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  • Articles  (56)
  • evolution  (54)
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  • Springer  (56)
  • 1995-1999  (56)
  • 1996  (56)
  • Biology  (56)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 163-165 
    ISSN: 1570-7458
    Keywords: olfaction ; EAG ; sensory physiology ; antennal sensitivity ; interspecies hybrids ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 2
    Electronic Resource
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    Entomologia experimentalis et applicata 80 (1996), S. 7-13 
    ISSN: 1570-7458
    Keywords: host-plant selection ; sensory physiology ; neural coding ; deterrents ; peripheral interactions ; receptor sites ; genetics of insects ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recent advances in our understanding of the relationship between chemosensory and behavioural responses to phytochemicals come from a number of studies on ovipositional and food selection behaviour of flies, butterflies, moths and beetles. Establishing input-output relationships has provided insight into the way in which the activity of chemoreceptors is translated into host-plant selection behaviour. This was achieved for both the qualitative contrast acceptance/rejection and for quantifiable preference hierarchies. By now it is clear that the subtlety of coding the complex phytochemical profiles offered by potential host plants relies on across-fibre patterns or ensemblefiring of taste neurons. Progress along these lines depends on unravelling processing pathways in the central nervous system, still a largely unexplored area in herbivorous insects. Increased interest can be noted for the mechanisms operating during the most peripheral events of chemoreception: the interaction of phytochemical and chemoreceptor, determining the specificity of recognition. Evidence for ‘peripheral integration’ has accumulated. Deterrent receptors have an especially puzzling nature. Although such cells respond to a wide array of structurally diverse secondary plant metabolites, their sensitivity profile differs between closely related species. To what extent membrane-bound receptor molecules are involved and what degree of specificity is conferred by these, is largely unknown. Sensitivity to a certain group or class of compounds is determined by single genes in several cases. This allows for a scenario in which single gene mutations affect stimulus-receptor interactions, which might concurrently affect host-plant selection behaviour.
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  • 3
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    Entomologia experimentalis et applicata 80 (1996), S. 320-324 
    ISSN: 1570-7458
    Keywords: multitrophic interactions ; phylogeny ; evolution ; fitness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 4
    Electronic Resource
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    Springer
    Cellular and molecular life sciences 52 (1996), S. 14-24 
    ISSN: 1420-9071
    Keywords: Lycaenidae ; Formicidae ; symbiosis ; mutualism ; parasitism ; communication ; ecology ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Associations with ants, termed myrmecophily, are widespread in the butterfly family Lycaenidae and range from mere co-existence to more or less specific mutualistic or even parasitic interactions. Secretions of specialized epidermal glands are crucial for mediating the interactions. Transfer of nutrients (carbohydrates, amino acids) from butterfly larvae to ants plays a major role, but manipulative communication with the help of odour signals is also involved. By means of myrmecophily, lycaenid butterflies largely escape ant predation, and certain species gain protection through attendant ants or achieve developmental benefits from ant-attendance. Benefits to the ants range from minimal to substantial food rewards. While most lycaenid species maintain facultative relationships with a variety of ant genera, highly specific and obligatory associations have convergently evolved in a number of butterfly lineages. As a corollary, communication systems are largely unspecific in the former, but may be highly specialized in the latter. The sophisticated communication between obligate myrmecophiles and their host ants is tightly connected with the evolutionary rise of specialized life-cycles and thus is a source of augmenting diversity within the butterflies.
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  • 5
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    Cellular and molecular life sciences 52 (1996), S. 503-510 
    ISSN: 1420-9071
    Keywords: Drosophila ; accessory gland ; reproduction ; sexual behavior ; sperm displacement ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Recent results from biochemical and molecular genetic studies of the accessory gland proteins in maleDrosophila are reviewed. The most prominent feature is the species-specific variability. However, the analysis of the sex peptide inD. melanogaster shows that there is a strong homology in the molecular structure to the closely related sibling species, and that divergence increases with increasing phylogenetic distance. For this reason the sex peptide, after being transferred to the female genital tract during copulation, reduces receptivity and increases oviposition only in virgin females belonging to the same species group and subgroup. Even though studies were hitherto limited to a small number of the secretory components, it is evident that the accessory gland proteins play a key role in reproductive success of the fruit fly by changing female sexual behavior, supporting sperm transfer, storage and displacement. Thus, genes encoding the accessory gland proteins are apparently under strong evolutionary selection.
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  • 6
    Electronic Resource
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    Insectes sociaux 43 (1996), S. 375-389 
    ISSN: 1420-9098
    Keywords: Nasutitermitinae ; Subulitermes ; Coatitermes ; Velocitermes ; evolution ; phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The developmental pathways of the neuter castes were studied in three species of Nasutitermitinae from central Panama. The humivorousSubulitermes denisae andCoatitermes clevelandi display several primitive traits: absence of sex dimorphism, representation of both sexes among workers and soldiers, and occurrence of successive worker instars. The litter-dwellingVelocitermes barrocoloradensis has a more complex caste system: female larvae are larger than males and give rise to the large workers, which constitute the bulk of the work force; male larvae proceed to soldiers through a small worker or a special larval instar. The resulting soldier caste is polymorphic. These results support previously formulated hypotheses regarding a link between humivorous diet and reduced polymorphism on the one hand, and between forest-floor foraging and large continuous size variation among soldiers on the other. Whereas the caste systems ofSubulitermes andCoatitermes probably represent a primitive condition,Velocitermes shares derived traits withNasutitermes and the other fully nasute genera previously studied. I therefore hypothesize that ancestors with these advanced features may have spread from the neotropics and be at the origin of most nasute genera, including humivorous taxa, present in other regions.
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  • 7
    ISSN: 1420-9098
    Keywords: Formicidae ; Leptothoracini ; Tetramoriini ; internal transcribed spacer ; social parasitism ; evolution ; phylogenetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A fragment of the internal transcribed spacer (ITS-1) adjacent to the 5.8S rRNA gene of 20 myrmicine ant species was sequenced. Sequence comparisons were carried out between 11 species of the tribe Leptothoracini, five species of the tribe Tetramoriini, three species of the tribe Solenopsidini and one species of the tribe Myrmicini. Additionally, the formicine antCamponotus ligniperda (tribe Camponotini) was analyzed as an outgroup species. Among all investigated species, the fragment had a variable length of ≈ 230–380 bp with only a few conserved sequence elements. The sequences of this fragment were perfectly identical within four palearctic populations ofLeptothorax acervorum indicating that intraspecific variation is rather low. Within the species of Tetramoriini (includingAnergates atratulus) 94.1% of sequence positions were identical, 95.6% within the species of theLeptothorax s.str.-group and 64.6% within the species of theMyrafant-group. Phylogenetic analysis reveals that the social parasitesHarpagoxenus sublaevis, Doronomyrmex goesswaldi, D. kutteri andD. pacis, Chalepoxenus muellerianus as well asStrongylognathus alpinus andTeleutomyrmex schneideri are most closely related to the groups of their respective host species, which generally confirms the taxonomical classifications of the subfamily Myrmicinae based on morphological criteria. The taxonomical positions of the speciesA. atratulus has as yet been uncertain, however, sequence comparison of the ITS-1 fragment leads to the conclusion thatA. atratulus rather belongs to the tribe Tetramoriini than to the Solenopsidini.
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  • 8
    ISSN: 1423-0445
    Keywords: sex pheromone ; synergist ; antagonist ; mate recognition ; reproductive isolation ; chemotaxonomoy ; phylogeny ; evolution ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The geometric isomers (E,E)-, (E,Z)-, (Z,E)-, and (Z,Z)-8,10-dodecadien-1-yl acetate were identified as sex pheromone components or sex attractants in the tribes Eucosmini and Grapholitini of the tortricid subfamily Olethreutinae. Species belonging to the more ancestral Tortricinae were not attracted. Each one isomer was behaviourally active in males ofCydia andGrapholita (Grapholitini), either as main pheromone compound, attraction synergist or attraction inhibitor. Their reciprocal attractive/antagonistic activity in a number of species enables specific communication with these four compounds.Pammene, as well as otherGrapholita andCydia responded to the monoenic 8- or 10-dodecen-1-yl acetates. Of the tribes Olethreutini and Eucosmini,Hedya, Epiblema, Eucosma, andNotocelia trimaculana were also attracted to 8,10-dodecadien-1-yl acetates, but several otherNotocelia to 10,12-tetradecadien-1-yl acetates. The female sex pheromones ofC. fagiglandana, C. pyrivora, C. splendana, Epiblema foenella andNotocelia roborana were identified. (E,E)- and (E,Z)-8,10-dodecadien-1-yl acetate are producedvia a commonE9 desaturation pathway inC. splendana. CallingC. nigricana andC. fagiglandana females are attracted to wingfanning males.
