Continuing the discussion from Gil grabs some ammunition and shoots down Doug Axe's 2004 extrapolation by a factor of more than 10^44:
I first heard of evolution in high school, introduced as an interesting and controversial topic (actually in a religion class). It was interesting, and seemed to explain a lot of what we see. But I made no commitment to the idea at that time.
Perhaps 3 years later, as an undergraduate in a biology class (not my major), I learned more about evolution.
I tried some mathematical models – I guess that was simple minded population genetics. But I couldn’t see how it could work. So I remained non-committal.
The problem for me, as I saw it at that stage, was the natural selection seemed to be a kind of statistical convergence. And statistical convergence would be too slow and not sufficiently innovative to account for what we see. And I didn’t see how mutations could fill in the gap, short of an implausible sequence of mutations (giving “hopeful monsters”).
I guess that’s roughly the objection of the Wistar conference, the objection of Fred Hoyle and the objection of so many creationists.
But I didn’t stop there. A few years later – probably when I was in graduate school studying mathematics, I read Watson’s “The Double Helix”. That’s about the identification of DNA as the molecular basis for genetics.
There wasn’t anything directly in Watson’s book that convinced me. But the evidence from genetics and how well the evidence from genetics fitted the Linnaeus classification made a pretty convincing case in support of evolution. What remained was for me to work out how it was all possible, in the light of my earlier doubts.
It took me a while to solve that puzzle. And it mostly wasn’t an urgent issue. I had already been persuaded that the evolution picture was broadly correct, even if I did not know how to connect the dots.
I eventually did work through that puzzle, at least enough to satisfy me. So I’ll now give my current view of evolution, which is quite a bit different from how I had originally thought that it was supposed to work.
My current view of evolution
It is a population that evolves. And there is some genetic variation within that population.
The environment is forever changing. It might get hotter or wetter. A new predator shows up. A food staple disappears. Another potential food source shows up.
The population must attempt to adapt to the changing environment. It is adapt or die. In order to adapt, individual organisms change their behavior. Some are more successful than others. That’s where the existing variation comes in. That some are more successful than others is roughly what “natural selection” refers to. The variants that are more successful at adapting to the changed environment will do better. If there is not sufficient variation in the population, then there is a greater risk of extinction.
I see biological innovation as mostly a response to a dynamically changing environment. The already existing variation within the population is part of what make that possible. However, as the population changes to adapt to the changing environment, that will tend to reduce the amount of variation present in the population. The role of mutation is to replenish the reservoir of variation. And the recombination during meiosis helps spread this variation around.
If you think there needs to be purpose involved, then look to the apparently purposive response of organisms, as they modify their behavior in an attempt to adapt to the changing environment.
