Re: [asa] Two questions

Hi all,

Thanks for the answers. I should make it clear I claim no expertise here nor do I claim to have *the* answer(s). But why let that stop me from spouting off?

In my opinion, the two questions are related. Koonin identifies two principal concepts of the Modern Synthesis as follows:

- Fixation of (rare) beneficial changes by natural selection is the main driving force of evolution that, generally, produces increasingly complex adaptive features of organisms.

- The variations fixed by natural selection are 'infinitesimally small'. Evolution adheres to gradualism.

Thus, I don't think observations about blending theory or Lamarkianism apply. Those might partly explain Darwin's thinking, but they fail to explain the Modern Synthesis - its commitment to gradualism and its original rejection of Neutral Theory.

My guess is that Darwin, like so many other great scientists, was greatly influenced by Newton's success in finding a small number of simple laws that explained just about everything. In other words, Darwin and the architects of the Modern Synthesis, sought a simple, elegant explanation for all of evolution. And in this Explanation, natural selection was supposed to be ubiquitous because then natural selection would exist almost as a Law.

So Darwin would insist on strict gradualism because it meant that Natural Selection was effectively omnipresent, always scrutinizing every bit of variation that popped into existence. And we can change Koonin's observation, "the Modern Synthesis, in its 'hardened' form, effectively, rejected drift as an important evolutionary force, and adhered to a purely adaptationist model of evolution" to ""the Modern Synthesis, in its 'hardened' form, effectively, rejected drift as an important evolutionary force *because it* adhered to a purely adaptationist model of evolution." The "purely adaptationist model of evolution" comes from viewing natural selection as omnipresent and the existence of drift as an important evolutionary force denies such omnipresence.

The advantage to my explanation is that it answers both "why?" questions with great parsimony.

- Mike

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Received on Wed Apr 15 22:31:47 2009