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  • 9
    ISSN: 1432-072X
    Keywords: Key words Fumarase ; Syntrophy ; Propionate ; oxidation ; Fumarate fermentation ; Anaerobic oxidation ; Iron-sulfur cluster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fumarase from the syntrophic propionate-oxidizing bacterium strain MPOB was purified 130-fold under anoxic conditions. The native enzyme had an apparent molecular mass of 114 kDa and was composed of two subunits of 60 kDa. The enzyme exhibited maximum activity at pH 8.5 and approximately 54° C. The K m values for fumarate and l-malate were 0.25 mM and 2.38 mM, respectively. Fumarase was inactivated by oxygen, but the activity could be restored by addition of Fe2+ and β-mercaptoethanol under anoxic conditions. EPR spectroscopy of the purified enzyme revealed the presence of a [3Fe-4S] cluster. Under reducing conditions, only a trace amount of a [4Fe-4S] cluster was detected. Addition of fumarate resulted in a significant increase of this [4Fe-4S] signal. The N-terminal amino acid sequence showed similarity to the sequences of fumarase A and B of Escherichia coli (56%) and fumarase A of Salmonella typhimurium (63%).
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  • 10
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    Journal of industrial microbiology and biotechnology 17 (1996), S. 151-158 
    ISSN: 1476-5535
    Keywords: bacteriocins ; colicins ; evolution ; ecology ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In this review we focus on the ecological and evolutionary forces that determine the frequency and diversity of colicins inEscherichia coli. To begin, we describe that this killing phenotype is ubiquitous inE. coli, with as many as 50% of the isolates from a population producing colicin toxins, and that each population sampled has its own unique distribution of the more than 20 known colicin types. Next, we explore the dynamics of colicinogeny, which exhibits a typical form of frequency dependence, where the likelihood of successful colicin invasion into a population increases as the initial density of colicinogenic cells increases. We then incorporate thoughts on the evolution of chromosomal resistance to colicins and describe how resistance might influence the dynamics of colicinogen invasion and maintenance and the resulting colicin diversity. The final section deals with a genetic and phylogenetic characterization of colicins and a discussion of the evolutionary mechanisms responsible for generating colicin diversity. In this final section we provide details of the different molecular mechanisms known to play a role in generating colicin diversity, including the two most dominant forces in colincin evolution: recombination and positive, deversifying, selection.
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  • 11
    ISSN: 1573-1561
    Keywords: Sex pheromone ; Idaea aversata ; Idaea straminata ; Idaea biselata ; (Z,Z)-9,11-tetradecadienyl acetate ; (Z,Z)-7,9-dodecadienyl acetate ; (Z,E)-7,9-dodecadienyl acetate ; Lepidoptera ; Geometridae ; electroantennography ; single cell recording ; biosynthesis ; phylogeny ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Pheromone compounds so far identified from most geometrid moths consist of all-Z diene, triene, or tetraene hydrocarbons with chain lengths of C17 to C21, and their monoepoxide derivatives biosynthesized from linoleic and linolenic acids. The present study reports the occurrence of olefinic acetates as sex pheromones in three species of Geometridae. (Z,Z)-9,11-tetradecadienyl acetate and (Z,Z)-7,9-dodecadienyl acetate found in female gland extracts ofIdaea aversata elicited significant responses from conspecific male antennae in gas chromatography with electroantennographic detection (GCEAD). In extracts ofI. straminata, (Z,Z)-7,9-dodecadienyl acetate, (E,Z)-7,9-dodecadienyl acetate, and (Z,Z)-7,9-dodecadienyl acetate were found, and the synthetic compounds elicited strong responses from conspecific male antennae. In the third species,I. biselata, only (Z,Z)-7,9-dodecadienyl acetate was found in the female extracts, and this compound elicited a strong EAD response from the conspecific male antenna. The identities of the pheromone components inI. aversata andI. straminata were further confirmed according to their characteristic ions after GC-MS analyses. Single sensillum recordings fromI. aversata showed two types of pheromone-detecting sensilla present on the male antenna. One type contained two receptor neurons, one of which was specifically tuned to (Z,Z)-9,11-tetradecadienyl acetate, the other to (Z,E)-9,11-tetradecadienyl acetate. A second type contained one neuron responding to (Z,Z)-7,9-dodecadienyl acetate. The two types were clearly different also with respect to external morphology, the former being considerably longer and having a larger base diameter. Also inI. straminata two physiological types of sensilla could be distinguished. One type contained two neurons, one of which responded to (Z,Z)-7,9-dodecadienyl acetate, the other to (Z,E)-9,11-tetradecadienyl acetate. The second type contained one neuron, responding to (Z,Z)-7,9-dodecadienyl acetate. No correlation between external morphology and physiological response of the investigated sensilla was observed inI. straminata. In field tests, a two-component blend containing (Z,Z)-9,11-tetradecadienyl acetate and (Z,Z)-7,9-dodecadienyl acetate in a ratio of 10:1 was attractive to males ofI. aversata. This two-component blend was also attractive to males ofI. straminata, but in a ratio of 1:1. High numbers of maleI. biselata were caught in traps baited with (Z,Z)-7,9-dodecadienyl acetate alone. The incorporation of deuterium labels into pheromone components after topical application of deuterium-labeled palmitic acid confirmed that the pheromone components ofI. aversata could be synthesized from this precursor, as has been previously observed for acetate pheromone components of many other moth species. Our results suggest that an evolutionary reversal back to the production of palmitic acid-derived pheromone components has occurred within the geometrid subfamily Sterrhinae.
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  • 12
    ISSN: 1573-4919
    Keywords: guanine nucleotide-binding proteins ; evolution ; phylogeny ; structure-function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract ADP-ribosylation factors (ARFs) are ∼20-kDa guanine nucleotide-binding proteins that are allosteric activators of the NAD:arginine ADP-ribosyltransferase activity of cholera toxin and appear to play a role in intracellular vesicular trafficking. Although the physiological roles of these proteins have not been defined, it has been presumed that each has a specific intracellular function. To obtain genetic evidence that each ARF is under evolutionary pressure to maintain its structure, and presumably function, rat ARF cDNA clones were isolated and their nucleotide and deduced amino acid sequences were compared to those of other mammalian ARFs. Deduced amino acid sequences for rat ARFs 1, 2, 3, 5 and 6 were identical to those of the known cognate human and bovine ARFs; rat ARF4 was 96% identical to human ARF4. Nucleotide sequences of both the untranslated as well as the coding regions were highly conserved. These results indicate that the ARF proteins are, as a family, extraordinarily well conserved across mammalian species. The unusually high degree of conservation of the untranslated regions is consistent with these regions having important regulatory roles and that individual ARFs contain structurally unique elements required for specific functions.
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  • 13
    ISSN: 1573-4935
    Keywords: Chemotaxis ; evolution ; oligopeptides ; Tetrahymena ; Dunaliella
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Chemotactic properties of amino acids (L-alanine, glycine and L-lysine) and their oligopeptides (10−6M) and binding sites to these ligands were investigated in two unicellular models, the heterotrophicTetrahymena pyriformis and the auxotrophicDunaliella salina. Chemotaxis ofDunaliella induced by simple amino acids and their derivatives demonstrated that binding sites (receptors) for food molecules are not only present in the membrane but are also able to induce their basic physiological response. InTetrahymena, substances with special molecular structure and properties (polar, hydrophilic character of the signal peptide chain)-5-L-Lys, 5-Glywere required for chemoattraction, other peptides tested, lacking the required structure, were repellent. Divergences in chemotaxis and binding assays of both species suggest that trends of functional and binding parameters do not run parallel at this level of evolution.
