Home About us Contact
|
Home About us Contact | ||
|
|
||
Phylogenetic Niche Conservatism (phylogenetic + niche_conservatism)
Selected AbstractsPhylogenetic niche conservatism, phylogenetic signal and the relationship between phylogenetic relatedness and ecological similarity among speciesECOLOGY LETTERS, Issue 10 2008Jonathan B. Losos Abstract Ecologists are increasingly adopting an evolutionary perspective, and in recent years, the idea that closely related species are ecologically similar has become widespread. In this regard, phylogenetic signal must be distinguished from phylogenetic niche conservatism. Phylogenetic niche conservatism results when closely related species are more ecologically similar that would be expected based on their phylogenetic relationships; its occurrence suggests that some process is constraining divergence among closely related species. In contrast, phylogenetic signal refers to the situation in which ecological similarity between species is related to phylogenetic relatedness; this is the expected outcome of Brownian motion divergence and thus is necessary, but not sufficient, evidence for the existence of phylogenetic niche conservatism. Although many workers consider phylogenetic niche conservatism to be common, a review of case studies indicates that ecological and phylogenetic similarities often are not related. Consequently, ecologists should not assume that phylogenetic niche conservatism exists, but rather should empirically examine the extent to which it occurs. [source] EVOLUTIONARY CONSTRAINT AND ECOLOGICAL CONSEQUENCESEVOLUTION, Issue 7 2010Douglas J. Futuyma One of the most important shifts in evolutionary biology in the past 50 years is an increased recognition of sluggish evolution and failures to adapt, which seem paradoxical in view of abundant genetic variation and many instances of rapid local adaptation. I review hypotheses of evolutionary constraint (or restraint), and suggest that although constraints on individual characters or character complexes may often reside in the structure or paucity of genetic variation, organism-wide stasis, as described by paleontologists, might better be explained by a hypothesis of ephemeral divergence, according to which the spatial or temporal divergence of populations is often short-lived because of interbreeding with nondivergent populations. Among the many consequences of acknowledging evolutionary constraints, community ecology is being transformed as it takes into account phylogenetic niche conservatism and the strong imprint of deep history. [source] Can the tropical conservatism hypothesis explain temperate species richness patterns?GLOBAL ECOLOGY, Issue 4 2009An inverse latitudinal biodiversity gradient in the New World snake tribe Lampropeltini ABSTRACT Aim, A latitudinal gradient in species richness, defined as a decrease in biodiversity away from the equator, is one of the oldest known patterns in ecology and evolutionary biology. However, there are also many known cases of increasing poleward diversity, forming inverse latitudinal biodiversity gradients. As only three processes (speciation, extinction and dispersal) can directly affect species richness in areas, similar factors may be responsible for both classical (high tropical diversity) and inverse (high temperate diversity) gradients. Thus, a modified explanation for differential species richness which accounts for both patterns would be preferable to one which only explains high tropical biodiversity. Location, The New World. Methods, We test several proposed ecological, temporal, evolutionary and spatial explanations for latitudinal diversity gradients in the New World snake tribe Lampropeltini, which exhibits its highest biodiversity in temperate regions. Results, We find that an extratropical peak in species richness is not explained by latitudinal variation in diversification rate, the mid-domain effect, or Rapoport's rule. Rather, earlier colonization and longer duration in the temperate zones allowing more time for speciation to increase biodiversity, phylogenetic niche conservatism limiting tropical dispersal and the expansion of the temperate zones in the Tertiary better explain inverse diversity gradients in this group. Main conclusions, Our conclusions are the inverse of the predictions made by the tropical conservatism hypothesis to explain higher biodiversity near the equator. Therefore, we suggest that the processes invoked are not intrinsic to the tropics but are dependent on historical biogeography to determine the distribution of species richness, which we refer to as the ,biogeographical conservatism hypothesis'. [source] Parallel evolution of larval morphology and habitat in the snail-killing fly genus TetanoceraJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2006E. G. CHAPMAN Abstract In this study, we sequenced one nuclear and three mitochondrial DNA loci to construct a robust estimate of phylogeny for all available species of Tetanocera. Character optimizations suggested that aquatic habitat was the ancestral condition for Tetanocera larvae, and that there were at least three parallel transitions to terrestrial habitat, with one reversal. Maximum likelihood analyses of character state transformations showed significant correlations between habitat transitions and changes in four larval morphological characteristics (cuticular pigmentation and three characters associated with the posterior spiracular disc). We provide evidence that phylogenetic niche conservatism has been responsible for the maintenance of aquatic-associated larval morphological character states, and that concerted convergence and/or gene linkage was responsible for parallel morphological changes that were derived in conjunction with habitat transitions. These habitat,morphology associations were consistent with the action of natural selection in facilitating the morphological changes that occurred during parallel aquatic to terrestrial habitat transitions in Tetanocera. [source] | ||||||||||