Search results
Results from the WOW.Com Content Network
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 ...
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.
The American naturalist J. T. Gulick (1832–1923) was the first to use the term "divergent evolution", with its use becoming widespread in modern evolutionary literature. [2] Examples of divergence in nature are the adaptive radiation of the finches of the Galápagos, changes in mobbing behavior of the kittiwake, and the evolution of the ...
Examples of tradeoffs can also be found in studies involving human subjects. A tradeoff can be seen between growth and immune function in human populations in which energy is a limiting factor. A study conducted on rural Bolivia found that children experiencing an elevated immune response had smaller gains in height than those with a normal ...
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 ...
The timeline of human evolution outlines the major events in the evolutionary lineage of the modern human species, Homo sapiens, throughout the history of life, beginning some 4 billion years ago down to recent evolution within H. sapiens during and since the Last Glacial Period.
Skin pigmentation is an evolutionary adaptation to the various UV radiation levels around the world. There are health implications of light-skinned people living in environments of high UV radiation. Various cultural practices increase problems related to health conditions of light skin, for example sunbathing among the light-skinned.
An evolutionary tree (of Amniota, for example, the last common ancestor of mammals and reptiles, and all its descendants) illustrates the initial conditions causing evolutionary patterns of similarity (e.g., all Amniotes produce an egg that possesses the amnios) and the patterns of divergence amongst lineages (e.g., mammals and reptiles ...