Sunday, March 05, 2006
Lamarckian mechanisms in Darwinian evolution
[Jablonka, Lamb, Avital, Trends in Ecology & Evolution, May '98]
Opening paragraph:
Lamarckism and Darwinism are traditionally seen as alternative
theories trying to account for evolutionary change. The verdict of
history is that Lamarck got it wrong - evolutionary change does
not occur through the inheritance of acquired characters. Acquired
characters are the outcome of instructive processes, such as those
seen in embryonic induction, transcriptional regulation, and
learning all of which involve highly specific and usually adaptive
responses to factors external to the responding system. The
inheritance of the outcomes of instructive processes is deemed to
be impossible. Adaptive evolutionary change is assumed to be based
on darwinian (or more accurately neo-darwinian) evolution in which
guidance comes exclusively from selective processes. The
production and nature of heritable variation is assumed to be
uninformed by the environment or by previous history. The future
is open-ended, determined solely by the contingencies of life. lt
is neither foretold nor intimated.
technorati tags: ecology, evolution, lamarck, inheritance
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