jean - baptiste lamarck proposed a theory of evolution based on acquired characteristics.
jean - baptiste lamarck proposed a theory of evolution based on acquired characteristics.
who proposed a theory of evolution based on acquired characteristics?
jean - baptiste lamarck
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jean-baptiste lamarck's 1809 evolutionary theory, transmutation of species, was based on a progressive (orthogenetic) drive toward greater complexity. lamarck also shared the belief, common at the time, that characteristics acquired during an organism's life could be inherited by the next generation, producing adaptation to the environment. such characteristics were caused by the use or disuse of the affected part of the body. this minor component of lamarck's theory became known, much later, as lamarckism. darwin included "effects of the increased use and disuse of parts, as controlled by natural selection" in "on the origin of species", giving examples such as large ground feeding birds getting stronger legs through exercise, and weaker wings from not flying until, like the ostrich, they could not fly at all. in the late 19th century, neo-lamarckism was supported by the german biologist ernst haeckel, the american paleontologists edward drinker cope and alpheus hyatt, and the american entomologist alpheus packard. butler and cope believed that this allowed organisms to effectively drive their own evolution. packard argued that the loss of vision in the blind cave insects he studied was best explained through a lamarckian process of atrophy through disuse combined with inheritance of acquired characteristics. meanwhile, the english botanist george henslow studied how environmental stress affected the development of plants, and he wrote that the variations induced by such environmental factors could largely explain evolution; he did not see the need to demonstrate that such variations could actually be inherited. critics pointed out that there was no solid evidence for the inheritance of acquired characteristics. instead, the experimental work of the german biologist august weismann resulted in the germ plasm theory of inheritance, which weismann said made the inheritance of acquired characteristics impossible, since the weismann barrier would prevent any changes that occurred to the body after birth from being inherited by the next generation.
alternatives to evolution by natural selection