Re: Please help me defeat a creationist argument!
Quick read of the article. The 200 base pairs change comes from a 4% difference but you'll notice the figure for functional DNA (stuff that contributes to differences rather than useless) is only 1.2%.
Second, (tho I'm not positive of this), the chimp isn't our closest ancestor and so isn't the 'starting' point for the time frame given.
Third, the frickin' chimp is evolving too. It makes half the changes, we make half the changes so we go from a common ancestor to man today and chimp today. Of course, it needn't be half and half.
Fourth, there's nothing to say mutations can't happen in groups, natural selection acts after the changes have happened.
Fifth, we're under different selection pressures now. When we first came down out of the trees we encountered a totally new evironment and so the selection pressure was huge. We've adapted now so the rates of change are different.
Ok, I'll stop here because these are just thoughts rather than me having any detailed knowledge.
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