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1.
SUJAL S. PHADKE REBECCA A. ZUFALL 《Biological journal of the Linnean Society. Linnean Society of London》2009,98(1):187-197
Ciliates are a diverse group of microbial eukaryotes that exhibit tremendous variety in several aspects of their mating systems. To understand the evolutionary forces driving mating system diversification in ciliates, we use a comparative approach synthesizing data from many ciliate species in light of recent phylogenetic analyses. Specifically, we investigate the evolution of number of mating types, mode of mating type inheritance, and the molecular determinants of mating types across the taxonomic diversity of ciliates, with an emphasis on three well-studied genera: Tetrahymena , Paramecium , and Euplotes . We find that there have been many transitions in the number of mating types, and that the requirement of nuclear reorganization may be a more important factor than genetic exchange in determining the optimum number of mating types in a species. We also find that the molecular determinants of mating types and mode of inheritance are evolving under different constraints in different lineages of ciliates. Our results emphasize the need for further detailed examination of mating systems in understudied ciliate lineages. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 187–197. 相似文献
2.
N. WAKAYAMA K. ABE 《Biological journal of the Linnean Society. Linnean Society of London》2006,87(3):449-455
The evolutionary history of bioluminescence and iridescence in myodocopid ostracods was estimated by phylogenetic analysis of mitochondrial 16S ribosomal RNA sequences. The inferred phylogeny of the myodocopids suggests that the common ancestor of Myodocopida evaluated in this study exhibits iridescence. This type of light emission was once lost and recaptured independently in the descendant lineages. Bioluminescent species also evolved from non-luminous ancestral species. In the suborder Myodocopina, all the bioluminescent species form a monophyletic group, suggesting that bioluminescence evolved only once. Structural differences between two bioluminescent groups in the order Myodocopida suggests independent origins for bioluminescence. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 449–455. 相似文献
3.
KUIKWON KIM SANLARE THOMAS I. BRIAN HOWARD TIMOTHY A. BELL HEATHER E. DOHERTY FOLAMI IDERAABDULLAH DAVID A. DETWILER FERNANDO PARDO-MANUEL DE VILLENA 《Biological journal of the Linnean Society. Linnean Society of London》2005,84(3):487-492
Meiotic drive is an evolutionary force in which natural selection is uncoupled from organismal fitness. Recently, it has been proposed that meiotic drive and genetic drift represent major forces in the evolution of the mammalian karyotype. Meiotic drive involves two types of genetic elements, Responders and Distorters , the latter being required to induce transmission ratio distortion at the former. We have previously described the Om meiotic drive system in mouse chromosome 11. To investigate the natural history of this drive system we have characterized the alleles present at the distorter in wild-derived inbred strains. Our analysis of transmission of maternal alleles in both classical and wild-derived inbred strains indicated that driving alleles are found at high frequency in natural populations and that the existence of driving alleles predates the split between the Mus spicilegus and M. musculus lineages. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 84 , 487–492. 相似文献
4.
ANGUS DAVISON SATOSHI CHIBA 《Biological journal of the Linnean Society. Linnean Society of London》2006,88(2):269-282
The endemic land snail genus Mandarina of the oceanic Bonin Islands shows exceptionally diverse morphological and ecological traits. Previous studies have already provided evidence that speciation on different islands of the three main archipelagos was such that similar ecotypes evolved independently in different lineages and islands. Here we present data to show that the same species can have different ecotypes. As most of the characters involved are inherited, then variation between ecotypes must represent genetic differences between populations. We then show that the radiation on the Bonin Islands is derived from a single colonization event, and use a mitochondrial phylogeny to provide evidence for a burst of cladogenesis soon after colonization. As divergent selection has previously been implicated in causing differences between Mandarina species, and theory predicts that most of the speciation should have taken place early in their history, then the study adds to the evidence for an adaptive radiation by ecological speciation in Mandarina . However, while the diversity of ecotypes present at each site is dependent on the regime of natural selection and competition, geography still must have an important role. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 269–282. 相似文献
5.
