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A prerequisite for natural selection to result in adaptive evolution, novel traits and speciation is the presence of heritable genetic variation that results in fitness differences. Genetic variation is the result of mutations, genetic recombinations and alterations in the karyotype (the number, shape, size and internal arrangement of the ...
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]
if its properties show heritable genetic variation, and; if natural selection can thus change these properties. According to the second definition, a biological system is evolvable: if it can acquire novel functions through genetic change, functions that help the organism survive and reproduce.
It defines evolution as the change in allelic frequencies within a population caused by genetic drift, gene flow between sub populations, and natural selection. Natural selection is emphasised as the most important mechanism of evolution; large changes are the result of the gradual accumulation of small changes over long periods of time. [39] [40]
The gene-centered view of evolution is a synthesis of the theory of evolution by natural selection, the particulate inheritance theory, and the rejection of transmission of acquired characters. [ 6 ] [ 7 ] It states that those alleles whose phenotypic effects successfully promote their own propagation will be favorably selected relative to ...
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]
The rationale behind the role of the organism, or more specifically the embryo, as a causal force in evolution and for the existence of bias is as follows: The traditional, neo-Darwinian, approach to explain the process behind evolutionary change is natural selection acting upon heritable variation caused by genetic mutations. [9] However ...
However, it is possible that cultural evolution could actually increase genetic adaptation. Cultural evolution has vastly increased communication and contact between different populations, and this provides much greater opportunities for genetic admixture between the different populations (Hawks et al. 2007).