graceadieu
Posts: 1518
Joined: 3/20/2008 From: Maryland Status: offline
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quote:
ORIGINAL: Milesnmiles Then one day I was asked, how long did it take for birds to evolve? I said thousands of years. Were there predators during that time? Sure, there were predators. Then how did the "proto-birds" exist long enough develop flight? Uh, the same way any other organism survives predators.... quote:
I thought although scientifically birds could have evolved, realistically, fat chance. Well, there's extensive fossil evidence. quote:
What about bisexual reproduction? With asexual reproduction Evolution would seem reasonable but with bisexual reproduction that means every time evolution made an advance, it couldn't produce just one of a new type, it now had to produce two, male and female, within about 50 miles of each other and within several years of each other. Again scientifically it could happen but realistically, fat chance. That's not how population genetics works. The individual with the "advance" (genetic mutation) will still be able to reproduce with the other members of their species, passing it along to at least some of his or her kids. If it's actually an "advance" - that is, if it improves an individual's ability to survive and reproduce - that individual will be more likely to have more kids, and those kids will have more kids, until the gene spreads throughout the species. quote:
Finally, what about "the spark of life", it has always seemed a bit sketchy to me. Chemicals mixing in a mud puddle struck by lightening and suddenly life. Whereas human scientists working under laboratory conditions have not duplicated it They have, more or less. Back in the 50s, scientists found if they take the chemical mixture that existed on the early Earth and zap it with electricity (lightening) a bunch, the organic compounds that form the basis of life spontaneously form. And then, another experiment in the 60s or 70s found basically that if you take those compounds and do some natural process to it (I don't recall off the top of my head), they spontaneously form into self-replicating genes. Now, since scientists don't have millions of years to do their experiments, going from A to B to C to cell hasn't yet been done in a lab setting, but every indication is that if you continue the process from "soup" to organic compounds to genes for long enough, eventually you'll get to cells.
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