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The term natural selection is most often defined to operate on heritable traits, because these directly participate in evolution. However, natural selection is "blind" in the sense that changes in phenotype can give a reproductive advantage regardless of whether or not the trait is heritable.
Evolution is the change in the heritable characteristics of biological populations over successive generations. [1] [2] It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. [3]
Animal coloration, readily observable, soon provided strong and independent lines of evidence, from camouflage, mimicry and aposematism, that natural selection was indeed at work. [ 6 ] [ 7 ] [ 8 ] The historian of science Peter J. Bowler wrote that Darwin's theory "was also extended to the broader topics of protective resemblances and mimicry ...
In both natural and artificial selection the variations are a result of random mutations, and the underlying genetic processes are essentially the same. [66] Darwin carefully observed the outcomes of artificial selection in animals and plants to form many of his arguments in support of natural selection. [67]
With only a handful of species surviving today, the Nautiloids flourished during the early Paleozoic era, from the Late Cambrian, where they constituted the main predatory animals. [71] Haikouichthys , a jawless fish , is popularized as one of the earliest fishes and probably a basal chordate or a basal craniate . [ 72 ]
Natural selection is inherently involved in the process of speciation, whereby, "under ecological speciation, populations in different environments, or populations exploiting different resources, experience contrasting natural selection pressures on the traits that directly or indirectly bring about the evolution of reproductive isolation". [54]
On the Origin of Species (or, more completely, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life) [3] is a work of scientific literature by Charles Darwin that is considered to be the foundation of evolutionary biology. It was published on 24 November 1859. [4]
This process of speciation influenced by natural selection is reinforcement, and can happen under any mode of speciation [3]: 355 (e.g. geographic modes of speciation or ecological speciation [21]). It necessitates two forces of evolution that act on mate choice: natural selection and gene flow. [22]