcelin 2. The cluster dendrogram produced with the multiple alignment of the cDNA clones coding for arcelins showed that arcelins can be divided into three subgroups: i) arcelin 1, arcelin 2 and arcelin 6, ii) arcelin 4 and iii) arcelin 5a and arcelin 5b. Biochemical data indicate that arcelin 3 belongs to the same subgroup of arcelin 4. Southern blot analysis of genomic DNA yielded similar restriction patterns among members of each subgroup, confirming the results obtained with the multiple alignment. Furthermore, the hybridisation patterns were specific for each arcelin variant. On the basis of these evidences, we suggest that the lectin locus could be a useful tool for understanding evolutionary relationships in common bean and in the genus Phaseolus.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Electronic Resource
    Electronic Resource
    Springer
    Genetic resources and crop evolution 45 (1998), S. 119-126 
    ISSN: 1573-5109
    Keywords: Arachis hypogaea ; DNA markers ; molecular polymorphism ; variation ; origin ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Recent studies on the genus Arachis using molecular markers have revealed very little demonstrable polymorphism in the cultivated groundnut, A. hypogaea. This has led to the hasty generalization that the groundnut lacks genetic variation. However, this is in complete contradiction to the results of other lines of investigations into the origin and evolution of A. hypogaea. Further, a characterization of the world collection for various traits also shows significant levels of variation for almost all genetic traits. The literature review in this article suggests that the lack of genetic variation was inferred because of an inadequacy in the material studied, and the range of techniques used to study molecular polymorphism. A comprehensive and rigorous examination of the material available in the groundnut world collection, either by improving current techniques, or by using such advanced techniques as SSRs and AFLP could well reveal polymorphism at the molecular level.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    Springer
    Genetic resources and crop evolution 45 (1998), S. 263-269 
    ISSN: 1573-5109
    Keywords: evolution ; interspecific hybridization ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A new species of oat, Avena insularis, is described. It was collected in southern Sicily where four populations were found on uncultivated clay soil. Morphologically, it is similar to the hexaploid wild oat A. sterilis, but can be distinguished by its smaller and more condensed panicle, less V-shaped dispersal unit and oblong disarticulation scar. Hybrids between A. insularis and the hexaploid cultivated oat A. sativa were obtained only when the latter was the seed parent in crosses. Chromosome pairing of the hybrids at meiosis was irregular with univalents and multivalents, but the mean number of chiasmata per cell was close to that of A. insularis. Furthermore, the hybrids were partially self-fertile. Thus, the newly discovered species seems closer to the hexaploid oats than any other tetraploid species, and is probably the tetraploid progenitor of hexaploid oats. Hybrids between A. insularis and A. magna were sterile because of irregular chromosome pairing at meiosis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 216-217 (1991), S. 539-545 
    ISSN: 1573-5117
    Keywords: Zoantharia ; aggression ; evolution ; acrorhagi ; allogeneic recognition ; catch tentacles ; sweeper tentacles ; competition ; nematocysts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three types of organ (acrorhagi and catch tentacles in sea anemones, and sweeper tentacles in corals) are described with regard to both morphology and ‘aggressive’ function. Species known to possess such organs are listed. Research on the functions of these particular organs is reviewed and some exceptions to their usual behaviour patterns are highlighted. Further research on allogeneic recognition might shed more light on the phylogeny of anemones and corals.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 216-217 (1991), S. 505-508 
    ISSN: 1573-5117
    Keywords: Hydrozoa ; Scyphozoa ; Anthozoa ; 5S ribosomal RNA ; phylogeny ; evolution ; body plan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using nucleotide sequences of 5S ribosomal RNAs from 2 hydrozoan jellyfishes, 3 scyphozoan jellyfishes and 2 sea anemones, a phylogenetic tree of Cnidaria has been constructed to elucidate the evolutionary relationships of radial and bilateral symmetries. The 3 classes of Cnidaria examined herein belong to one branch, which does not include other metazoan phyla such as the Platyhelminthes. The Hydrozoa (having radial symmetry without septa) and the Scyphozoa (having radial symmetry with septa) are more closely related to each other than to the Anthozoa (having bilateral symmetry with septa). In classical taxonomy, multicellular animals are considered to have evolved through organisms with radial symmetry (e.g., Cnidaria) to bilateral symmetry. Our results, however, indicate that the emergence of the Bilateria was earlier than that of the Radiata, suggesting (in opposition to Haeckel's view) that the radial symmetry of Cnidaria is an evolutionary dead end.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    ISSN: 1573-5117
