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Subject - biology, genetics

In biology, the term evolution (from Latin evolvere "to develop") describes the development of organisms through changes in their observable traits over a succession of generations. Biological evolution takes place in populations of lifeforms.

The notion that modern lifeforms come from a progression and that more complicated forms are descended from simpler ones became established in the sciences as early as the beginning of the 19th century. At that time, the phylogenic relationships were explained by various competing hypotheses. A comprehensive theory of evolution was first established by Charles Darwin with his seminal work "On the Origin of Species by Means of Natural Selection", in which he brought together all of the evidence available at the time and, most importantly, provided the first self-consistent causal explanation of the evolutionary process.

According to evolutionary theory, which is accepted by an overwhelming majority of biologists and is largely based on Darwin's idea, evolution is explained by two phenomena: the presence of genetic variability and the existence of selection mechanisms that favor certain genetic variations and retain them. Genetic variability results from random mutation and recombination events. How the resulting genetic variants then take hold depends on two evolutionary forces: (natural) selection, as it was described by Darwin, and certain random processes that are grouped together under the term "genetic drift".