Medical Dictionary
Main Entry:
La·marck·ian Pronunciation:
l&-'mär-kE-&n Function:
adjective : of or relating to Lamarckism
Laámarck /lä-'märk,/ Jean–Baptiste–Pierre–Antoine de Monet de (1744–1829), French botanist and biologist. As a botanist Lamarck produced voluminousbotanical writings. As a biologist he made substantial contributions to comparative anatomy and the study of invertebrates. In 1801 he introduced his classification of invertebrates, a classificationthat remains largely accepted. From 1815 to 1822 he published his major work, a multivolume natural history of invertebrates. He is credited with being the first to distinguish invertebrates as ataxonomic group from vertebrates. In 1809 he published a work summarizing his views on zoological philosophy. Here he presented two major “laws”: (1) organs are improved with repeated useand weakened by disuse (2) new characteristics are acquired through interaction with the environment and are passed on to progeny. Although his general idea of evolutionary change was latercontroverted by Darwin, Lamarck is important because his thesis denied the old notion of the immutability of species, thereby preparing the way for later explanations of the transformation andevolution of plants and animals.
[luh-mahr-kee-uh
n] 