    Keywords: phylogeny ; acanthocephala ; rotifera ; bilateria ; evolution ; 18S rRNA gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Advances in morphological and molecular studies of metazoan evolution have led to a better understanding of the relationships among Rotifera (Monogononta, Bdelloidea, Seisonidea) and Acanthocephala, and their relationships to other bilateral animals. The most accepted morphological analysis places Acanthocephala as a sister group to Rotifera, although other studies have placed Acanthocephala as a sister taxon to Bdellodea or Seisonidea. Molecular analyses using nuclear 18S rRNA and mitochondrial 16S rRNA genes support Acanthocephala as a sister taxon to Bdelloidea, although no molecular data is available for Seisonidea. Combining molecular and morphological analyses of Bilateria leads to a tree with Platyhelminthes, Rotifera, Acanthocephala and Gnathostomulida (and probably Gastrotricha) as a sister group to the annelid-mollusc lineage of the Spiralia (Lophotrochozoa).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    ISSN: 1573-5028
    Keywords: glucosinolates ; cyanogenic glucosides ; biosynthesis ; cytochrome P450 ; evolution ; Capparales
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cDNA encoding CYP79B1 has been isolated from Sinapis alba. CYP79B1 from S. alba shows 54% sequence identity and 73% similarity to sorghum CYP79A1 and 95% sequence identity to the Arabidopsis T42902, assigned CYP79B2. The high identity and similarity to sorghum CYP79A1, which catalyses the conversion of tyrosine to p-hydroxyphenylacetaldoxime in the biosynthesis of the cyanogenic glucoside dhurrin, suggests that CYP79B1 similarly catalyses the conversion of amino acid(s) to aldoxime(s) in the biosynthesis of glucosinolates. Within the highly conserved ‘PERF’ and the heme-binding region of A-type cytochromes, the CYP79 family has unique substitutions that define the family-specific consensus sequences of FXP(E/D)RH and SFSTG(K/R)RGC(A/I)A, respectively. Sequence analysis of PCR products generated with CYP79B subfamily-specific primers identified CYP79B homologues in Tropaeolum majus, Carica papaya, Arabidopsis, Brassica napus and S. alba. The five glucosinolate-producing plants identified a CYP79B amino acid consensus sequence KPERHLNECSEVTLTENDLRFISFSTGKRGC. The unique substitutions in the ‘PERF’ and the heme-binding domain and the high sequence identity and similarity of CYP79B1, CYP79B2 and CYP79A1, together with the isolation of CYP79B homologues in the distantly related Tropaeolaceae, Caricaceae and Brassicaceae within the Capparales order, show that the initial part of the biosynthetic pathway of glucosinolates and cyanogenic glucosides is catalysed by evolutionarily conserved cytochromes P450. This confirms that the appearance of glucosinolates in Capparales is based on a cyanogen ‘predisposition’. Identification of CYP79 homologues in glucosinolate-producing plants provides an important tool for tissue-specific regulation of the level of glucosinolates to improve nutritional value and pest resistance.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    ISSN: 1573-5028
    Keywords: evolution ; G1-S control ; plant cell cycle ; retinoblastoma protein family ; ZmRb
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recent discoveries of plant retinoblastoma (Rb) protein homologues and D-type cyclins suggest that control of the onset of cell division in plants may have stronger parallels with mammalian G1/S controls than with yeasts. In mammals, the Rb protein interacts specifically with D-type cyclins and regulates cell proliferation by binding and inhibiting E2F transcription factors. However, the developmental role of Rb in plants and its potential interaction with cell cycle regulators is unknown. We show that the maize Rb homologue ZmRb-1 is temporally and spatially regulated during maize leaf development. ZmRb-1 is highly expressed in differentiating cells, but almost undetectable in proliferating cells. In vitro, both ZmRb-1 and human Rb bind all classes of plant D-type cyclins with the involvement of a conserved N-terminal Leu-x-Cys-x-Glu (LxCxE) Rb-interaction motif. This binding is strongly reduced by mutation of the conserved Cys-470 of ZmRb-1. ZmRb-1 binds human and Drosophila E2F, and inhibits transcriptional activation of human E2F. We also show that ZmRb-1 is a good in vitro substrate for all human G1/S protein kinases. The functional conservation of proteins that control the G1/S transition in mammals and plants points to the existence of plant E2F homologues. We conclude that evolution of Rb and cyclin D proteins occurred after separation of the fungi from the higher eukaryotic lineage, but preceded the divergence of plant and animal kingdoms.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    ISSN: 1573-5117
