acquired characteristics

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.

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.

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.