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21.
Phylogenetic relationships among gekkotan lizards inferred from C-mos nuclear DNA sequences and a new classification of the Gekkota 总被引:3,自引:0,他引:3
DEMIN HAN KAIYA ZHOU AARON M. BAUER 《Biological journal of the Linnean Society. Linnean Society of London》2004,83(3):353-368
A phylogeny of gekkotan lizards was derived from C- mos nuclear DNA sequence data. Forty-one currently recognized genera, representing all major gekkotan lineages, were included in the study. A total of 378 bp of partial C- mos gene sequences was obtained and aligned. Maximum parsimony (MP) and maximum likelihood (ML) trees were generated based on unweighted analysis using P AUP *; similar tree topologies were recovered by both methods. The Eublepharidae were monophyletic and its relationship to other major clades was poorly resolved. The Pygopodidae of Kluge (1987) was monophyletic, but relationships within this group differed from those retrieved by previous analyses. The Diplodactylini + padded carphodactylines were the sister group of pygopods + padless carphodactylines. The Gekkonidae were monophyletic, but we found no evidence in support of the Teratoscincinae, as Teratoscincus was embedded well within the gekkonids. Both MP and ML analyses supported the basal position of Sphaerodactylus within the gekkonids, in contrast to morphologically based hypotheses. We propose a new higher order classification of the Gekkota that reflect these results. Five gekkotan families: Eublepharidae, Gekkonidae, Pygopodidae, Diplodactylidae, and Carphodactylidae are recognized. The higher order status of the sphaerodactyls will require more intensive sampling of this group. Our results support the hypothesis that the early cladogenesis of the Gekkota was associated with the split of Eastern Gondwanaland from Western Gondwanaland. Divergences among living genera in the Eublepharidae and the Eastern Gondwanan lineages (Diplodactylidae, Pygopodidae and Carphodactylidae) may be older than those in the Gekkonidae. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 83 , 353–368. 相似文献
22.
The apparent photosynthetic affinity-for inorganic carbon inSpirulina is severely reduced by exposing the cells to CO2-depletedconditions in the light. The extent of reduction depends onthe length of exposure, the light intensity, and the O2 concentration.The photosynthetic dependence on inorganic carbon (CInorg) concentration,however, is similar at 3% O2 and at 25% O2 but in the presenceof catalase. The amount of O2 released following the additionof catalase to the cell suspension also depends on the O2 andCO2 concentrations. The addition of H2O2 either to the cellsuspension or by a treatment with methyl viologen caused a severeinhibition of the capability of the cells to accumulate inorganiccarbon internally. It is suggested that the reduction of thephotosynthetic apparent affinity to CInorg upon subjecting thecells to photoinhibitory conditions is caused by an alterationof their ability to accumulate CInorg due to the accumulationof H2O2. 相似文献
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24.
AARON P. DAVIS JOHN R. BARNETT 《Botanical journal of the Linnean Society. Linnean Society of London》1997,123(4):333-352
The leaf anatomy of the genus Galanthus is described from transverse sections of the leaf and epidermal preparations, with the objective of identifying systematic information. Eight characters are identified as having the potential to provide data for grouping species and subspecies; six of these characters are reported here for the first time. Some of these characters, alone or in combination with other anatomical data, are useful for looking at the relationships between taxbnomically difficult species. Our results are compared with the classifications of Artjushenko, which are based on anatomical and morphological data. 相似文献
25.
KATIA C. M. PELLEGRINO MIGUEL T. RODRIGUES AARON N. WAITE MARIANA MORANDO YATIYO Y. YASSUDA JACK W. SITES JR 《Biological journal of the Linnean Society. Linnean Society of London》2005,85(1):13-26
Phylogenetic analyses based on mtDNA cytochrome b were performed in 42 lizards of the Gymnodactylus darwinii complex from three regions within Brazil's Atlantic Forest. Mainland regions and continental shelf islands in the south-eastern range and mainland areas from the north-east were sampled. The criteria of maximum parsimony (MP), maximum likelihood (ML) and Bayesian methods were explored, with the robustness for nodes assessed by bootstrapping (MP and ML) and posterior probabilities (Bayesian searches). By all methods, three distinctive phylogroups were recovered: a south-eastern clade (SE) and two clades from northern regions (NE1 and NE2 ). The pattern of genetic structure of the major clades coincided with the presence of river systems in the Atlantic Forest, and based on corrected genetic distances between those clades, divergence times were tentatively estimated using mtDNA rates calibrated for squamate reptiles. The putative role of Atlantic Forest rivers in generating differentiation is discussed. We present a hypothesis of species limits for G. darwinii , based on concordant lines of evidence including cytogenetic and mtDNA analyses. Two chromosome races (cytotype A, 2n = 38; and cytotype B, 2n = 40) had distributions concordant with clades SE and NE1 + NE2 , respectively. These races are interpreted to be full species on the basis of a number of empirical criteria. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 13–26. 相似文献
26.
