This is not evolution. A person who gets brest implants or a person who becomes massively strong by weight training will not give birth to buxom or musclebound children. Evolution is a genetic occurance, not something we do to ourselves, and those changes will not be passed on to the next generation.Originally Posted by jaderabbit
As for the people in asia that can see underwater just as well above, I haven't heard about that. All I can say is maybe it's possible. One thing that must be remembered and has been mentioned in other threads is that evolution is not linear, and it doesn't occur because of what we need. I'm finding that this is a rather general misconception about the concept. The same goes for natural selection and survival of the fittest. Survival of the fittest is the mechanism of natural selection, but it refers to the ability to sexually reproduce.
In a changing environment, sometimes a species will be thrust into a circumstance where it will be hard for it to survive. I'll use the giraffe for this one. Giraffes have always been tall, right? Wrong. There used to be both small and tall giraffes until their more low lying food source died out. The result was that the tall giraffes able to reach leaves on trees survived, and the small ones did not. However, that genetic data still occurs in giraffes, and once in awhile you will still see a short giraffe born. The giraffe didn't survive by changing at this point, it survived because the genetic variance necessary to survive already existed in its species.
In order for humans to evolve like the giraffes did, something would have to happen that occurs on a world wide scale which threatens the species. Right now, I think the most likely cause of evolution in our species will be AIDS, in which the only people who survive are the ones that lack receptors on the bottoms of their white blood cells and thus are carriers but are immune to the disease. If no cure for aids is discovered (assuming you are unable to controle the spread of the virus) then at one point it is resonable to assume that everyone in the world will have AIDS, and only a certain type of people with the immunity to it will survive. What's funny, is aids will still be around, but it'll be just like any other of the harmless viruses and bacteria in our bodies.
In order for evolution to occur by mutation, the population would have to be small enough that the mutation doesn't get weeded out because of genetic variance in the group. Well, humans like to travel, humans love eachother, and humans love their sex. I can see mutation occuring in a small fishing village in asia, but we're talking about a pretty hefty mutation here. Mutations are rarely beneficial. I'll do some studying on that tonight.
Edit: Not to mention most mutations that have a beneficial affect in some scenarious (sickle cell anemia, being one) are kind of a double edged sword. Children born with a homozygous recessive trait for sickle cell don't usually make it to adulthood in the places where having the heterozygous trait is beneficial. For those of you wondering, sickle cell grants some resistance to malaria.