acquired characteristics

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acquired characteristics Characteristics that are acquired by an organism during its lifetime, according to early evolutionary theorists (e.g. Lamarck and Buffon). Lamarck further suggested a kind of directional, non-random evolution, in that traits acquired in one generation as a result of behavioural changes in response to environmental stimuli would be transmitted to the gametes and inherited by the next generation. Thus, over several generations, a particular type of organism would become better adapted to its environment. The kinds of acquisition envisaged by Lamarck and their heritability are now discredited, although organic selection simulates them.

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acquired characteristics Characteristics that are acquired in the lifetime of an organism, according to early evolutionary theorists such as Lamarck. Lamarck further suggested that traits acquired in one generation in response to environmental stimuli would be inherited by the next generation. Thus over several generations a particular type of organism would become better adapted (see ADAPTATION) to its environment. The kinds of acquisition envisaged by Lamarck and their heritability are now discredited, although there has been a recent revival of some aspects of Lamarckism in modified form.

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acquired characteristics The characteristics that are acquired in the lifetime of an organism, according to early evolutionary theorists such as Lamarck. Lamarck further suggested that traits acquired in one generation in response to environmental stimuli would be transmitted to the gametes and inherited by the next generation. Thus, over several generations a particular type of organism would become better adapted to its environment. The kinds of acquisition envisaged by Lamarck and their heritability are now discredited, although there has been a recent revival of some aspects of the theory in modified form.

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acquired characteristics Characteristics that are acquired by an organism during its lifetime. According to early evolutionary theorists (e.g. Lamarck), traits acquired in one generation in response to environmental stimuli may be inherited by the next generation. Thus over several generations a particular type of organism would become better adapted to its environment. The heritability of such characteristics is now discredited.

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acquired characteristics, modifications produced in an individual plant or animal as a result of mutilation, disease, use and disuse, or any distinctly environmental influence. Some examples are docking of tails, malformation caused by disease, and muscle atrophy. The belief in the inheritability of acquired characteristics, proposed by the French biologist Jean-Baptiste Lamarck in 1809, was widely accepted at one time, but is now rejected. Geneticists have affirmed that inheritance is determined solely by the reproductive cells and is unaffected by somatic (body) cells.

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acquired characteristics Features that are developed during the lifetime of an individual, e.g. the enlarged arm muscles of a tennis player. Such characteristics are not genetically controlled and cannot be passed on to the next generation. See also Lamarckism; neo-Lamarckism.