Re: [asa] Millions of years population growth

On the punctuated equilibrium example, a couple of letters to the
editor to Nature questioned whether the observed events were actual
speciation versus environmental shifts that brought about
ecophenotypic variation [i.e., change in form within a species due to
environmental differences]. (I know because I recently looked them up
because I was interested in the species they used as examples, not
because I have Nature contents memorized). There are good examples of
punctuated equilibrium in mollusks, but this particular one has been
questioned.

Perhaps the simplest way to address the linear population growth claim
is to point out the impact of factors such as medical improvements,
agricultural innovations, etc. Most people have a vague idea that the
plague made a noticeable dent in the human population a few centuries
ago, which contradicts the constant growth model.

Darwin actually was a bit careless with exact data on the Beagle, e.g.
which island in the Galapagos things came from. Of course, this made
it harder for him to see the patterns pointing to evolution, so it
doesn't support what AIG wants it to.

The claim that mutations are overwhelmingly negative is a popular
antievolutionary lie. Most mutations have no effect (unless one
counts varying evolutionary potential). The probability that a
mutation with effects will be positive or negative depends on how well
suited the gene in question is for the purpose in question.

Also, it's rarely positive mutation that's needed to make a new
species, but rather a neutral change that shifts breeding cues,
habitat preferences, etc. from one viable option to another. Not to
mention the fact that unlike some old-earth antievolutionists, many
young earth advocates have endorsed evolution of new species as a way
to need fewer spaces on the ark.

-- 
Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"
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