Saturday, June 12, 2010

Lamarckianism Anyone?



Today's "Close To Home" comic is a reminder that the idea of evolution being driven by the inheritance of characters modified by patterns of use and disuse of parts is still a popular, albeit a discredited one.

The following is a direct quote from the current Wikipedia treatment of the topic of Jean-Baptiste Lamarck:

"Lamarck constructed one of the first theoretical frameworks of organic evolution. While this theory was generally rejected during his lifetime,[ Stephen Jay Gould argues that Lamarck was the "primary evolutionary theorist", in that his ideas, and the way in which he structured his theory set the tone for much of the subsequent thinking in evolutionary biology, through to the present day.

Lamarck is usually remembered for his belief in the inheritance of acquired characteristics, and the use and disuse model by which organisms developed their characteristics. Lamarck incorporated this belief into his theory of evolution, along with other more common beliefs of the time, such as spontaneous generation. The inheritance of acquired characteristics (also called the theory of adaptation or soft inheritance) was rejected by August Weismann in the 1880s when he developed a theory of inheritance in which germ plasm (the sex cells, later redefined as DNA), remained separate and distinct from the soma (the rest of the body); thus nothing which happens to the soma may be passed on with the germ-plasm. This model underlies the modern understanding of inheritance.

Charles Darwin allowed a role for use and disuse as an evolutionary mechanism subsidiary to natural selection, most often in respect of disuse.] He praised Lamarck for "the eminent service of arousing attention to the probability of all change in the organic... world, being the result of law, not miraculous interposition". Lamarckism is also occasionally used to describe quasi-evolutionary concepts in societal contexts, though not by Lamarck himself. For example, the memetic theory of cultural evolution is sometimes described as a form of Lamarckian inheritance of non-genetic traits.

In contrast to the eventual general rejection of his proposed mechanism for evolution, Lamarck's seven-volume work on the natural history of invertebrates is recognised as a lasting contribution to zoology.

The honeybee subspecies Apis mellifera lamarckii is named after Lamarck, as well as the Bluefire jellyfish (Cyaneia lamarckii): a number of plant species have also been named after him, including Amelanchier lamarckii (Juneberry), Digitalis lamarckii and Aconitum lamarckii."

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