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Microevolution is the change in allele frequencies that occurs over time within a population. [1] ... Factors which affect reproductive success are also important, ...
He helped to bridge the divide between the foundations of microevolution developed by the population geneticists and the patterns of macroevolution observed by field biologists, with his 1937 book Genetics and the Origin of Species. Dobzhansky examined the genetic diversity of wild populations and showed that, contrary to the assumptions of the ...
The Russian evolutionary biologist Ivan Schmalhausen founded the theory of stabilizing selection, publishing a paper in Russian titled "Stabilizing selection and its place among factors of evolution" in 1941 and a monograph "Factors of Evolution: The Theory of Stabilizing Selection" in 1945. [5] [6]
In this sense, microevolution and macroevolution might involve selection at different levels—with microevolution acting on genes and organisms, versus macroevolutionary processes such as species selection acting on entire species and affecting their rates of speciation and extinction. [138] [139] [140]
There are a number of factors that affect the rate of gene flow between different populations. Gene flow is expected to be lower in species that have low dispersal or mobility, that occur in fragmented habitats, where there is long distances between populations, and when there are small population sizes.
Evolutionary pressure, selective pressure or selection pressure is exerted by factors that reduce or increase reproductive success in a portion of a population, driving natural selection. [1] It is a quantitative description of the amount of change occurring in processes investigated by evolutionary biology , but the formal concept is often ...
Cave paintings (such as this one from France) represent a benchmark in the evolutionary history of human cognition. Victorian naturalist Charles Darwin was the first to propose the out-of-Africa hypothesis for the peopling of the world, [40] but the story of prehistoric human migration is now understood to be much more complex thanks to twenty-first-century advances in genomic sequencing.
The effective population (N e) takes into account factors such as the level of inbreeding, the stage of the lifecycle in which the population is the smallest, and the fact that some neutral genes are genetically linked to others that are under selection. [14] The effective population size may not be the same for every gene in the same ...