Search results
Results from the WOW.Com Content Network
Natural selection is the ... Different types of selection act at ... The peacock's elaborate plumage is mentioned by Darwin as an example of sexual selection, ...
Natural selection within a population for a trait that can vary across a range of values, such as height, can be categorised into three different types. The first is directional selection, which is a shift in the average value of a trait over time—for example, organisms slowly getting taller. [80]
Natural selection, with its emphasis on death and competition, did not appeal to some naturalists because they felt it immoral, leaving little room for teleology or the concept of progress (orthogenesis) in the development of life. Some who came to accept evolution, but disliked natural selection, raised religious objections.
Yet while people from the developed world today are living longer and healthier lives, many are choosing to have just a few or no children at all, meaning evolutionary forces continue to act on the human gene pool, just in a different way. [95] Natural selection affects only 8% of the human genome, meaning mutations in the remaining parts of ...
Sexual selection is quite different in non-human animals than humans as they feel more of the evolutionary pressures to reproduce and can easily reject a mate. [2] The role of sexual selection in human evolution has not been firmly established although neoteny has been cited as being caused by human sexual selection. [3]
Disruptive selection is a specific type of natural selection that actively selects against the intermediate in a population, favoring both extremes of the spectrum. Disruptive selection is inferred to oftentimes lead to sympatric speciation through a phyletic gradualism mode of evolution. Disruptive selection can be caused or influenced by ...
Stabilizing selection (not to be confused with negative or purifying selection [1] [2]) is a type of natural selection in which the population mean stabilizes on a particular non-extreme trait value. This is thought to be the most common mechanism of action for natural selection because most traits do not appear to change drastically over time ...
Edward Bagnall Poulton's 1890 book, The Colours of Animals, renamed Wallace's concept of warning colours "aposematic" coloration, as well as supporting Darwin's then unpopular theories of natural selection and sexual selection. [18] Poulton's explanations of coloration are emphatically Darwinian. For example, on aposematic coloration he wrote that