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  • 14
    ISSN: 1573-5028
    Keywords: carbon fixation ; chloroplasts ; evolution ; isoenzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cDNA encoding the Calvin cycle enzyme transketolase (TKL; EC 2.2.1.1) was isolated from Sorghum bicolor via subtractive differential hybridization, and used to isolate several full-length cDNA clones for this enzyme from spinach. Functional identity of the encoded mature subunit was shown by an 8.6-fold increase of TKL activity upon induction of Escherichia coli cells that overexpress the spinach TKL subunit under the control of the bacteriophage T7 promoter. Chloroplast localization of the cloned enzyme is shown by processing of the in vitro synthesized precursor upon uptake by isolated chloroplasts. Southern blot-analysis suggests that TKL is encoded by a single gene in the spinach genome. TKL proteins of both higher-plant chloroplasts and the cytosol of non-photosynthetic eukaryotes are found to be unexpectedly similar to eubacterial homologues, suggesting a possible eubacterial origin of these nuclear genes. Chloroplast TKL is the last of the demonstrably chloroplast-localized Calvin cycle enzymes to have been cloned and thus completes the isolation of gene probes for all enzymes of the pathway in higher plants.
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  • 15
    ISSN: 1573-4927
    Keywords: Bubalus ; tamaraw ; anoa ; cytochromeb ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The cytochromeb genes of all living species ofBubalus, including the river type and the swamp type of domestic buffaloes (Bubalus bubalis), were sequenced to clarify their phylogenetic relationships. These sequences were compared together with the African buffalo (Syncerus caffer) and banteng (Bos javanicus) sequences as an outgroup. Phylogenetic trees ofBubalus species based on the DNA sequences of the cytochromeb gene demonstrated that the tamaraw (Bubalus mindorensis), endemic to the Philippines, could be classified into the subgenusBubalus, not the subgenusAnoa. The divergence time between the lowland anoa (B. depressicornis) and the mountain anoa (B. quarlesi) was estimated at approximately 2.0 million years (Myr), which is almost the same as the coalescence time for theBubalus sequences. This large genetic distance supports the idea that the lowland anoa and the mountain anoa are different species. An unexpectedly large genetic distance between the river and the swamp type of domestic buffaloes suggests a divergence time of about 1.7 Myr, while the swamp type was noticed to have the closest relationship with the tamaraw (1.5 Myr). This result implies that the two types of domestic buffaloes have differentiated at the full species level.
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  • 16
    ISSN: 1573-5028
    Keywords: cDNA ; evolution ; p2 protein ; ribosome ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The nucleotide sequence of a full-length ribosomal P2 protein cDNA from maize was determined and used for a sequence comparison with the P2 and P1 proteins from other organisms. The integration of these data into a phylogenetic tree shows that the P proteins separated into the subspecies P1 and P2 before the eukaryotic kingdoms including plants developed from their ancestor.
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  • 17
    ISSN: 1573-5028
    Keywords: RNA editing ; tRNA editing ; chloroplast ; mitochondrion ; post-transcriptional modification ; initiation codon ; stop codon ; deamination ; evolution ; guide RNA ; transgenic plants ; plastid transformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the mitochondria and chloroplasts of higher plants there is an RNA editing activity responsible for specific C-to-U conversions and for a few U-to-C conversions leading to RNA sequences different from the corresponding DNA sequences. RNA editing is a post-transcriptional process which essentially affects the transcripts of protein coding genes, but has also been found to modify non-coding transcribed regions, structural RNAs and intron sequences. RNA editing is essential for correct gene expression: proteins translated from edited transcripts are different from the ones deduced from the genes sequences and usually present higher similarity to the corresponding non-plant homologues. Initiation and stop codons can also be created by RNA editing. RNA editing has also been shown to be required for the stabilization of the secondary structure of introns and tRNAs. The biochemistry of RNA editing in plant organelles is still largely unknown. In mitochondria, recent experiments indicate that RNA editing may be a deamination process. A plastid transformation technique showed to be a powerful tool for the study of RNA editing. The biochemistry as well as the evolutionary features of RNA editing in both organelles are compared in order to identify common as well as organelle-specific components.
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  • 18
    ISSN: 1573-5028
    Keywords: Calvin cycle ; sedoheptulose-1,7-bisphosphatase ; isoenzymes ; endosymbiosis ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Full-size cDNAs encoding the precursors of chloroplast fructose-1,6-bisphosphatase (FBP), sedoheptulose-1,7-bisphosphatase (SBP), and the small subunit of Rubisco (RbcS) from spinach were cloned. These cDNAs complete the set of homologous probes for all nuclear-encoded enzymes of the Calvin cycle from spinach (Spinacia oleracea L.). FBP enzymes not only of higher plants but also of non-photosynthetic eukaryotes are found to be unexpectedly similar to eubacterial homologues, suggesting a eubacterial origin of these eukaryotic nuclear genes. Chloroplast and cytosolic FBP isoenzymes of higher plants arose through a gene duplication event which occurred early in eukaryotic evolution. Both FBP and SBP of higher plant chloroplasts have acquired substrate specificity, i.e. have undergone functional specialization since their divergence from bifunctional FBP/SBP enzymes of free-living eubacteria.
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  • 19
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    Plant molecular biology 32 (1996), S. 685-692 
    ISSN: 1573-5028
    Keywords: evolution ; protein transport ; sec apparatus ; secA ; secY ; thylakoid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plastids possess a bacteria-like sec apparatus that is involved in protein import into the thylakoid lumen. We have analyzed one of the genes essential for this process, secY. A secY gene from the unicellular red alga Cyanidium caldarium was found to be transcriptionally active, demonstrating for the first time that secY is functional in a plastid. Unlike the situation seen in bacteria the C. caldarium gene is transcribed monocistronically, despite the fact that it is part of a large ribosomal gene cluster that resembles bacterial spc operons. A molecular phylogeny is presented for 8 plastid-encoded secY genes, four of which have not been published yet. In this analysis plastid secY genes fall into two classes. One of these, comprising of genes from multicellular red algae and Cryptophyta, clusters in a neighbour-joining tree with a cyanobacterial counterpart. Separated from the aforesaid are secY genes from Chromophyta, Glaucocystophyta and a unicellular red alga. All plastid and cyanobacterial sequences are located on the same branch, separated from bacterial homologues. We postulate that the two classes of secY genes are paralogous, i.e. their gene products are involved in different protein translocation processes. Based on this assumption a model for the evolution of the plastid sec apparatus is presented.
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  • 20
    ISSN: 1573-4927
    Keywords: genome mapping ; evolution ; homology ; polymerase chain reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We are developing a genetic map of the dog based partly upon markers contained within known genes. In order to facilitate the development of these markers, we have used polymerase chain reaction (PCR) primers designed to conserved regions of genes that have been sequenced in at least two species. We have refined the method for designing primers to maximize the number that produce successful amplifications across as many mammalian species as possible. We report the development of primer sets for 11 loci in detail:CFTR, COL10A1, CSFIR, CYP1A1, DCN1, FES, GHR, GLB1, PKLR, PVALB, andRB1. We also report an additional 75 primer sets in the appendices. The PCR products were sequenced to show that the primers amplify the expected canine genes. These primer sets thus define a class of gene-specific sequence-tagged sites (STSs). There are a number of uses for these STSs, including the rapid development of various linkage tools and the rapid testing of genomic and cDNA libraries for the presence of their corresponding genes. Six of the eleven gene targets reported in detail have been proposed to serve as “anchored reference loci” for the development of mammalian genetic maps [O'Brien, S. J.,et al., Nat. Genet. 3:103, 1993]. The primer sets should cover a significant portion of the canine genome for the development of a linkage map. In order to determine how useful these primer sets would be for the other genome projects, we tested the 11 primer sets on the DNA from species representing five mammalian orders. Eighty-four percent of the gene-species combinations amplified successfully. We have named these primer sets “universal mammalian sequence-tagged sites” because they should be useful for many mammalian genome projects.