JOEL D. VELASCO 《Biological journal of the Linnean Society. Linnean Society of London》2008,93(4):865-869
Samadi and Barberousse attempt to provide a precise, formal definition of the species category that is faithful to the internodal species concept (Samadi S, Barberousse A. 2006. The tree, the network, and the species. Biological Journal of the Linnean Society 89: 509–521). Here, it is argued that their study is technically flawed. Most of the necessary corrections to their definitions are provided in order to accurately portray the internodal concept. It is then argued that the internodal concept is fundamentally flawed; it does not solve the 'classical problems' that Samadi and Barberousse claim it does. In particular, it does not allow for the possibility of interspecies hybridization. In addition, the proposal is unworkable in practice, and also theoretically problematic because it entails that, in many lineages, speciation events are taking place every few generations. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 865–869. 相似文献
6.
FRANCESCA ZANGARI ROBERTA CIMMARUTA GIUSEPPE NASCETTI 《Biological journal of the Linnean Society. Linnean Society of London》2006,87(4):515-536
Allozymes and sequencing of mitochondrial cytochrome b (cyt b ) and 12S genes were used to reconstruct the genetic structure and phylogenetic relationships of all Discoglossus taxa described so far (except the probably extinct D. nigriventer ). This is the first time that a comprehensive study on the Discoglossus painted frogs has used nuclear and mitochondrial markers, evidencing a discordant pattern between the two datasets. Comparison of these discrepancies suggests a role of stochastic sorting of ancestral polymorphisms, possibly associated with male-biased dispersal and present or past secondary contact. The genetic relationships between taxa with intermediate levels of divergence were well defined by allozyme data, but showed short internodes and low bootstrap values for mitochondrial data, suggesting a rapid radiation of their lineages during the Messinian Lago Mare phase. The results provide information about the taxonomic status of D. galganoi and D. jeanneae , considered as subspecies, and indicate D. pictus as nonmonophyletic, confirming D. scovazzi as a distinct species. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 515–536. 相似文献
7.
The diversity of body sizes observed among species of a clade is a combined result of microevolutionary processes (i.e. natural selection and genetic drift) that cause size changes within phylogenetic lineages, and macroevolutionary processes (i.e. speciation and extinction) that affect net rates of diversification among lineages. Here we assess trends of size diversity and evolution in fishes (non-tetrapod craniates), employing paleontological, macroecological, and phylogenetic information. Fishes are well suited to studies of size diversity and evolution, as they are highly diverse, representing more than 50% of all living vertebrate species, and many fish taxa are well represented in the fossil record from throughout the Phanerozoic. Further, the frequency distributions of sizes among fish lineages resemble those of most other animal taxa, in being right-skewed, even on a log scale. Using an approach that measures rates of size evolution (in darwins) within a formal phylogenetic framework, we interpret the shape of size distributions as a balance between the competing forces of diversification, pushing taxa away from ancestral values, and of conservation, drawing taxa closer to a central tendency. Within this context we show how non-directional mechanisms of evolution (i.e. passive diffusion processes) can produce an hitherto unperceived bias to larger size, when size is measured on the conventional log scale. These results demonstrate how the interpretation of macroecological datasets can be enriched from an historical perspective, and document the ways in which macroevolutionary and microevolutionary processes may be decoupled in the production of size diversity. 相似文献
8.
VLADIMIR VLADIMIROV ZBIGNIEW SZELG 《Botanical journal of the Linnean Society. Linnean Society of London》2006,150(2):261-265
Hieracium petrovae Vladimirov & Szeląg sp. nov. , a new diploid (2 n = 18) species in H. sect. Pannosa Zahn, is described and illustrated from the Rhodope Mountains, South Bulgaria, and compared with related taxa. It grows in relict habitats in crevices of limestone rock together with many Balkan endemics. H. petrovae is morphologically similar to taxa from the H. pannosum , H. pilosissimum and H. heldreichii groups (collective species sensu Zahn) to some of which it is a presumed ancestral species. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 261–265. 相似文献
9.
