BIOL 2200 Lecture Notes - Lecture 2: Thomas Robert Malthus, August Weismann, James Hutton
20 Jan 2017
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Aristotle: described species as fixed, life needed organizing, a scale from simple to complex (led to idea that there are lower order organisms and higher order organisms) James hutton: slow transformation of earth and earth was old than thought at the time (gradualism) In optimal conditions, organisms have lots of offspring, but not all offspring survived: offspring limited by post-birth conditions, human population limited by resources. Idea that we can see changes in expression of genes (not gene itself) that can be passed onto offspring. Methylation of gene (turns gene on or off) No evidence that methylation happens in a population. George cuvier: first person to bring up idea of extinction, still thought organisms are fixed, extinction happens when catastrophic events occur, similar organisms are because of immigration. Charles lyell: earth"s la(cid:374)ds(cid:272)ape (cid:272)reated (cid:271)y s(cid:373)all gradual changes. Alfred russell wallace: had similar ideas about natural selection. Natural selection favors individuals that are adapted to particular environment.