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  • 21
    ISSN: 1573-4927
    Keywords: genome mapping ; evolution ; homology ; polymerase chain reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We are developing a genetic map of the dog based partly upon markers contained within known genes. In order to facilitate the development of these markers, we have used polymerase chain reaction (PCR) primers designed to conserved regions of genes that have been sequenced in at least two species. We have refined the method for designing primers to maximize the number that produce successful amplifications across as many mammalian species as possible. We report the development of primer sets for 11 loci in detail:CFTR, COL10A1, CSFIR, CYP1A1, DCN1, FES, GHR, GLB1, PKLR, PVALB, andRB1. We also report an additional 75 primer sets in the appendices. The PCR products were sequenced to show that the primers amplify the expected canine genes. These primer sets thus define a class of gene-specific sequence-tagged sites (STSs). There are a number of uses for these STSs, including the rapid development of various linkage tools and the rapid testing of genomic and cDNA libraries for the presence of their corresponding genes. Six of the eleven gene targets reported in detail have been proposed to serve as “anchored reference loci” for the development of mammalian genetic maps [O'Brien, S. J.,et al., Nat. Genet. 3:103, 1993]. The primer sets should cover a significant portion of the canine genome for the development of a linkage map. In order to determine how useful these primer sets would be for the other genome projects, we tested the 11 primer sets on the DNA from species representing five mammalian orders. Eighty-four percent of the gene-species combinations amplified successfully. We have named these primer sets “universal mammalian sequence-tagged sites” because they should be useful for many mammalian genome projects.
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  • 22
    ISSN: 1573-5028
    Keywords: developmental regulation ; elongation factor ; evolution ; gene expression ; rhodophyte, sporophyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The life cycle of the red alga Porphyra purpurea alternates between two morphologically distinct phases: a shell-boring, filamentous sporophyte and a free-living, foliose gametophyte. From a subtracted cDNA library enriched for sporophyte-specific sequences, we isolated a cDNA encoding an unusual elongation factor 1α (EF-1α) that is expressed only in the sporophyte. A second EF-1α gene that is expressed equally in the sporophyte and the gametophyte was isolated from a genomic library. These are the only EF-1α genes detectable in P. purpurea. The constitutively expressed gene encodes and EF-1α very similar to those of most eukaryotes. However, the sporophyte-specific EF-1α is one of the most divergent yet described, with nine insertions or deletions ranging in size from 1 to 26 amino acids. This is the first report of a developmental stage-specific EF-1α outside of the animal kingdom and suggests a fundamental role for EF-1α in the developmental process.
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    ISSN: 1573-5028
    Keywords: carboxysomes ; evolution ; ribulose 1,5-bisphosphate carboxylase/oxygenase ; Synechococcus
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    Notes: Abstract Marine phycoerythrin-containing cyanobacteria are major contributors to the overall productivity of the oceans. The present study indicates that the structural genes of the carbon assimilatory system are unusually arranged and possess a unique primary structure compared to previously studied cyanobacteria. Southern blot analyses of Synechococcus sp. strain WH7803 chromosomal DNA digests, using the ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) large subunit gene from Synechococcus sp. strain PCC6301 as a heterologous probe, revealed the presence of a 6.4 kb HindIII fragment that was detectable at only low stringency. Three complete open reading frames (ORFs) were detected within this fragment. Two of these ORFs potentially encode the Synechococcus sp. strain WH7803 rbcL and rbcS genes. The third ORF, situated immediately upstream from rbcL, potentially encodes a homologue of the ccmK gene from Synechococcus sp. strain PCC7942. The deduced amino acid sequences of each of these ORFs are more similar to homologues among the β/γ purple bacteria than to existing cyanobacterial homologues and phylogenetic analysis of the Rubisco large and small subunit sequences confirmed an unexpected relationship to sequences from among the β/γ purple bacteria. This is the first instance in which the possibility has been considered that an operon encoding three genes involved in carbon fixation may have been laterally transferred from a purple bacterium. Analysis of mRNA extracted from cells grown under diel conditions indicated that rbcL, rbcS and ccmK were regulated at the transcriptional level; specifically rubisco transcripts were highest during the midday period, decreased at later times during the light period and eventually reached a level where they were all but undetectable during the dark period. Primer extension analysis indicated that the ccmK, rbcL and rbcS genes were co-transcribed.
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    Plant molecular biology 32 (1996), S. 923-936 
    ISSN: 1573-5028
    Keywords: PEPC ; C3 metabolism ; gene expression ; evolution ; gymnosperm ; Picea abies
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    Topics: Biology
    Notes: Abstract Phosphoenolpyruvate carboxylase (PEPC) genes and cDNA sequences have so far been isolated from a broad range of angiosperm but not from gymnosperm species. We constructed a cDNA library from seedlings of Norway spruce (Picea abies) and identified cDNAs coding for PEPC. A full-length PEPC cDNA was sequenced. It consists of 3522 nucleotides and has an open reading frame (ORF) that encodes a polypeptide (963 amino acids) with a molecular mass of 109 551. The deduced amino acid sequence revealed a higher similarity to the C3-form PEPC of angiosperm species (86–88%) than to the CAM and C4 forms (76–84%). The putative motif (Lys/Arg-X-X-Ser) for serine kinase, which is conserved in all angiosperm PEPCs analysed so far, is also present in this gymnosperm sequence. Southern blot analysis of spruce genomic DNA under low-stringency conditions using the PEPC cDNA as a hybridization probe showed a complex hybridization pattern, indicating the presence of additional PEPC-related sequences in the genome of the spruce. In contrast, the probe hybridized to only a few bands under high-stringency conditions. Whereas this PEPC gene is highly expressed in roots of seedlings, a low-level expression can be detected in cotyledons and adult needles. A molecular phyiogeny of plant PEPC including the spruce PEPC sequence revealed that the spruce PEPC sequence is clustered with monocot and dicot C3-form PEPCs including the only dicot C4 form characterized so far.
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    Plant systematics and evolution 201 (1996), S. 149-162 
    ISSN: 1615-6110
    Keywords: Colchicaceae ; Androcymbium ; Allozymes ; morphology ; endemism ; evolution ; conservation
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    Notes: Abstract Narrow endemism is a poor predictor of genetic potential in the six taxa that conform theAndrocymbium gramineum complex, as shown by the unexpectedly high values of variability associated with ten allozymic loci and 13 biometrical variables. Although both levels are shown not to be correlated, variability is always concentrated within populations. This result, together with environmental, reproductive and historical data strongly suggests differentiation in local isolates, where changes can be quickly assimilated by stochastic processes. A key implication for conservation is that sampling within the largest population will save effort while neglecting only very low frequency alleles.
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    Plant systematics and evolution 200 (1996), S. 1-11 
    ISSN: 1615-6110
    Keywords: Juncaceae ; Luzula sect.Luzula ; Taxonomy ; karyotypes ; evolution ; Flora of Spain
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    Notes: Abstract A survey ofLuzula sect.Luzula (Juncaceae) with data on karyology, morphology and distribution in the Iberian Peninsula is provided. Names published from the region are evaluated.L. campestris subsp.campestris, L. c. subsp.nevadensis, L. sudetica, L. ×heddae, L. congesta, L. ×danica, L. alpina, L. multiflora, andL. multiflora s. l. are discussed. A diploid taxon with agmatoploid karyotype, morphologically close toL. multiflora andL. alpina, has been revealed and is described asL. multiflora subsp.monticola. L. campestris subsp.iberica has been relegated to the synonymy of subsp.campestris, L. c. subsp.carpetana was found to belong toL. multiflora s. l.