    Keywords: Branchiopoda ; Anomopoda ; Radopoda ; trunk limbs ; taxonomy ; morphology ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An investigation, using optical microscopy and SEM, of the trunk limbs of the Anomopoda has revealed a large number of characters, previously underused or unused in taxonomy and comparative morphology. All these characters, which are nicely paralleled by some more conventional traits (head shield and pores, postabdomen, antennae ...), show one clear tendency across all groups studied: a state of complexity at one extreme, and a state of often incisive simplification at the other extreme, with a number of transitional stages in between. The complex character state, which itself is a simplification of the leg structure of the Ctenopoda and other, ‘large’ Branchiopoda, is here considered to represent a primitive condition. The simplified state is considered advanced. Based on this assumption, we list a number of unifying characters (mainly structural aspects of P1 and P2, but also the gnathobase of P3 and P4) for all macrothricid and chydorid-like anomopods, which we unite in the new suborder Radopoda. Non-radopod Anomopoda are not reclassified. We then derive a cascade of (mainly trunk-limb based) characters to work out a hypothesis on the evolution of the Radopoda. The ‘chydorid’ line (basically the former family Chydoridae) is classified as a superfamily (the Eurycercoidea), with three families; the ‘macrothricid’ line is capped by the superfamily Macrothricoidea, with four families. Of these seven families, four are upgraded from subfamily status, the Chydoridae are left status quo, the Macrothricidae are redefined, and the Neothricidae are a new family. The Macrothricidae are further subdivided in two subfamilies, of which the Macrothricinae appear reasonably homogeneous (monophyletic), while the non-Macrothricinae require further study. Some of these (e.g. Guernella) have almost completely lost their P5, a situation parallel to that of the P6 in the Eurycercidae, Acantholeberidae, and Ophryoxidae.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    ISSN: 1573-5117
    Keywords: phylogeny ; acanthocephala ; rotifera ; bilateria ; evolution ; 18S rRNA gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Advances in morphological and molecular studies of metazoan evolution have led to a better understanding of the relationships among Rotifera (Monogononta, Bdelloidea, Seisonidea) and Acanthocephala, and their relationships to other bilateral animals. The most accepted morphological analysis places Acanthocephala as a sister group to Rotifera, although other studies have placed Acanthocephala as a sister taxon to Bdellodea or Seisonidea. Molecular analyses using nuclear 18S rRNA and mitochondrial 16S rRNA genes support Acanthocephala as a sister taxon to Bdelloidea, although no molecular data is available for Seisonidea. Combining molecular and morphological analyses of Bilateria leads to a tree with Platyhelminthes, Rotifera, Acanthocephala and Gnathostomulida (and probably Gastrotricha) as a sister group to the annelid-mollusc lineage of the Spiralia (Lophotrochozoa).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 390 (1998), S. 171-217 
    ISSN: 1573-5117
    Keywords: taxonomy ; palaeoecology ; evolution ; punctuated equilibrium ; prey-predator coevolution ; bottlenecking ; thalassoidism ; zoogeography ; rift lakes ; lacustrine endemism ; Bellamya ; Neothauma ; Kaya
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During late Cenozoic pre-rift times the viviparid genus Bellamya was probably confined to eastern Africa while in the Congo Basin occurred the genera Neothauma and Kaya (a new genus described herein). During the Pliocene, Kaya became extinct and Neothauma became a relict in Lake Tanganyika. All African rift lakes formed during or after the Pliocene were colonised by populations of Bellamya, which evolved into lacustrine endemics. The changes in shell morphology in Bellamya, such as ornamentation functioning as protection against predators, are modest and repetitive in time and space. After the initial adaptations stasis followed, and there is no indication of an arms race between prey and predator in this genus. In the lakes of the western rift that were formed prior to the Pliocene, namely Lake Tanganyika and Palaeolake Obweruka, Neothauma instead of Bellamya was the coloniser. Initially morphological inertia also occurred in this genus both in Tanganyika and, during the first four million years of its existence, in Palaeolake Obweruka, although from the