Re: Lamarckist Contradiction

Susan S. Chin (susansf@netcom.com)
Wed, 20 Nov 1996 07:13:43 GMT

Rabbi Bruce Cohen (ravbar@mail.idt.net) wrote:
: Larmarckism (the belief that the genetic material of a species can be
: altered by the external, non-radioactive, non-chemical influences of
: its enviromment, such as climatic changes), is false.

Lamarckism, as I understand it, is one of the early attempts to explain how
evolution could have produced the diversity seen in nature. Keep in mind
Larmarck's ideas were put forth in the late 1700's, before Darwin's
theory of Natural Selection. Lamarck was one of the first to propose a
mechanism for evolution, unfortunately he was wrong. His theory is as
follows: Evolution is a constant strive towards "perfection." Organisms
acquire new characteristics in their lifetime by using (or not using)
certain parts of their bodies. These newly acquired characters are passed
on to their offspring (if favorable).

Obviously this doesn't occur. Evolution does not occur at the organismal
level, rather the populational. But give Lamarck some credit, there
wasn't a whole lot for him to work with in the 1700's in terms of
evolutionary theory. He did recognize the role of change in evolution,
but didn't have Mendelian genetics to work with in developing his theory.

: So why are we getting discussion about climate changes producing
: changes in the pedal architecture of primates? Are there hidden
: Lamarckists among us? The fossil record does not justify at this point
: the conjecture that climate change somehow yielded a biped, because
: bipedalism would make for better scavengers than quardrapedal, or
: semi-erect ape-like locomotion. There are no transitional forms in the
: fossil record to make such conjecture justifible publicly, are there?

The explanation that climatic changes and resultant environmental,
ecological changes require that organisms, and populations must adapt
through time to the new, changing environments. Over time, certain
adaptations are more advantageous in this new environment. Differential
reproduction, survival rates. Natural selections occuring... In this
context, bipedalism could have been one of those adaptations that proved
advantageous over that of the other apes.

As for transitional forms.. would a bipedal hominid with very chimp like
cranial and dental morphology count?

Susan 

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                                             susansf@netcom.com