[Con X-Poser]

<< keep rubbing you thumb on sandpaper, sooner or later you'll have a calous. Have the next 500 or so generations do the same, and you'll start having babies with reinforced thumb skin. It's just how it works, nature/need always drive evolution. >>

Just like over 500 generations of circumcision among Jews produced pre-circumcised babies, right?

Lamarck lives on Free Republic!

[Jael]

Walking dead said
keep rubbing you thumb on sandpaper, sooner or later you'll have a calous. Have the next 500 or so generations do the same, and you'll start having babies with reinforced thumb skin. It's just how it works, nature/need always drive evolution.

XMan said
Just like over 500 generations of circumcision among Jews produced pre-circumcised babies, right?

Jael cracked up at the flawless logic. IT WAS GREAT!!!!!!!

[Nataku X]

Okay, so maybe walkingdead used a bad example. If, however, those with a callused thumb lived much longer and produced more progeny than those without, then, indeed, you would see babies being born with thicker skin. Same thing with circumsion.

There are some humans who seem to be immune to heart disease. If we put everyone on a diet of McDonald's, and we allowed everyone with heart disease to die, then we would see a larger percentage of people who were immune to heart disease over time.

But the fact that we have medical care has removed nearly all "pressure" on humans. So we probably won't see any change in genetic frequency in humans for a while...

It's simple logic--no one disputes it. What you want to prove for your side, however, is that the genetic pool cannot produce enough information or mutations, and does not have enough variety, to readily "adapt" to different selective pressures. In other words--genes cannot readily yield people with calluses or people without foreskins.