outset this lake contained abundant highly specialised molluscivorous fishes. About 4.5 Ma a major extinction event occurred in the Obweruka Basin which led to the extermination of 50% of the molluscan species but none of the molluscivores. Among the viviparids, only one of the Neothauma species survived, its populations isolated and highly reduced in numbers. Immediately after this crisis a conchological quantum change occurred, the surviving lineage changing into a strongly ornamented thalassoid form. The dramatic morphological change is deemed to have been due to focussed selection by the predators on isolated and small prey populations. A radiative event immediately followed, producing still more strongly ornamented forms. The morphological changes that occurred in the Obwerukan Neothauma, in comparison to the modest and repeated patterns of evolution that can be observed in viviparids from other lakes, provides an example of true or quantum evolutionary change and yields evidence as to how it may have occurred. The fossil record of the fresh water molluscs of the Albertine Basin, thanks to its duration (ca. 12 million years), its relatively fine resolution (0.5–1.0 million years) and its sound chronostratigraphic framework, is a unique resource for understanding the tempo and mode of macroevolution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Electronic Resource
    Electronic Resource
    Springer
    Journal of optimization theory and applications 71 (1991), S. 589-597 
    ISSN: 1573-2878
    Keywords: Mathematical programming ; Monte Carlo optimization ; stochastic adaptation ; Gaussian adaptation ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract Gaussian Adaptation (GA) is a stochastic process that adapts a Gaussian distribution to a region or set of feasible points in parameter space. As a result of the adaptation, GA becomes a maximum dispersion process extending the sampling over the largest possible volume in parameter space while keeping the probability of finding feasible points at a suitable level. For such a process, a general measure of efficiency is defined and an efficiency theorem is proved.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    Springer
    Human evolution 6 (1991), S. 97-115 
    ISSN: 1824-310X
    Keywords: morphometrics ; niche metrics ; locomotor activities ; locomotor environments ; diet ; functional anatomy ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In recent years, comparative observations of primate anatomies have been extended using measurements and computer analyses: morphometrics. A question then follows. Can we extend field observations of animal lifestyles using measurement and computer analysis, using, in other words, a new «niche metrics», for comparison with the morphometrics of animal anatomies? This has been attempted (Oxnard, Crompton & Lieberman, 1990) by «measuring» 17 lifestyle variables (on locomotion, environment and diet) for 28 prosimian primate species. These data have been analysed by multivariate statistical methods entirely similar to those used in morphometrics. The results define groups of prosimian species that seem not to be related directly with taxonomy and evolution, but with functional adaptation to lifestyle. Comparisons between the morphometric and niche metric results reveal a degree of similarity of species grouping in each that is apparently related to adaptation and remarkably detailed. But further study of both the morphometric and niche metric results suggests that questions pertaining to evolution may also be asked. Thus, both morphometric investigations seeking clusterings of anatomical variables and niche metric studies seeking clustering of higher taxonomic groups of species produce results that seem to be of developmental and phylogenetic rather than directly adaptive import. Through the combination of these two approaches, it may eventually be possible to partition both evolutionary and adaptive components, even though, of course, there must always be overlap between them.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Electronic Resource
    Electronic Resource
    Springer
    Human evolution 13 (1998), S. 57-64 
    ISSN: 1824-310X
    Keywords: microsatellite ; evolution ; population genetics ; polypurine blocks ; mutation ; HLA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to understand evolutionary aspects of the highly polymorphicHLA-F microsatellite (heterozygosity〉90%), several alleles of primates were characterized. 576 meioses from 35 CEPH families were investigated for regular transmission. Furthermore 364 healthy, non-related individuals belonging to four populations from distant ethnic groups were analysed to determine the applicability of this locus in population studies. Sequencing revealed alternate (GAGGAA)n blocks spaced by (GAA)n repeats in all primates analysed. The mutation rate of this locus amounts to 1.5%. The mutational patterns follow approximately the one step mutation model. Differential analysis suggests that mutation rates depend on the repeat length. Paternal mutation rates exceed maternal ones. The presence of both allele classes in all human populations investigated indicates that this polymorphism predated raciation. Evidence is provided that the short alleles originated from the longer ones by deletion. Finally the differential analysis of each allele class corroborates the biological history of the studied populations as traced by other genetic markers.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Electronic Resource