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    Plant systematics and evolution 199 (1996), S. 17-32 
    ISSN: 1615-6110
    Keywords: Apiaceae ; Umbelliferae ; Anthriscus ; Taxonomy ; phylogeny ; evolution ; ecological radiation
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    Notes: Abstract Species boundaries and phylogenetic relationships of 17 taxa ofAnthriscus (Apiaceae), with special emphasis on the critical sect.Cacosciadium, were explored using morphological data with principal component analysis, phenetics, and phylogenetics. The analyses did not provide satisfactory resolution of taxa from sect.Cacosciadium and only four species were retained. The total number of species was reduced to nine. Sect.Cacosciadium is distinguished by only two synapomorphies while sects.Anthriscus andCaroides are better supported. Present geographic and ecological variation suggests that the radiation ofAnthriscus occurred through divergence of peripheral isolated populations adapting to different habitats: high montane meadows and screes, shady climax forests, and seasonally dry habitats at lower altitudes. The adaptive significance of particular morphological traits is discussed.
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    Plant systematics and evolution 202 (1996), S. 121-135 
    ISSN: 1615-6110
    Keywords: Rubiaceae ; Galium ; Allozyme variation ; systematics ; ploidy level ; evolution
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    Topics: Biology
    Notes: Abstract Allozyme variation at 11 loci (with 37 alleles) was studied electrophoretically in seven outbreeding, closely related diploid and tetraploid taxa, seven from sect.Leptogalium and two from sect.Leiogalium. Whereas the sections are clearly distinct by several different alleles, aggregates, species and subspecies differ only in the frequency or presence/absence of common alleles. The resulting dendrogram suggests phylogenetic relationships and is supported by other multidisciplinary evidence. Tetraploids have originated independently in several groups, and there is evidence for tetrasomic inheritance and thus for autopolyploidy in spite of normal meiotic bivalent pairing and partly suspected hybrid origin. Tetraploids differ from related diploids only little in number of alleles and expected heterozygosity within populations, but clearly exhibit higher numbers of genotypes. This often corresponds to their greater morphological variability, increased adaptive flexibility, and better colonizing capacity compared to related diploids.
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    Plant systematics and evolution 203 (1996), S. 111-142 
    ISSN: 1615-6110
    Keywords: Pelargonium ; sect.Hoarea ; Chromosomes ; B chromosomes ; Robertsonian translocation ; centric fusion ; evolution ; systematics
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    Notes: Abstract Chromosome numbers of 65 species of sect.Hoarea have been determined. These show three basic chromosome numbers, x = 11, 10 and 9. Only a few species are tetraploid. In five species both diploid and tetraploid cytotypes are reported. Several cases of deviations in chromosome numbers and cytological abnormalities were found, most of these being related to the presence of B chromosomes that occur in eight species. Evidence is presented to suggest that the basic chromosome numbers of x = 10 and x = 9 are derived from x = 11 by centric fusion. Although variation in basic chromosome number withinPelargonium has been the subject of detailed study, this is the first time that evidence has been found for a mechanism of change in basic number, that of centric fusion by Robertsonian translocation. For the species of sect.Hoarea with x = 9, where the evidence for Robertsonian translocation is greatest, this process has probably taken place quite recently. In contrast to results from other sections of the genusPelargonium, the three different basic numbers of sect.Hoarea do not contradict its delimitation as a natural taxon.
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    Biology and philosophy 11 (1996), S. 21-31 
    ISSN: 1572-8404
    Keywords: Morality ; evolution ; justification ; objectivity
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    Topics: Biology , Philosophy
    Notes: Abstract A familiar position regarding the evolution of ethics is that biology can explain the origin of morals but that in doing so it removes the possibility of their having objective justification. This position is set fourth in detail in the writings of Michael Ruse (1986, 1987, 1989, 1990a, 1990b) but it is also taken by many others, notably, Jeffrie Murphy (1982), Andrew Oldenquist (1990), and Allan Gibbard (1990), I argue the contrary view that biology provides a justification of the existence of morals which is objective in the sense of being independent of people's moral views and their particular desires and preferences. Ironically, my argument builds on the very premises which are supposed to undermine the objectivity of morals. But my argument stops short of claiming that biology can give us a basis for justifying some particular system of morals. Drawing on an analogy with social contract theory, I offer a general reason why this more ambitious project cannot be expected to succeed if the argument is pursued along the same lines. Finally, I give reasons why the possibility of objective justification for a particular morality cannot be ruled out in general on evolutionary grounds.
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    Biology and philosophy 11 (1996), S. 33-65 
    ISSN: 1572-8404
    Keywords: Background assumptions ; Darwinism ; evolution ; Newtonian dynamics ; nonequilibrium thermodynamics ; nonlinear dynamics ; probability revolution ; selection ; self-organization ; systems dynamics
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    Topics: Biology , Philosophy
    Notes: Abstract The Darwinian concept of natural selection was conceived within a set of Newtonian background assumptions about systems dynamics. Mendelian genetics at first did not sit well with the gradualist assumptions of the Darwinian theory. Eventually, however, Mendelism and Darwinism were fused by reformulating natural selection in statistical terms. This reflected a shift to a more probabilistic set of background assumptions based upon Boltzmannian systems dynamics. Recent developments in molecular genetics and paleontology have put pressure on Darwinism once again. Current work on self-organizing systems may provide a stimulus not only for increased problem solving within the Darwinian tradition, especially with respect to origins of life, developmental genetics, phylogenetic pattern, and energy-flow ecology, but for deeper understanding of the very phenomenon of natural selection itself. Since self-organizational phenomena depend deeply on stochastic processes, self-organizational systems dynamics advance the probability revolution. In our view, natural selection is an emergent phenomenon of physical and chemical selection. These developments suggest that natural selection may be grounded in physical law more deeply than is allowed by advocates of the autonomy of biology, while still making it possible to deny, with autonomists, that evolutionary explanations can be modeled in terms of a deductive relationship between laws and cases. We explore the relationship between, chance, self-organization, and selection as sources of order in biological systems in order to make these points.
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    Biology and philosophy 11 (1996), S. 193-214 
    ISSN: 1572-8404
    Keywords: Adaptationism ; avatars ; competition ; explanation ; evolution ; macroevolution ; optimality ; reductionism ; species selection ; species sorting
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    Topics: Biology , Philosophy
    Notes: Abstract The ontological dependence of one domain on another is compatible with the explanatory autonomy of the less basic domain. That autonomy results from the fact that the relationship between two domains can be very complex. In this paper I distinguish two different types of complexity, two ways the relationship between domains can fail to be transparent, both of which are relevant to evolutionary biology. Sometimes high level explanations preserve a certain type of causal or counterfactual information which would be lost at the lower level; I argue that this is central to the proper understanding of the adaptationist program. Sometimes high level kinds are multiply realised by lower level kinds: I argue that this is central to the understanding of macroevolution.
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    Biology and philosophy 11 (1996), S. 215-244 
    ISSN: 1572-8404
    Keywords: Classes ; classification ; evolution ; Buffon ; Darwin ; Ghiselin ; individuality ; ordering ; concept of species
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    Topics: Biology , Philosophy
    Notes: Abstract Since the 1970s, there has been a tremendous amount of literature on Ghiselin's proposal that “species are individuals”. After recalling the origins and stakes of this thesis in contemporary evolutionary theory, I show that it can also be found in the writings of the French naturalist Buffon in the 18th Century. Although Buffon did not have the conception that one species could be derived from another, there is an interesting similarity between the modern argument and that of Buffon regarding the “individuality of species’. The analogy is strong enough to force us to recognize that genuine evolutionary (or Darwinian) questions might be of secondary importance in the discussion. In consequence, the third section of the paper proposes an alternative schema for the “logical structure” of the Darwinian concept of species. Darwin distinguished the problem of the designation of a concrete species, and the problem of its signification of species within his theory of descent? The resulting notion of species involves a logical structure based on the fusion of the logical operations of classification and ordering. The difficulty — and interest — is that this interpretation of species does not entail any precise operational definition of species; it can only tell us what the ultimate signification of classification is within the theory of descent with modification through natural selection.
