Test My Theory: Macro evolution DOES happen?

[Gawdzilla Sama]

I was discussing a known rapid one-gen "macro" evolution as a possible response to the creationist claim that we NEVER see "macro" changes in species, and the implications for the specimen's chances for successfully passing on that mutation.

Unfortunately, that's not highly likely. Your 2-headed cow example is a good one as gross mutations can & do occur. In the main though, they're likely to confer little/no advantage but that doesn't mean that they can't; it all depends on environmental & social selection pressures and if they're favourable, the mutation is passed and the allele frequency increases. However if you think of things the other way round, you get a better argument. I assume you've heard of recidivisms? Sometimes humans are born with tails because we still have the genes within us and sometimes random mutations will result in expression of such genes when normally they wouldn't. That's a perfect demonstration of 'macro' evolution.

I don't expect to convert creationists, of course, but I never hoped for that. I wanted to have a handy counter to their claim for the fence sitters.