    Electronic Resource
    Springer
    Human evolution 5 (1990), S. 99-106 
    ISSN: 1824-310X
    Keywords: evolution ; sociobiology ; ethics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this paper I argue that Darwinian evolutionary theory gives us the key to an adeguate understanding of morality. Althougt in the past the naturalistic fallacy has been thought to be a bar to the application of evolution to ethics I suggest that properly viewed evolutionary ethics can avoid this problems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Electronic Resource
    Electronic Resource
    Springer
    Human evolution 5 (1990), S. 107-118 
    ISSN: 1824-310X
    Keywords: Ethics ; meta-ethics ; sociobiology ; evolution ; justification ; naturalism ; human nature ; morality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Evolutionary biology is supposed to be relevant to ethics by a number of authors. Some of them believe that it may provide and justify basic moral values. Others argue that evolutionary biology is relevant only in a negative way. They assume that it reveals the illusory nature of any attempt to justify basic moral values. In this paper one example of either approach is criticized. An analysis of examples can hardly offer sufficient grounds for a general conclusion. Nevertheless I believe that evolutionary theory is of little help when we deal with the most basic ethical questions. Three themes which are often though to provide a link between evolutionary biology and (meta)ethics — altruism, sociality and human nature — do not in fact establish that link.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Electronic Resource
    Electronic Resource
    Springer
    Photosynthetica 35 (1998), S. 1-11 
    ISSN: 1573-9058
    Keywords: evolution ; hydrogen ; life ; photosynthesis ; radiant energy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photosynthesis, as a fundamental element in the life process, is integrated in the evolution of living systems on the basis of hydrogen cycles on various hierarchic levels. Conversion of radiant energy enables the oxidation of water, whereby free oxygen accumulates in the atmosphere. Hydrogen is (reversibly) stored in organic materials formed under reductive CO2-fixation and by the incorporation of the other elements, which are necessary for living systems. All endergonic processes in living cells are finally driven by the energy released through the clean recombination of protons and electrons with oxygen to water. Duration of the stored energy and the complexity of the systems thus produced is correlated negatively with the conversion efficiency of the radiation energy. Entropy is a unifying principle in the evolution of living systems, inclusive human societies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Electronic Resource
    Electronic Resource
    Springer
    Behavior genetics 21 (1991), S. 433-444 
    ISSN: 1573-3297
    Keywords: genetics ; evolution ; cultural transmission ; path analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract The evolutionary implications of the path-analysis model most often used in human behavior genetics are examined. With directional selection, a model of pure vertical environmental transmission does not respond in a fully adaptive fashion. Unless the coefficients of transmission are exactly 0.50, the population mean will not equilibrate at the selective optimum over time. If there is both genetic and vertical environmental transmission, then the population mean can equilibrate at the selective optimum. In the presence of genetic transmission, vertical environmental transmission increases population fitness and has a strong effect on the rapid movement of the mean toward the selective optimum. This raises the intriguing paradox of why empirical evidence suggests that vertical environmental transmission is usually small when it possesses such important fitness properties.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    Springer
    Evolutionary ecology 12 (1998), S. 615-626 
    ISSN: 1573-8477
