Microevolution

(redirected from microevolutionary)
Also found in: Dictionary, Thesaurus, Medical.

microevolution

[¦mī·krō‚ev·ə′lü·shən]
(evolution)
Evolutionary processes resulting from the accumulation of minor changes over a relatively short period of time; evolutionary changes due to gene mutation.
Evolution of species.

Microevolution

 

the aggregate of the actuating evolutionary processes occurring within isolated or neighboring populations of a given species. (Populations here are considered as the elementary evolutionary structure; mutations—the basis for genetic variation—as the elementary evolutionary material; and the mutation process, the waves of life, various forms of isolation, and natural selection, as the elementary evolutionary factors.)

Under the pressure of evolutionary factors, change occurs in the genotypic composition of a population—the leading actuating mechanism of the evolutionary process. The term “micro-evolution,” as counterposed to macroevolution, was once used by certain evolutionists to mean variability and the development of forms within a species. Modern microevolutionary theory developed after the synthesis of genetics and classical Darwinism. The basis for the theory was laid by the Soviet geneticist S. S. Chetverikov in 1926 and the English geneticist R. A. Fisher in 1930. In the modern view (sometimes called the synthetic theory of evolution), all of the basic actuating mechanisms of evolution on all levels occur within species—that is, on the microevolutionary level. Microevolution culminates in species formation—in other words, in the appearance of species that are reproductively isolated from the original and all other closely related species. For this reason, there are no distinctions in principle between microevolution and macroevolution, which differ only in their temporal and spatial scale.

Successful research on the microevolutionary level necessitates the synthesis of populational-genetic experiments and quantitative descriptions of the processes of population dynamics and ecology, study of ethological phenomena, analytical application of the theoretical propositions of genetics, and mathematical models of intrapopulational and interpopulational processes.

REFERENCES

Chetverikov, S. S. “O nekotorykh momentakh evoliutsionnogo protsessa s tochki zreniia sovremennoi genetiki.” Zhurnal eksperimentaVnoi biologii, 1926, vol. 2, issue 1.
Timofeev-Resovskii, N. V. “Mikroevoliutsiia.” Botanicheskii zhurnal, 1958. vol. 43, no. 3.
Shmal’gauzen, I. I. Faktory evoliutsii, 2nd ed. Moscow, 1968.
Mayr, E. Zoologicheskii vid i evoliutsiia. Moscow, 1968. (Translated from English.)
Mayr, E. Printsipy zoologicheskoi sistematiki. Moscow, 1971. (Translated from English.)
Timofeev-Resovskii, N. V., N. N. Vorontsov, and A. V. lablokov. Kratkii ocherk teorii evoliutsii. Moscow, 1969.
Fisher, R. A. The Genetical Theory of Natural Selection. Oxford, 1930.
Huxley, J. Evolution: The Modern Synthesis, 2nd ed. London, 1963.

N. V. TIMOFEEV-RESOVSKII

References in periodicals archive ?
Finally, it should be noted that the use of conditional lethals, while allowing observation of a microevolutionary change within a manageable period, may also unintentionally create or reinforce a belief that selection primarily occurs in gross mutants and in short time frames.
The lesson plan asks students to examine various debates over parts of evolutionary theory that are discussed in science journals, such as whether microevolutionary processes are sufficient to explain macroevolution.
Adequate typing methods are also crucial to determine the degree of relatedness of bacteria and to enable the reconstruction of microevolutionary events (7).
Catley (2006) suggests that the educational emphasis on microevolutionary processes has left both teachers and students with a poor understanding of macroevolution and speciation.
So, for example, in this volume one is given the opportunity to have Kim Sterelny provide a guided tour through the complex relationship between microevolutionary processes and macroevolutionary patterns in the context of the radiation of animal life during the so-called 'Cambrian Explosion'.
These include many of the microevolutionary principles such as population genetics, genetic drift and gene flow.