Originally posted by AThousandYoungdid natural selection make dogs into so many different breeds? no, humans and human society did. humans do not experience differential success at reproduction due to random variation within the gene pool. humans are all pretty successful at reproducing because of the drastically increased ability to feed and care for the great majority of humans. the difference between humans that successfully reproduce and those that do not has more to do with circumstantial cosiderations than individual attributes. - except for extreme circumstances. obviously a person born with a fatal childhood disease will be selected against by natural selection, but for the most part humans have transcended natural selection.
Natural Selection acts on humans just as it does any other organism. For example, people born with genetically deficient immune systems will tend not to reproduce as well as others.
Originally posted by nomindNo artificial selection did.
did natural selection make dogs into so many different breeds? no, humans and human society did. humans do not experience differential success at reproduction due to random variation within the gene pool. humans are all pretty successful at reproducing because of the drastically increased ability to feed and care for the great majority of humans. the diff ...[text shortened]... d against by natural selection, but for the most part humans have transcended natural selection.
humans do not experience differential success at reproduction due to random variation within the gene pool
Of course we do. Are you saying that sickle cell anemia is not caused by differential success due to random variation? You really believe humans don't follow the same evolutionary laws other organisms do? People in the Scandinavian nations have very little lactose intolerance because they have been drinking milk almost since they got there from Africa. Humans have spontaneous genetic variation like any other organism, and are in an environment which will favor certain traits over others. We will evolve to reduce the main causes of death or infertility before 45 or so. Now of course man controls some of those factors consciously (genetic screening), and in the future will be able to artificially select more and more, but there's going to be always some element of natural selection too. That is unless we go into a future age in which scientists control the genetic makeup of people down to the last gene and can detect cure any concievable genetic disease easily...freaky!
Originally posted by nomindThey are tougher than me? I very much doubt that.
there is no survival of the fittest with humanity. those african children are a thousand times tougher and more adaptable than you. you just happen to have been born in an industrialized country which is your good luck. i could go beat a dozen individuals to death before i was stopped but this physical advatange of mine means nothing because of the social institutions that we have established.
The forces acting on the evolution of a species is not just natural selection based on viability of the organism. Environment and just plain chance have a very large effect on survival. However to say that natural selection does not take place or is insignificant amoung either humans or dogs would be wrong and I think even creationists would agree on that as it fits into thier definition of microevolution. If natural selection was not taking place we would have far more genetic diseases than we currently observe amongst both species and dogs in particular would possibly exhibit a far greater range of shapes and sizes but due to natural selection some have prooved to be just not viable.
ok, the more i think about it, i realize that i am still thinking of natural selection with humans. i was putting too much emphasis on the artificial environmenmt and social situations that humans exist in. within those structures though, it is natural selection at work. i concede.