    Keywords: development ; evolution ; optimality ; phenotypic variation ; stochastic environments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We used a probabilistic optimization model to explore the joint evolutionary effects of random phenotypic and environmental variation. Two forms of environmental noise were defined in which the optimal phenotype remained constant but all organisms experienced either the same proportionate or the same absolute fitness gains and losses. There was no evolutionary effect of proportionate fitness fluctuations. In contrast, the optimal genotype varied with absolute fitness fluctuations, despite the environmental effect being phenotype-independent. We refer to such phenotype-independent fluctuation in absolute fitness as the ‘fitness threshold model’, because shared fitness effects determine the zero-fitness points (i.e. the baseline) on an intrinsic fitness function. Thus, environmental effects that are unrelated to a focal trait can cause peak shifts in the genetic optimum for the trait. Changes in the fitness threshold not only changed peak locations, but also altered the slopes defining the peaks, and so should alter the rate of evolution towards optima. This model pertains to evolution in any system, unless there is no phenotypic or environmental variance, or the selection function and distribution of phenotypic error assume similar shapes. Our results have many basic and applied implications for topics such as the maintenance of genetic variation, the canalization of development and the management of natural populations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    Springer
    Evolutionary ecology 4 (1990), S. 1-20 
    ISSN: 1573-8477
    Keywords: Community development ; community richness ; component species ; evolution ; habitat ; helminths ; host capture ; parasites ; phylogeny ; species richness ; time hypothesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We examine patterns of community richness among intestinal parasitic helminth communities in fishes, herptiles, birds and mammals with respect to the comparative number of component species in a host population. We show that terrestrial hosts have, on average, fewer component species than aquatic hosts. We also show that the mean number of component species in aquatic hosts increases from fishes through herptiles to birds before declining slightly in mammals. For terrestrial hosts, the mean number of component species increases from herptiles, through birds, reaching a maximum in mammals. We conclude that: (i) habitat of the host is more important in determining community richness than is host phylogeny; (ii) the phenomenon of ‘host capture’ may be largely responsible for increased species richness in some host groups; (iii) aquatic birds harbour the richest intestinal helminth communities; and (iv) as we interpret them, our data refute the time hypothesis, which would predict that fishes as the oldest lifestyle should have the richest helminth communities.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Automated software engineering 5 (1998), S. 447-464 
    ISSN: 1573-7535
    Keywords: design ; domain-oriented design environments ; evolution ; end-user modification ; knowledge construction ; computer network design
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We live in a world characterized by evolution—that is, by ongoing processes of development, formation, and growth in both natural and human-created systems. Biology tells us that complex, natural systems are not created all at once but must instead evolve over time. We are becoming increasingly aware that evolutionary processes are ubiquitous and critical for technological innovations as well. This is particularly true for complex software systems because these systems do not necessarily exist in a technological context alone but instead are embedded within dynamic human organizations. The Center for LifeLong Learning and Design (L3D) at the University of Colorado has been involved in research on software design and other design domains for more than a decade. We understand software design as an evolutionary process in which system requirements and functionality are determined through an iterative process of collaboration among multiple stakeholders, rather than being completely specified before system development occurs. Our research focuses on the following claims about software systems embedded within dynamic human organizations: (1) they must evolve because they cannot be completely designed prior to use, (2) they must evolve to some extent at the hands of the users, and (3) they must be designed for evolution. Our theoretical work builds upon our existing knowledge of design processes and focuses on a software process model and architecture specifically for systems that must evolve. Our theories are instantiated and assessed through the development and evolution of domain-oriented design environments (DODEs)—software systems that support design activities within particular domains and that are built specifically to evolve.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...