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Ok, I concede the point that all of evoloution is based off of mutations.
AAAAAAAAAAAAAAAAAAARGGGGGHHH! Don't be so quick to accept everything people say... even Ned (though most of what he says is platinum).
I firmly believe in evolution, and so far it appears that genetic mutation is an important mechanism of evolutionary change, with genes also being an excellent record of that change over time.
HOWEVER, this does not mean that genetic mutation is the ONLY mechanism and so ALL of evolution is due to genetic mutation.
One of the serious competitors to the genetic mutation theory of evolution, is symbiotic theory by Lynn Margulis. While it does not at to replace all genetic mutation as a source for evolutionary change, it shows that there are other mechanisms.
In Symbiosis, different organisms can gradually become a necessary part of each other's lives and thus merge into a new "species". This has gotten some very good supporting evidence, and suggests that perhaps most of evolution from prokaryotes to eukaryotes was symbiosis rather than mutation. Margulis seems to make a solid point that this could also play a part in eukaryotes evolving into more complex plants and animals, and perhaps the evolution of complex animals into yet more complex species.
Its those last two stages which are not very well defined though, and Ernst Mayr (in his forward to one of her books) seems to want to keep her enthusiasm in check on those possibilities.
Here are three links that can help you with learning more about symbiosis:
Lynn Margulis Bio
Good basic overview of Symbiosis
Margulis's best book on the subject... Though the link is to amazon, I am not suggesting you buy it. You can probably find it in a library (that's where I found the copy I read). I just thought the link would give you a good pic of the cover and some info about the book.
As for your question of what % are based on symbiosis vs genetic vs as yet possibly undiscovered mechanisms... I have no idea. Clearly if symbiosis is the major factor in evolution of simple organisms, while genetic is the major (or sole) mechanism in complex organisms, then the percentage would be skewed to symbiosis due the vast larger numbers of simple organisms. But I think that would be misleading.
Frankly I think this will always remain guesswork.
[This message has been edited by holmes, 02-13-2004]
holmes
"...what a fool believes he sees, no wise man has the power to reason away.."(D. Bros)
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