Definition of evolution
1a : descent with modification from preexisting species : cumulative inherited change in a population of organisms through time leading to the appearance of new forms : the process by which new species or populations of living things develop from preexisting forms through successive generations Evolution is a process of continuous branching and diversification from common trunks. This pattern of irreversible separation gives life's history its basic directionality.— Stephen Jay Gould also : the scientific theory explaining the appearance of new species and varieties through the action of various biological mechanisms (such as natural selection, genetic mutation or drift, and hybridization) Since 1950, developments in molecular biology have had a growing influence on the theory of evolution. — Nature In Darwinian evolution, the basic mechanism is genetic mutation, followed by selection of the organisms most likely to survive. — Pamela Weintraub
b : the historical development of a biological group (such as a species) : phylogeny
2a : a process of change in a certain direction : unfolding
b : the action or an instance of forming and giving something off : emission
c(1) : a process of continuous change from a lower, simpler, or worse to a higher, more complex, or better state : growth
(2) : a process of gradual and relatively peaceful social, political, and economic advance
d : something evolved
3 : the process of working out or developing
4 : the extraction of a mathematical root
5 : a process in which the whole universe is a progression of interrelated phenomena
6 : one of a set of prescribed movements
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