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    Biology and philosophy 11 (1996), S. 377-403 
    ISSN: 1572-8404
    Keywords: development ; developmental systems ; gene ; genetic information ; evolution ; information ; inheritance ; interactor ; Lamarck ; Meme ; replicator ; selection ; unit of selection ; vehicle ; Weismann
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    Topics: Biology , Philosophy
    Notes: Abstract This paper evaluates and criticises the developmental systems conception of evolution and develops instead an extension of the “gene's eye” conception of evolution. We argue (i) Dawkin's attempt to segregate developmental and evolutionary issues about genes is unsatisfactory. On plausible views of development it is arbitrary to single out genes as the units of selection. (ii) The genotype does not carry information about the phenotype in any way that distinguishes the role of the genes in development from that other factors. (iii) There is no simple and general causal criterion which distinguishes the role of genes in development and evolution. (iv) There is, however, an important sense in which genes but not every other developmental factor represent the phenotype. (v) The idea that genes represent features of the phenotype forces us to recognise that genes are not the only, or almost the only, replicators. Many mechanisms of replication are involved in both development and evolution. (vi) A conception of evolutionary history which recognises both genetic and non-genetic replicators, lineages of replicators and interactors has advantages over both the radical rejection of the replicator/interactor distinction and the conservative restriction of replication to genetic replication.
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    Biology and philosophy 11 (1996), S. 405-420 
    ISSN: 1572-8404
    Keywords: species ; evolution ; natural selection ; gradualism ; punctuated equilibria ; variation ; Lamarck ; Darwin
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    Topics: Biology , Philosophy
    Notes: Abstract Species are thought by many to be important units of evolution. In this paper, I argue against that view. My argument is based on an examination of the role of species in the synthetic theory of evolution. I argue that if one adopts a gradualist view of evolution, one cannot make sense of the claim that species are “units” in the minimal sense needed to claim that they are units of evolution, namely, that they exist as discrete entities over time. My second argument is directed against an appeal to Eldredge and Gould's theory of punctuated equilibria to support the claim that species are units of evolution. If one adopts their view, it may be possible to identify discrete temporal entities that can plausibly be termed ‘species’, but there is no reason to claim that those entities are “units of evolution”. Thus, on two plausible interpretations of the role of natural selection in the process of evolution, species are of no special importance. I then consider some of the reasons why species have been thought to be important evolutionary units by many contemporary evolutionary biologists. Finally, I discuss briefly the implications of this conclusion for evolutionary biology.
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    Biology and philosophy 11 (1996), S. 543-559 
    ISSN: 1572-8404
    Keywords: Creationism ; evidence ; evolution ; naturalism ; Phillip Johnson ; scientific methodology
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    Topics: Biology , Philosophy
    Notes: Abstract Phillip Johnson claims that Creationism is a better explanation of the existence and characteristics of biological species than is evolutionary theory. He argues that the only reason biologists do not recognize that Creationist's negative arguments against Darwinism have proven this is that they are wedded to a biased ideological philosophy —Naturalism — which dogmatically denies the possibility of an intervening creative god. However, Johnson fails to distinguish Ontological Naturalism from Methodological Naturalism. Science makes use of the latter and I show how it is not dogmatic but follows from sound requirements for empirical evidential testing. Furthermore, Johnson has no serious alternative type of positive evidence to offer for Creationism, and purely negative argumentation, despite his attempt to legitimate it, will not suffice.
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    Biology and philosophy 12 (1996), S. 51-71 
    ISSN: 1572-8404
    Keywords: philosophy of mind ; ethics ; animal pain ; Peter Carruthers ; consciousness ; evolution
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    Topics: Biology , Philosophy
    Notes: Abstract In a series of works, Peter Carruthers has argued for the denial of the title proposition. Here, I defend that proposition by offering direct support drawn from relevant sciences and by undercutting Carruthers‘ argument. In doing the latter, I distinguish an intrinsic theory of consciousness from Carruthers‘ relational theory of consciousness. This relational theory has two readings, one of which makes essential appeal to evolutionary theory. I argue that neither reading offers a successful view.
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    Hydrobiologia 325 (1996), S. 1-30 
    ISSN: 1573-5117
    Keywords: subterranean Cladocera ; history ; ecology ; adaptation ; evolution ; biogeography
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    Topics: Biology
    Notes: Abstract A synthesis of current knowledge of the Cladocera living in non-surface waters is provided. For all 94 species and subspecies recorded (Dec. 1994) we give information on their ranges, ecological characteristics, and a review of literature data. We also give a historic survey of the development of concepts, identify categories among groundwater-dwelling species, and discuss their adaptations and the evolutionary lines present. Of the estimated total of c. 450 non-marine Cladocera of the world, c. 20% may occur in underground aquatic habitats, but true groundwater forms (stygobionts or stygobites) are relatively few, possibly not more than 10 species (c. 2.5% of the total). This number may increase, as attention is given to subterranean habitats outside Europe.
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    Hydrobiologia 320 (1996), S. 15-26 
    ISSN: 1573-5117
    Keywords: Crustacea ; diapause ; photoperiod responses ; evolution
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    Topics: Biology
    Notes: Abstract Definitions of diapause and of the three types of diapause (embryonal, larval and imaginal) as they apply to the Crustacea are given and the distribution of the types among different orders of crustaceans is discussed. A special role of diapause as a way to escape competition among ecologically similar species is noted and the significance of photoperiod responses as a pace-maker of the biorhythmical function of diapause for a wide range of species is demonstrated. A common unspecific regression for the description of oxygen consumption with duration of diapause in crustaceans of different sizes, different orders and different types of diapause is suggested. A special significance of embryonal diapause for the adaptation of palaeo-, meso- and neolimnic species of crustaceans that migrated from the sea into inland waterbodies is postulated.
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    Hydrobiologia 334 (1996), S. 277-285 
    ISSN: 1573-5117
    Keywords: leech ; oligochaete ; parasite ; evolution ; phylogeny
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    Topics: Biology
    Notes: Abstract Powerful tests of adaptational hypotheses can be made in the context of well-supported cladograms by investigating the most parsimonious transformation of intrinsic or extrinsic factors to explain their distribution across taxa in a cladogram. Such tests are used here to discover patterns of life-history evolution in leeches; in particular in relation to exploitation of terrestrial and aquatic habitats, parental care and resource utilization. Moreover, the relationships among leeches, acanthobdellids and branchiobdellids is reaffirmed as is their collective placement within the oligochaetes.
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    Hydrobiologia 320 (1996), S. 1-14 
    ISSN: 1573-5117
    Keywords: diapause ; freshwater Crustacea ; antiquity ; diversity ; evolution
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    Topics: Biology
    Notes: Abstract After a brief historical review of the discovery of diapause in freshwater crustaceans, its dramatic nature in certain cyclopoid copepods, in which diapausing individuals may occur at densities of 〉 106 per m2, is used to illustrate the enormous ecological significance of the phenomenon. Some of the problems presented by dispause in cyclopoid copepods are noted, including the different behaviour in different lakes of what appears to be a single species. Different physiological cues or different genetic endowments are clearly involved. The wider incidence of diapause in freshwater copepods and ostracods is noted. Among freshwater crustaceans it it the Branchiopoda that have universally adopted diapause, always at the egg stage. Even such an ancient order as the Anostraca, perhaps the most primitive of all crustaceans, produces elaborately constructed resting eggs that are capable of cryptobiosis, can remain viable in a dry state for long periods, and can tolerate extreme conditions. The nature of branchiopod resting eggs is briefly reviewed. Of these, only those of the Anomopoda are protected by containers derived from the parental carapace. These are mechanically complex in the most advanced species but, as shown by fossils, are extremely ancient structures. Factors initiating the onset and termination of diapause in branchiopods are briefly noted, and the process of hatching of resting eggs is outlined.