ISTVÁN KARSAI KÁLMÁN SOMOGYI IAN C.W. HARDY 《Biological journal of the Linnean Society. Linnean Society of London》2006,87(2):285-296
Two important relationships in parasitoid evolutionary ecology are those between adult size and fitness and between host quality and sex ratio. Sexually differential size–fitness relationships underlie predicted sex-ratio relationships. Despite each relationship receiving considerable attention, they have seldom been studied simultaneously or using field data. Here we report the biology of Anoplius viaticus paganu s Dahlbom, a little known parasitoid of spiders, using field and laboratory data. We found that larger foraging females were able to select larger host spiders from the field, thus identifying a relatively novel component of the size–fitness relationship. Larger offspring developed from larger hosts and, in agreement with the prediction of the host quality model of sex allocation, were generally female. Data on the size–fitness relationship for males are lacking and, in common with many prior studies, we could not evaluate sexually differential size–fitness relationships as an explanation for the observed sex-ratio patterns. Nonetheless, A. v. paganu s exhibited one of the strongest relationships between host size and offspring sex ratio yet reported. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 285–296. 相似文献
10.
The genetic architecture of novel trophic specialists: larger effect sizes are associated with exceptional oral jaw diversification in a pupfish adaptive radiation
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The genetic architecture of adaptation is fundamental to understanding the mechanisms and constraints governing diversification. However, most case studies focus on loss of complex traits or parallel speciation in similar environments. It is still unclear how the genetic architecture of these local adaptive processes compares to the architecture of evolutionary transitions contributing to morphological and ecological novelty. Here, we identify quantitative trait loci (QTL) between two trophic specialists in an excellent case study for examining the origins of ecological novelty: a sympatric radiation of pupfishes endemic to San Salvador Island, Bahamas, containing a large‐jawed scale‐eater and a short‐jawed molluscivore with a skeletal nasal protrusion. These specialized niches and trophic traits are unique among over 2000 related species. Measurements of the fitness landscape on San Salvador demonstrate multiple fitness peaks and a larger fitness valley isolating the scale‐eater from the putative ancestral intermediate phenotype of the generalist, suggesting that more large‐effect QTL should contribute to its unique phenotype. We evaluated this prediction using an F2 intercross between these specialists. We present the first linkage map for pupfishes and detect significant QTL for sex and eight skeletal traits. Large‐effect QTL contributed more to enlarged scale‐eater jaws than the molluscivore nasal protrusion, consistent with predictions from the adaptive landscape. The microevolutionary genetic architecture of large‐effect QTL for oral jaws parallels the exceptional diversification rates of oral jaws within the San Salvador radiation observed over macroevolutionary timescales and may have facilitated exceptional trophic novelty in this system. 相似文献
11.
TODD GRANTHAM 《Palaeontology》2007,50(1):75-85
Abstract: Whether macrovolution is reducible to microevolution is one of the persistent debates in evolutionary biology. Although the concept of emergence is important to answering this question, it has not been extensively discussed within palaeobiology. A taxonomy of emergence concepts is presented to clarify the ways in which emergence relates to this debate. Weak emergence is a particularly helpful way to understand the hierarchical nature of biology: it captures the ways in which higher-level traits depend on lower-level processes, while recognizing that emergent traits can nonetheless provide the basis for autonomous higher-level theories. A brief review of the biological literature suggests that geographical range size is weakly emergent. While some concepts of emergence do not block the attempt to reduce macroevolution (i.e. the attempt to explain all macroevolutionary phenomena in terms of microevolutionary processes), weak emergence does. Thus, if geographical range is weakly emergent, it provides a basis for arguing that macroevolutionary phenomena cannot be fully explained by microevolutionary processes. 相似文献
12.
TATSUYA TOGASHI PAUL ALAN COX fls 《Botanical journal of the Linnean Society. Linnean Society of London》2004,144(3):321-327
The evolution of anisogamy in marine algae was studied through numerical simulations of gamete mating behaviour in three dimensions, using observed traits of marine green algae as input parameters. The importance of phototaxis became apparent from the numerical experiments: all gametes with phototactic systems are favoured over those without, but this advantage is reduced with increasing tank depth or shorter search times. Phototactic gametes were advantaged over non-phototactic gametes if the water was shallower than about 30–40 mm when the time available for gamete encounter was 1000 time steps (5.55 min). If gametes of both sexes are positively phototactic, slightly anisogamous species are at a disadvantage to isogamous species, which invalidates the sperm-limitation theory as a driver for the evolution of slight anisogamy. Conflicting selection forces of search efficiency and zygote fitness may be needed. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 321–327. 相似文献
13.
