Search results
Results from the WOW.Com Content Network
t. e. In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, alters biotic interactions or opens new environmental niches. [1][2] Starting with a single ancestor, this ...
Divergent evolution or divergent selection is the accumulation of differences between closely related populations within a species, sometimes leading to speciation. Divergent evolution is typically exhibited when two populations become separated by a geographic barrier (such as in allopatric or peripatric speciation) and experience different ...
A human molar with four cusps. A key innovation may allow a species to invade a new region or niche and thus be freed from competition, allowing subsequent speciation and radiation. A classic example of this is the fourth cusp of mammalian molars, the hypocone, which allowed early mammalian ancestors to effectively digest their generalised diet ...
Adaptation is the evolutionary process whereby an organism becomes better able to live in its habitat or habitats. [25][26][27] 2. Adaptedness is the state of being adapted: the degree to which an organism is able to live and reproduce in a given set of habitats. [28]
An evolutionary radiation is an increase in taxonomic diversity that is caused by elevated rates of speciation, [1] that may or may not be associated with an increase in morphological disparity. [2] A significantly large and diverse radiation within a relatively short geologic time scale (e.g. a period or epoch) is often referred to as an ...
The rate of adaptive evolution in the human genome has often been assumed to be constant over time. For example, the 35% estimate for α calculated by Fay et al. (2001) led them to conclude that there was one adaptive substitution in the human lineage every 200 years since human divergence from old-world monkeys. However, even if the original ...
Anole lizards, with populations on isolated islands, are one of the best examples of both adaptive radiation and convergent evolution. Anoles on a given island evolve into multiple body types and ecological preferences, and the same set of body types appears in unrelated species across distant islands. [91]
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy.