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Adaptation affects all aspects of the life of an organism. [24] The following definitions are given by the evolutionary biologist Theodosius Dobzhansky: 1. Adaptation is the evolutionary process whereby an organism becomes better able to live in its habitat or habitats. [25] [26] [27] 2.
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]
Genetic variation is the difference in DNA among individuals [1] or the differences between populations among the same species. [2] The multiple sources of genetic variation include mutation and genetic recombination. [3] Mutations are the ultimate sources of genetic variation, but other mechanisms, such as genetic drift, contribute to it, as ...
Population genetics is a subfield of genetics that deals with genetic differences within and among populations, and is a part of evolutionary biology.Studies in this branch of biology examine such phenomena as adaptation, speciation, and population structure.
Variation in the populations gene pool allows natural selection to act upon traits that allow the population to adapt to changing environments. Selection for or against a trait can occur with changing environment – resulting in an increase in genetic diversity (if a new mutation is selected for and maintained) or a decrease in genetic ...
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 ...
A graphical representation of the typical human karyotype The human mitochondrial DNA. Human genetic variation is the genetic differences in and among populations.There may be multiple variants of any given gene in the human population (), a situation called polymorphism.
Heritable differences is a key feature in ecotypic variation. [38] Ecotypic variation is as a result of particular environmental trends. [ 36 ] Individuals, which are able to survive and reproduce successfully pass on their genes to the next generation and establish a population best adapted to the local environment.