Evolution and Abortion....

[In A Perfect World]

You are talking about two concepts... they don't even contradict.

If humans abort every baby, then they won't be around for another generation, plain simple! Another species on our planet wiped out...

What's your point exactly? That evolution doesn't happen?

 

[Cirbryn]

The height versus nutrition thing is hardly evolution. Take an average American kid and malnourish them and they'll end up short too. Yes, certain strains of humanity are shorter then others, but evolution hasn't adjusted are height at all, merely diet.

It's been surprisingly difficult to find actual studies on this. Most of what I found talks about changes in height in the last couple hundred years, which would support your argument since evolution would be expected to take longer. On the other hand there are several obvious tests of the nutrition argument, such as comparing heights of undernourished present day populations to heights in the past, or comparing heights of historical privileged classes to now, and I haven't found any of those. This study (abstract only)also mentions improvements in medicine and warming temperatures as possible explanatory factors, which makes sense.

Right. I remember that article in Scientific American about how they found how to turn on and off muscle growth in cows with simple gene therapy. How much selective pressure is there going to be when anyone can get the muscles of a professional body builder with a little gene therapy? Technology goes to the elites first, yes, but gene therapy will be used for a whole lot more then correcting a few diseases (using it to correct diseases alone is like having the sole use of the electric motor being mechanized wheelchairs).

You don't think all that muscle growth in cows wouldn't be accompanied by some drawbacks if applied to humans that want to live longer than a few years? Steroid abuse will give you some pretty impressive muscles too. But even supposing you're right, that doesn't mean humans will stop evolving, it just means a particular selective pressure will be lessened, same as for when eyeglasses became generally available. The lessening of that selective pressure will mean an increase of alleles that the new genetic therapies would help address. (Unless you think those therapies are going to result in changes that will be passed on to progeny? My assumption was that they would involve activation of genes present in somatic cells.) Anyway, that increase of alleles in the population is evolution.

 

[Cirbryn]

Yes, it is obvious that this thread confuses evolution and social darwinism.

No it doesn't. See my comment on this in post 34.

It should be obvious to anyone who understands the concept of evolution that sentient beings (ergo humans) don't "evolve" but (theoretically) rationally choose their mates.

Well I'd like to think I understand it pretty well, and what's obvious to me is that "rationally" choosing mates (not that we do that anyway) is not going to prevent evolution. This article discusses two genes linked to brain size that are increasing in frequency in the population even now.