Survivorship and Spatial Development of Spartina alterniflora Loisel. (Gramineae) Seedlings in a New England Salt Marsh 总被引:5,自引:0,他引:5
Patterns of survival and spatial arrangement of tillers of Spartinaalterniflora were examined in natural and in artificially producedbare areas, and in pure stands of adult S. alterniflora in aNew England salt marsh. Seedling growth and survival were highin naturally occurring bare patches and in artificial patches,whether created by continual clipping of adult plants to groundlevel throughout the growing season or by providing bare substrateafter removal of adult plants. Seedling growth and survivorshipincreased with increasing size of bare area. S. alternifloraseedlings were also common in areas dominated by adult plants,but no seedlings survived a whole first growing season underthe mature canopy, probably because of competition from adultplants. In large bare areas, S. alterniflora seedlings grew non-directionally,reaching heights of 0.5 m, and producing as many as 36 tillersin one growing season. Examination of leaf area ratios suggestedthat the production of tillers increased photosynthetic capacityin seedlings with several tillers in contrast to seedlings withouttillers. Thus, seedlings can apparently tiller and colonizefree space radially without a loss of photosynthetic capacity. These results suggest that while seedling success is generallylimited by adult plants in monocultures of S. alterniflora,in disturbed spaces seedling success is high and results ina rapid non-directional proliferation of sexually generatedclones that ultimately preclude the successful invasion of futureseedlings. Clones, directional growth, leaf area ratio, salt marsh cordgrass, seedling survivorship, Spartina alterniflora Loisel 相似文献
27.
Sex ratio and gender stability in the dioecious plants of Israel 总被引:4,自引:0,他引:4
AARON ROTTENBERG 《Botanical journal of the Linnean Society. Linnean Society of London》1998,128(2):137-148
The hypothesis that in dioecious plants genders are usually stable and that the sex ratio is 1:l was tested in the dioecious species of Israel. The flora of Israel comprises some 2500 wild species, among which 43 are dioecious, one gynodioecious and one androdioecious. Forty-one out of these 45 species were examined during 1995-97. These species were examined in 120 populations comprising 7019 individuals, at 81 different localities. The majority of the species (33/41) manifested the expected 1:1 sex ratio. Of the eight species deviating from this ratio, a significant bias was repeatedly scored in five of them. Three other species of the willow family manifested sometimes strongly biased sex ratios or even monomorphic (unisexual) stands, apparently as a result of extensive vegetative cloning. The stability of the male and female morphs was also examined in the 41 species. Only eight individuals (from seven species) out of the 7019 individuals surveyed (0.1%) were found to be bisexual. In addition, in 27 populations belonging to 17 species, 909 males were tagged and revisited in fruiting time, and only three of them (0.3%) were found to set fruits. In addition not a single case of gender reversal between seasons was found. The field survey suggests that in dioecious plants sex determination and expression are usually effectively maintained. The very slight deviations from the 1:1 sex ratio and from the distinct male and female morphs suggest that sexual dimorphism in dioecious plants is usually stabile. 相似文献
28.
AARON B. LERNER 《Pigment cell & melanoma research》1999,12(2):131-144
29.
JONG SOO PARK MARTIN KOLISKO AARON A. HEISS ALASTAIR G.B. SIMPSON 《The Journal of eukaryotic microbiology》2009,56(4):373-384
ABSTRACT. We describe Hicanonectes teleskopos n. g., n. sp., a heterotrophic flagellate isolated from low-oxygen marine sediment. Hicanonectes teleskopos has a ventral groove and two unequal flagella, and rapidly rotates during swimming. At the ultrastructural level H. teleskopos is a "typical excavate": it displays flagellar vanes, a split right microtubular root, "I,""B," and "C" fibres, a singlet microtubular root, and a possible composite fibre. Small subunit rRNA (SSU rRNA) gene phylogenies and an "arched" B fibre demonstrate that H. teleskopos belongs to Fornicata (i.e. diplomonads, retortamonads, and relatives). It forms a clade with the deep-branching fornicate Carpediemonas , with moderate-to-strong bootstrap support, although their SSU rRNA gene sequences are quite dissimilar. Hicanonectes differs from Carpediemonas in cell shape, swimming behaviour, number of basal bodies (i.e. 4 vs. 3), number of flagellar vanes (i.e. 2 vs. 3), anterior root organization, and by having a cytopharynx. Like Carpediemonas and Dysnectes, Hicanonectes has conspicuous mitochondrion-like organelles that lack cristae and superficially resemble the hydrogenosomes of parabasalids, rather than the mitosomes of their closer relatives the diplomonads (e.g. Giardia ). 相似文献
30.
AARON M. LAMPMAN 《American anthropologist》2006,108(3):556-557
The Logic of Environmentalism: Anthropology, Ecology and Postcoloniality. Vassos Argyrou. New York: Berghahn Books, 2005. 195 pp. 相似文献