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  • 42
    ISSN: 1573-5117
    Keywords: Larval development ; chthamalid barnacle ; Octomeris sulcata ; food preference ; evolution ; gnathobase
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    Notes: Abstract Embryos obtained from gravid adults of the chthamalid barnacle Octomeris sulcata Nilsson-Cantell from Japan and Korea were cultured through six naupliar stages to the cyprid and juvenile barnacle stage in laboratory conditions, fed either the diatom Skeletonema costatum (Grev.) Cleve or the dinoflagellate Prorocentrum minimum (Pavillard) Schiller. The nauplii were planktotrophic and, depending on diet, reached the cyprid stage 9 or 17 days after hatching in individual cultures at 22 °C with 24 h illumination. The survival rate was higher and the duration of the naupliar stages was shorter when fed P. minimum rather than S. costatum. This is probably due to the presence of feathered setae on the antennae. Feathered or plumose setae in nauplii of different cirripede taxa are apparently linked to the type of phytoplankton in the seas when these taxa first evolved. The larval stages of O. sulcata are described, and morphological differences between larvae reared from Japanese andKorean adults are compared. The polygonal cephalic shield and unilobed labrum, a pair of posterior shield spines after naupliar stage IV, feathered setae and a hispid seta on the coxa of the antenna, a cuspidate seta on the mandible, and the gnathobase of the antenna are important in distinguishing the nauplii of this species from other species, including Chthamalidae.
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    ISSN: 1573-6849
    Keywords: chromosome ; evolution ; FISH ; intrachromosomal rearrangements ; phylogeny ; subregional chromosome painting
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    Notes: Abstract We have usedAlu polymerase chain reaction generated probes from rearranged human/rodent somatic cell hybrids for fluorescencein situ hybridization and comparative mapping of some intrachromosomal changes in the karyotypes of great apes (Pan troglodytes, P. paniscus, Gorilla gorilla Pongo pygmaeus), a gibbon (Hylobates lar), and an Old World monkey (Macaca fuscata). Probes containing chromosomes 2 and 18 fragments confirmed inversions already suggested by the banding pattern of great ape homologues. However, a chromosome 3 fragment showed complex rearrangements in the gibbon and macaque karyotype which were previously not well defined from banding. ‘Subchromosomal painting’ will allow the identification of intrachromosomal changes on the basis of DNA homology and provides a powerful method to study karyological and genomic evolution.
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    ISSN: 1573-3297
    Keywords: Heterosis ; nest-building behavior ; Mus domesticus ; selection ; evolution
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    Topics: Biology , Psychology
    Notes: Abstract Replicate high-selected, control, and low-selected lines were crossed at generation 46 of bidirectional selection for thermoregulatory nest-building behavior. Previous analysis of the lines at their limits had revealed multiple responses to uniform selection, where each of the four selected lines responded differently to reverse selection (Laffan, 1989). The reciprocal F1 crosses showed significant heterosis for nest-building behavior compared to the contemporaneous generations of the parental lines. This pattern of heterosis in all three crosses is consistent with the finding that nest-building behavior in each of the four replicate lines had a different genetic basis, in spite of the phenotypic similarity between the two replicate lines in the high and low direction of nesting. This heterosis effect and the larger number of young weaned in all three crosses compared to their respective contemporaneous generation of the parental lines also support earlier findings that larger nests are closely related to fitness.
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    ISSN: 1573-8477
    Keywords: common environment ; reciprocal transplant ; genetic differentiation ; phenotypic plasticity ; trophic polymorphism ; evolution ; specialization ; fish
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    Topics: Biology
    Notes: Summary Adaptive variation can exist at a variety of scales in biological systems, including among species, among local populations of a single species and among individuals within a single population. Trophic or resource polymorphisms in fishes are a good example of the lowest level of this hierarchy. In lakes without bluegill sunfish (Lepomis macrochirus), pumpkinseed sunfish (Lepomis gibbosus) can be trophically polymorphic, including a planktivorous limnetic form found in the pelagic habitat, in addition to the usual benthic form found in the littoral zone. In this paper we examine the degree to which morphological differences between the two forms are caused by genetic differences versus phenotypic plasticity. Adults from pelagic and littoral sites in Paradox Lake, NY, were bred separately and their progeny were raised in cages both in the open water and shallow water habitats of an artificial pond. The experimental design permitted two tests of genetic differences between the breeding stocks (in open and shallow water cages, respectively) and two tests of phenotypic plasticity (in the limnetic and benthic offspring, respectively). Limnetic progeny were more fusiform than benthic progeny raised in the same habitat. In addition, progeny of both stocks displayed limnetic-type characteristics when raised in the open water and benthic-type characteristics in the shallow water. Thus, genetic differences and phenotypic plasticity both contributed to the trophic polymorphism. Phenotypic plasticity and genetic differentiation accounted for 53 and 14%, respectively, of the variation in morphology. This study addresses the nature of subtle phenotypic differences among individuals from a single population that is embedded within a complex community, a condition that is likely to be the norm for most natural populations, as opposed to very large differences that have evolved in relatively few populations that reside in species-poor environments.
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  • 46
    ISSN: 1573-6830
    Keywords: tyrosine hydroxylase immunocytochemistry ; spinal cord ; chick embryo ; dopamine immunocytochemistry ; evolution ; CSF-contacting neurons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. The development of tyrosine hydroxylase-immunoreactive (TH-IR) neurons was examined in the spinal cord of the chick embryo and hatchling. 2. Two groups of TH-IR cells are described, both of which appear to reach their full complement in number relatively late in embryonic development. One group is comprised of numerous cells located ventral to the central canal which make direct contact with the lumen of the canal. The other group consists of large multipolar neurons that reside in the dorsal horn, more commonly along the outer margin of the gray matter within lamina I and II, and less frequently deeper in the dorsal horn within medial portions of laminae V, VI or VII. 3. TH-IR cells ventral to the central canal in the chick are comparable in location to dopamine (DA)-containing spinal cord cells in lower vertebrate species. In contrast, the dorsally-suited TH-IR cells in the chick are known only to occur in similar positions in higher vertebrates. Therefore, the chick is novel in that the presence ofboth groups of TH-IR cells appearing together in significant numbers within the spinal cord has not been shown in any other species studied to date. 4. The TH-containing cells in the chick cord do not appear to contain the catecholamine biosynthesis enzymes, DBH or PNMT. Moreover, using anti-DA immunocytochemistry, neither group of TH-IR cells demonstrated detectable levels of DA in control animals nor in animals pretreated with inhibitors of MAO (MAO-I). 5. However, a difference was noted though between the two TH-IR cell groups in terms of their responses to exogenously supplied L-DOPA, the immediate precursor to DA. With the administration of L-DOPA and a MAO-I to chick hatchlings, cells in the region ventral to the central canal stained intensely for DA. In contrast, the same treatment failed to produce DA-immunoreactive cells in the dorsal horn. 6. One reasonable hypothesis for these results is that the TH-IR cells ventral to the central canal contain an active form of AADC, the enzyme that converts L-DOPA to DA. With this interpretation, if these cells can produce DA from L-DOPA, yet do not appear to synthesize DA endogenously, it would appear that the TH enzyme contained in these cells occurs in aninactive form. Whether the TH enzyme in the dorsally located immunoreactive cells is also inactive is uncertain since it remains unclear whether they contain AADC.
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  • 47
    ISSN: 1573-6849
    Keywords: Ctenomys ; evolution ; heterochromatin ; rodents ; satellite DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The genus of subterranean rodentsCtenomys presents the widest range of variability in diploid number among mammals (from2n=10 to2n=70). In Uruguay, this variability is observed in karyotypes with2n=44, 50 or 58 and two geographically isolated populations with 70 chromosomes but different karyotypic structure. The last three populations were analyzed in the present study. They present a satellite DNA, which was isolated from genomic DNA afterAlul digestion.In situ hybridization showed that this satellite DNA is located in the centromeric region of a few chromosomes, coincident with Hoechst 33258 staining and C-banding patterns. A similar satellite DNA was detected in Argentinian species of this genus. We established that, in spite of differences in number of positive heterochromatic blocks per karyotype, the C value is the same in the three populations studied. The nature and possible evolutionary path of this repeated DNA is discussed.
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  • 48
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    Genetica 98 (1996), S. 149-160 
    ISSN: 1573-6857
    Keywords: Drosophila melanogaster ; evolution ; mosaics ; mutation ; premeiotic clusters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In contrast to the common assumption that each new mutant results from a unique, independent mutation event, clusters of identical premeiotic mutant alleles are common. Clusters can produce large numbers of related individuals carrying identical copies of the same new genetic change. By entering the gene pool in multiple copies at one time, clusters can influence fundamental processes of population genetics. Here we report evidence that clusters can increase the arrival and fixation probabilities and can lengthen the average time to extinction of new mutations. We also suggest it may be necessary to reconsider other fundamental elements of population genetic theory.
