caravelair

i'm just curious, but i've heard it mentioned that lamarckianism was some sort of pre-darwin idea about species, but i don't know what it is. so... can anyone give me the gist of it?

acidphos

In common language the gist of Lamarckism is that acquired phenotypes are passed on-

i.e. If I stretch my arms out by being kinky and having my wife strap me up on a rack then my children will also have long arms.

However, in checking I came across a Lamarck bio site that makes his ideas not seem to ridiculous.

"a change in the environment causes changes in the needs of organisms living in that environment, which in turn causes changes in their behavior. Altered behavior leads to greater or lesser use of a given structure or organ; use would cause the structure to increase in size over several generations, whereas disuse would cause it to shrink or even disappear."

edit: formatting correction

Kevbo

Of course, Lamarck was right in regards to environmental pressure, but he got the mechanism wrong. Those organisms which are suited survive an environmental change pass on their genes, which increases the frequency of certain alleles in the population.