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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]
The theory of evolution is widely accepted among the scientific community, serving to link the diverse speciality areas of biology. [19] Evolution provides the field of biology with a solid scientific base. The significance of evolutionary theory is summarised by Theodosius Dobzhansky as "nothing in biology makes sense except in the light of ...
Professor of biology Jerry Coyne sums up biological evolution succinctly: [3]. Life on Earth evolved gradually beginning with one primitive species – perhaps a self-replicating molecule – that lived more than 3.5 billion years ago; it then branched out over time, throwing off many new and diverse species; and the mechanism for most (but not all) of evolutionary change is natural selection.
Evolutionary biology is the subfield of biology that studies the evolutionary processes (natural selection, common descent, speciation) that produced the diversity of life on Earth. It is also defined as the study of the history of life forms on Earth. Evolution holds that all species are related and gradually change over generations. [1]
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 ...
Neutral theory – Theory of evolution by changes at the molecular level; Shifting balance theory – One version of the theory of evolution; Price equation – Description of how a trait or gene changes in frequency over time; Coefficient of relationship – Mathematical guess about inbreeding; Fitness – Expected reproductive success
A number of traits can vary as a result of shortening of the fetal development of a trait or by prolongation of the same. In such a case, a shift in the time a trait is allowed to develop before it is fixed can bring forth an ancestral phenotype. [5] Atavisms are often seen as evidence of evolution. [6]
The Omnigenic Model challenges modern efforts within evolutionary biology to identify traits that are responsible for adaption. [15] Under the Omnigenic Model, trait adaptations that are a result of changes in a single to a few genes may be rare, instead the majority of trait adaptations may be driven by small changes in allele frequency over ...