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  • 49
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    Journal of mammalian evolution 3 (1996), S. 261-279 
    ISSN: 1573-7055
    Keywords: Cartesian ; transformation ; splines ; rhinoceros ; skull ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cartesian transformation, applied as a landmark morphometric method, is used to investigate some of the evolutionary shape changes leading to the skulls of the modern rhinoceroses. The early Oligocene genusSubhyracodon serves as the primitive shape from which the extant genera (Dicerorhinus, Rhinocerso, Diceros, andCeratotherium) have been transformed. Coordinate data for 21 landmarks, defined in lateral view, are analyzed by the computer program Thinplate Splines. Each of the four transformations are interpreted separately as shape change fromSubhyracodon. Computed results forRhinoceros are also compared with previous results obtained by visual interpretation (the classic method). Among the extant genera,Ceratotherium andRhinoceros have the most derived shapes and are opposites with respect to orientation of the occiput and relative size of the mandible angle. The significance of these foci of change is discussed in terms of the functions of the masseter and posterior temporalis muscles. In head positions associated with feeding on short vs. tall grasses, the two skull shapes are consistent with a role for these muscles in support of a large mandible against gravity. This common factor may help to explain both shapes.
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  • 50
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    Journal of industrial microbiology and biotechnology 17 (1996), S. 137-150 
    ISSN: 1476-5535
    Keywords: bacteria ; species concepts ; genetics ; diversity ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A discussion of the species problem in modern evolutionary biology serves as the point of departure for an exploration of how the basic science aspects of this problem relate to efforts to map bacterial diversity for practical pursuits—for prospecting among the bacteria for useful genes and gene-products. Out of a confusing array of species concepts, the Cohesion Species Concept seems the most appropriate and useful for analyzing bacterial diversity. Techniques of allozyme analysis and DNA fingerprinting can be used to put this concept into practice to map bacterial genetic diversity, though the concept requires minor modification to encompass cases of complete asexuality. Examples from studies of phenetically definedBacillus species provide very partial maps of genetic population structure. A major conclusion is that such maps frequently reveal deep genetic subdivision within the phenetically defined specles; divisions that in some cases are clearly distinct genetic species. Knowledge of such subdivisions is bound to make prospecting within bacterial diversity more effective. Under the general concept of genetic cohesion a hypothetical framework for thinking about the full range of species conditions that might exist among bacteria is developed and the consequences of each such model for species delineation, and species identification are discussed. Modes of bacterial evolution, and a theory of bacterial speciation with and without genetic recombination, are examined. The essay concludes with thoughts about prospects for very extensive mapping of bacterial diversity in the service of future efforts to find useful products. In this context, evolutionary biology becomes the handmaiden of important industrial activities. A few examples of past success in commercializing bacterial gene-products from species ofBacillus and a few other bacteria are reviewed.
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  • 51
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    Antonie van Leeuwenhoek 69 (1996), S. 293-303 
    ISSN: 1572-9699
    Keywords: electrophoresis ; bacteria ; evolution ; genome ; microbiology ; restriction-modification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This manuscript examines genome size in bacteria. The opposing capability of bacteria to alter their genome sizes and order of genes within limits yet remain somewhat constant provides a mechanism for diversity and evolution in bacterial populations. Bacteria may have evolved by increasing their genome size and changing gene orders with the assistance of restriction endonucleases cleaving foreign DNA and providing a diverse pool of DNA sequences for recombination. These aspects and selected information on physically mapping bacterial genomes will be discussed.
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  • 52
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    Antonie van Leeuwenhoek 70 (1996), S. 1-10 
    ISSN: 1572-9699
    Keywords: adsorption ; clay ; DNA ; environment ; evolution ; genetic microchip ; interactions ; microorganisms ; nucleases ; soil ; stability ; transformation ; genetic microchip
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This review examines interactions between DNA and soil with an emphasis on the persistence and stability of DNA in soil. The role of DNA in genetic transformation in soil microorganisms will also be discussed. In addition, a postulated mechanism for stabilization and elongation/asserbly of primitive genetic material and the role of soil particles, salt concentrations, temperature cycling and crystal formation is examined.
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  • 53
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    Biodiversity and conservation 5 (1996), S. 963-974 
    ISSN: 1572-9710
    Keywords: parasitism ; evolution ; biodiversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Evolutionary relationships in heterospecific associations (parasitoidism, parasitism, commensalism and mutualism) are analysed through a game theory model defined in terms of fitness of hosts and parasites. In front of the game solutions (i.e. ESS) which present a great diversity of evolutionary patterns, we envisage co-evolution between hosts and parasites through the evolution of its two fundamental parameters (i.e. host's resistance and parasite's virulence). We then discuss the reciprocal influence of hosts and parasites on their respective biodiversity.
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  • 54
    ISSN: 1573-1561
    Keywords: Orthoptera ; Acrididae ; grasshopper ; Melanoplus sanguinipes ; Phoetaliotes nebrascensis ; peritrophic envelope ; peritrophic membrane ; hydrolyzable tannin ; tannic acid ; oxidation ; hydrolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We examined several of the mechanisms that have been reported to enable polyphagous grasshoppers (Orthoptera: Acrididae) to tolerate ingested hydrolyzable tannins: hydrolysis, adsorption on the peritrophic envelope, and peritrophic envelope impermeability. None of these mechanisms explain the tolerance ofMelanoplus sanguinipes to ingested tannic acid. In this species, tannin hydrolysis was 12–47% complete, adsorption accounted for less than 1% of the tannic acid contained in the midgut, and the peritrophic envelope was permeated by several gallotannins. The foregut is the main site for the chemical transformation of tannic acid in this species. InPhoetaliotes nebrascensis, hydrolysis was more extensive (82% complete), but the peritrophic envelope was readily permeated by two gallotannins. Oxidizing redox conditions were found in the guts of both species, and ingested tannins were oxidized inM. sanguinipes. We hypothesize that the tolerance of some polyphagous grasshoppers to ingested hydrolyzable tannins may be the consequence of their ability to tolerate the reactive oxygen species generated by polyphenol oxidation, whereas others may rely on rapid and extensive hydrolysis.
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  • 55
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    Evolutionary ecology 10 (1996), S. 387-404 
    ISSN: 1573-8477
    Keywords: Bumpus ; evolution ; fitness ; house sparrow ; LISREL ; natural selection ; Passer domesticus ; phenotypic selection ; structural equation modelling ; survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We analysed the data of H.C. Bumpus on the survival of house sparrows (Passer domesticus) using structural equation modelling techniques. Using data on seven morphological variables measured by Bumpus, we tested and confirmed a three-factor model that characterized physical attributes for general size, leg size and head size. Although males were physically larger than females, we found no difference between males and females in the physical attributes as measured by the three factors. Survival increased significantly with increasing general size and was unrelated to leg size and head size. Wing length, independent of its relationship to the general size factor, was also significantly related to survival. Higher survival was found among birds with short wings. Males had a higher survival compared to females. Their higher survival was mediated, to a lesser extent indirectly, through greater size and, to a greater extent directly, through effects of unknown origin. We favour the use of structural equation modelling methods in studies of selection because of their ability to test and confirm or disconfirm hypotheses related to selection events.
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  • 56
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    Bulletin of experimental biology and medicine 121 (1996), S. 371-373 
    ISSN: 1573-8221
    Keywords: carbon dioxide ; superoxide anion radical ; tissue cells ; antioxidants ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Carbon dioxide is shown to inhibit the generation of superoxide anion radical in bioptates both directly exposed to CO2 and after preliminary exposure of the whole organism to CO2. A similar effect is noted for gas mixtures similar in composition to arterial and venous blood. The results substantiate the important evolutionary role of CO2 for the maintenance of life on Earth with the appearance of potentially toxic oxygen.
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