MATHIEU DENOËL HOWARD H. WHITEMAN SCOTT A. WISSINGER 《Biological journal of the Linnean Society. Linnean Society of London》2006,89(2):373-382
Evolutionary theory predicts that alternative trophic morphologies are adaptive because they allow a broad use of resources in heterogeneous environments. The development of a cannibal morphology is expected to result in cannibalism and high individual fitness, but conflicting results show that the situation is more complex. The goal of the present study was to increase our understanding of the ultimate benefits of a cannibalistic polyphenism by determining temporal changes in the feeding habits and biomass intake in a population of tiger salamanders ( Ambystoma tigrinum nebulosum ). Cannibals in this species develop a larger head than typicals and have prominent teeth, both useful for consuming large prey. Although cannibalism was only detected in cannibal morphs, large temporal variation in resource partitioning was found between morphs. The two morphs always differed in their foraging habits, but cannibalism mainly occurred immediately after the ontogenetic divergence between morphs. Cannibals shifted their foraging later to a more planktivorous diet (i.e. the primarily prey of the typical morph). Cannibals also obtained more prey biomass than typicals. These results indicate that the cannibalistic morph is advantageous over the typical development, but that these advantages vary ontogenetically. Although the results obtained are consistent with models predicting the maintenance of cannibalism polyphenism in natural populations, they show that the foraging tactics utilized by cannibal morphs, and the fitness consequences accrued by such tactics, are likely to be more complex and dynamic than previous studies have suggested. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 373–382. 相似文献
14.
The dynamic clonal genome and its adaptive potential 总被引:4,自引:0,他引:4
GUGS LUSHAI HUGH D. LOXDALE JOHN A. ALLEN 《Biological journal of the Linnean Society. Linnean Society of London》2003,79(1):193-208
Populations of clonal organisms are often represented as being evolutionary inert with persistent genetic fidelity. The advent of molecular methods and the corresponding increased genetic resolution of clonal populations forces a reconsideration of this viewpoint. We review molecular data from viruses, prokaryotes and eukaryotes to support the argument that clones possess a highly dynamic and adaptive genome. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 79 , 193–208. 相似文献
15.
High photobiont diversity associated with the euryoecious lichen-forming ascomycete Lecanora rupicola (Lecanoraceae, Ascomycota) 总被引:1,自引:0,他引:1
JULIANE BLAHA ELISABETH BALOCH MARTIN GRUBE 《Biological journal of the Linnean Society. Linnean Society of London》2006,88(2):283-293
The diversity and phylogenetic position of photobionts in the widespread saxicolous, crustose lichen-forming ascomycete Lecanora rupicola s.l. is presented. The algal partners of this lichen species complex belong to diverse and unrelated lineages in the genus Trebouxia . Specimens were sampled from different habitats and geographical origins. Either whole thallus DNA extractions or minute fragments of the algal layer of the lichen thallus were subjected to polymerase chain reaction, using primers that specifically amplify internal transcribed spacer rDNA of the photobionts. No correlations between different chemical races of L. rupicola with particular lineages of Trebouxia spp. were found. Irrespective of the different algal partners, all lichen thalli abundantly developed ascomata. L. rupicola apparently maintains full fecundity with a low degree of selectivity for photobionts, which promotes the occurrence of this lichen-forming species in ample ecological situations. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 283–293. 相似文献
16.
NICOLAS DEVOS OLIVIER RASPÉ ANNE–LAURE JACQUEMART DANIEL TYTECA 《Botanical journal of the Linnean Society. Linnean Society of London》2006,152(3):261-269
Previous phylogenetic analyses of Orchidaceae subtribe Orchidinae resulted in the proposal to classify Coeloglossum viride (L.) Hartman within the genus Dactylorhiza in order to maintain its monophyly. In this paper, we report some results that contradict previous studies regarding the monophyly of the traditional Dactylorhiza and its phylogenetic relationship with Coeloglossum. Our results, which combine sequences of the internal and external transcribed spacers of the nuclear ribosomal DNA, support the monophyly of Dactylorhiza , with Coeloglossum being a sister clade. The position of C. viride in the phylogenetic tree, and the considerable morphological differences with respect to Dactylorhiza , incline us to retain both lineages as distinct genera. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 261–269. 相似文献
17.
