The phrase horizontal evolution is used in evolutionary biology to refer to:
Concerted evolution, whereby individual members of a DNA family within one species are more closely related to each other than to members of the same type of DNA family in other species; Horizontal gene transfer, where genes are transferred from one organism to another by means other than genes received from an ancestor It is sometimes used by creationists as a synonym for
Microevolution, development of genetic changes below the speciation threshold
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