sorry - just a brief off-topic response
bumble wrote:
Species have been known to breed itself into extinction by selecting the wrong traits and focusing on the wrong attributes (giant irish deer i think is one example of that...you will need to check the species name but they were so fussy about choosing large antlers that over a period of time they became so big the deer could not function normally anymore and impaired their own survival as a result). We assume that natural selection is always right and that it always chooses the superior model...this is most likely not so...
it is only speculation that Irish Elk went extinct because the species naturally selected antlers that were either too big to move through the forest or too heavy to hold heads upright. this view disregards other possible factors such as hunting (as with the other megafauna of the time) or climate-related habitat change. it seems to me more logical that IF antlers were starting to get so large they were becoming hindrances to the mating process (or even life processes in general) that selection would start to go the other way, or at least level off, as those males with less than the hugest antlers would then have a better chance of reproducing.
AFAIK humans are the first species with a good shot of self-extincting.