MUIR D. EATON JORGE SOBERÓN A. TOWNSEND PETERSON 《Biological journal of the Linnean Society. Linnean Society of London》2008,94(4):869-878
Analysis of ecological characters on phylogenetic frameworks has only recently appeared in the literature, with several studies addressing patterns of niche evolution, generally over relatively recent time frames. In the present study, we examined patterns of niche evolution for a broad radiation of American blackbird species (Family Icteridae), exploring more deeply into phylogenetic history. Within each of three major blackbird lineages, overlap of ecological niches in principal components analysis transformed environmental space varied from high to none. Comparative phylogenetic analyses of ecological niche characteristics showed a general pattern of niche conservatism over evolutionary time, with differing degrees of innovation among lineages. Although blackbird niches were evolutionarily plastic over differing periods of time, they diverged within a limited set of ecological possibilities, resulting in examples of niche convergence among extant blackbird species. Hence, an understanding of the patterns of ecological niche evolution on broad phylogenetic scales sets the stage for framing questions of evolutionary causation, historical biogeography, and ancestral ecological characteristics more appropriately. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 869–878. 相似文献
18.
VICTORIA SOSA HELGA OCHOTERENA MANUEL ESCAMILLA 《Botanical journal of the Linnean Society. Linnean Society of London》2006,152(1):1-13
Cerdia is a poorly understood genus of minute cushiony plants endemic to Mexico that is traditionally placed in subfamily Paronychioideae, tribe Polycarpeae (Caryophyllaceae). Morphological observations and phylogenetic analysis of ITS DNA sequences were carried out to determine the number of species, heretofore controversial, that constitute the genus as well as its position within Caryophyllaceae. Samples of Cerdia were collected through its entire range of distribution and together with previous specimens were used in morphological analyses. Nineteen terminal taxa were considered in a phylogenetic analysis with representatives of the different lineages in Caryophyllaceae. Results indicated that Cerdia is a monotypic genus, including only one variable species, C . virescens , but its phylogenetic affinities remain doubtful. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 1–13. 相似文献
19.
GAURI R. PRADHAN CAREL P. VAN SCHAIK 《Biological journal of the Linnean Society. Linnean Society of London》2009,96(2):372-382
Vertebrates show two major classes of sexually dimorphic traits: weaponry and ornaments. However, Darwin could not explain why their expression varies so much across lineages. We argue that coercion-avoidance can explain both the existence and taxonomic distribution of ornaments. Females maximize their fitness when they can freely choose their mates, but males are expected to use sexually dimorphic weaponry not only to displace other males, but also to overcome female preferences and thus acquire matings by force whenever they can. Females should therefore avoid coercive males and avoid using weaponry as a criterion for male quality wherever possible, and rely on male viability indicators that cannot be used to coerce females (i.e. ornaments). Ornaments predominate in birds and weaponry in mammals because female choice is less costly in birds, due to higher intrinsic female behavioural freedom and lower male monopolization potential. We also predict that specialized coercive organs occur where females have low behavioural freedom but males benefit little from weaponry in male–male contests. A review of the empirical evidence supports the basic predictions of this coercion-avoidance hypothesis. We also present a simple mathematical model that confirms the logic of this hypothesis. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 372–382. 相似文献
20.
KATJA PUSCH BERNHARD SEIFERT SUSANNE FOITZIK JÜRGEN HEINZE 《Biological journal of the Linnean Society. Linnean Society of London》2006,88(2):223-234
The two sibling ant species Temnothorax nylanderi and Temnothorax crassispinus are widely distributed throughout deciduous forests in Europe. Their resemblance in morphology and similar ecological requirements suggest that they evolved from the same ancestral species in different glacial refugia and re-immigrated into Central Europe after the last ice age. Here, we show that the two species are parapatrically distributed in south-eastern Germany and hybridize along a narrow contact zone close to the continental divide. Phylogeographical data based on the mitochondrial genes cytochrome oxidase subunit I and cytochrome b suggest that the dominant haplotypes for T. nylanderi and T. crassispinus might have diverged already 1.5–2 Mya. Intraspecific variability is extremely low in both species, which might be explained by severe bottlenecks during rapid postglacial expansion into Central Europe. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 223–234. 相似文献