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Genetic variation can be identified at many levels. Identifying genetic variation is possible from observations of phenotypic variation in either quantitative traits (traits that vary continuously and are coded for by many genes, e.g., leg length in dogs) or discrete traits (traits that fall into discrete categories and are coded for by one or a few genes, e.g., white, pink, or red petal color ...
Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic information of their parents.
Charles Darwin's 1859 book, On the Origin of Species, convinced most biologists that evolution had occurred, but not that natural selection was its primary mechanism. In the 19th and early 20th centuries, variations of Lamarckism (inheritance of acquired characteristics), orthogenesis (progressive evolution), saltationism (evolution by jumps) and mutationism (evolution driven by mutations ...
In population genetics, allele frequencies are used to describe the amount of variation at a particular locus or across multiple loci. When considering the ensemble of allele frequencies for many distinct loci, their distribution is called the allele frequency spectrum .
Genetic variability is either the presence of, or the generation of, genetic differences. It is defined as "the formation of individuals differing in genotype, or the presence of genotypically different individuals, in contrast to environmentally induced differences which, as a rule, cause only temporary, nonheritable changes of the phenotype."
Recent human evolution refers to evolutionary adaptation, sexual and natural selection, and genetic drift within Homo sapiens populations, since their separation and dispersal in the Middle Paleolithic about 50,000 years ago. Contrary to popular belief, not only are humans still evolving, their evolution since the dawn of agriculture is faster ...
The understanding that Mendelian genetics could both preserve discrete variations indefinitely, and support continuous variation for natural selection to work on gradually, meant that most biologists from around 1918 onwards accepted natural selection as the driving force of evolution. [45]
This mutationist view of evolution was later replaced by the reconciliation of Mendelian genetics with natural selection into a gradualistic framework for the neo-Darwinian synthesis. [10] It was the emergence of population thinking in evolution which forced many scientists to adopt gradualism in the early 20th century.