Saturday, January 26, 2008

I'm too sexy for my brain.

So oddly enough another debate on I managed to stump some creationist by posting a well documented easy explanation of evolution with a number of topical notes as to how exactly it all goes together. Explaining why there are marsupials Australia. He apparently tried for a bit and ended up posting several questions to me. You know, you see the same arguments being cut and pasted so many times you neglect to realize that there is a real person who really believes those arguments doing the cutting and pasting... and he's really stupid.

--"first were did the orginal orginism come from?"

I don't know. We have some generally good ideas as to some of the steps involved. There are easily generated organic molecules, fantastic catalysts, tiny easily produced replicative molecules, strong evidence that DNA even at very short lengths is fairly crystalline (crystals have a simple replication). Outside of these good suggestions we just don't know; I don't know.

--"how do you figure in the great flood?"

I don't. The great flood is a myth. There's no evidence geologically, biologically, historically, plausibly that it occurred. There was a time when geologists actually believed it, but a preponderance of the evidence made even the most ardent of finally admit that there should be some evidence and clearly was not. For example, we have societies which show continuous existence during the time of this supposed flood. The oldest living thing on the planet is a Creosote bush in the Mojave desert 11,700 (5,700 years older than the universe) years old. Further, we have uninterrupted tree ring records from all over the world going back about 11,000 years. Further, floods leave a very distinctive mark in the rocks. Just as we can tell that some globally bad thing happened by looking at rocks 64 million years ago from anywhere on the Earth, a local flood would leave a similar mark on our geology.

-- "how do you figure that this earth of ours just came about by chance with all the thins that had to be so perfect for us to live?"

If the Earth didn't exist in such a fashion to allow life to arise it would be impossible to be here and ask that question. There are 70,000,000,000,000,000,000,0000 stars in the universe. Probably a good number of planets around those stars. The fact that life arose on a planet which life could arise on is of very little mystery. Also, to say that the planet is perfect for us is a bit like saying my hand is perfect for a glove. We evolved on this planet and so we are well adapted to the changing conditions. Further, our species is unique in that we adapt not only to our environment but have adapted our environment to us. You'll find humans in the eastern part of the US living happily even though that part of the country is pretty frozen.

--"why are we the most advanced species?"

We aren't. Evolution doesn't work that way. It isn't a race to some advantageous goal it's a bootstrapping little edges to drive a population. There are far fewer organisms existing than could exist, if you look at the breeding patterns of any organisms from bacteria, to rabbits, to insects, to humans you find that within a short number of years it should be possible to coat the planet. However, there's a struggle for resources and different members of different species fight for their own advantages. Sometimes small genetic tweaks will cause an organism to be slightly better or worse in this struggle. The worse organisms are quickly driven extinct whereas the slightly better organisms will use this edge in their struggle to survive passing on this improved genetic characteristic to more offspring and becoming a major factor in the species. This doesn't say anything about a species being the most advanced or the best. Every species is as well adapted within their struggle to survive as humans are adapted within our struggle to survive. There's nothing inherently superior about humans over rabbits, over grass, or birds. We are just as adapted towards our survival as they are towards theirs. There isn't a goal in evolution so the suggestion that we are closer to that goal than lions is a rather misguided idea. Lions are adapted to their struggle and we are adapted to ours. Generally organisms occupy different niches so it's a lot like apples and oranges... apples are adapted to their niche and oranges to theirs.

-- "why dosnt all mothers have 14 arms? (because they would notice the need for another arm and that magic process would go into effect.)

Evolution is not a magical process. It's a gradual process. If you could gradually require the addition of an arm from a fairly pointless arm stub to a fully functional arm you could evolve one. However, our general body plan is the same as all vertebrates fish had two front fins and two hind fins so now all species originally evolved from fish have this same general plan and gradual modifications (a major change is nearly impossible to occur and be helpful to an organism). Slow gradual change, tweaks which give slight edges to organism in their struggle within their species.

He moved on to the topic of the Big Bang.

The scientific evidence does lead one to accept that the universe began 14 billion years ago from an original point. I highly recommend Richard Carrier's piece on why he was a Big Bang Skeptic and the scientific evidence behind it explaining why he accepts the theory now.

-- "if that tiny ball of matter was so hot wouldn't it purge it of all living organisms?"

It's worse that that, it wouldn't have been able to become matter for a while. It would have been impossible to have any complex structures at all. However, the Big Bang does not contain living organisms. Those come far later. The universe is 14 billion years old. Our planet is 4.55 billion years old, our sun is a little older than that (few hundred million years or so). However life didn't come on to the scene until about 2 billion years ago. So as far as we can tell the entire universe was lifeless for 12 billion years. Complex life has only been around for about .6 billion, and we've been around for about .001 billion years (high estimate 100,000).

--"if not why do we get sun burns?"

Sun burns are actually burns. The UV rays of the sun actually damage the our skin. Life in the struggle for survival has developed slow gradual tweaks which allow for protection from the sun to reduce the damage to our skins from over-exposure to sun light. However, where light is less abundant (such as northern Europe), lighter skin evolved as a little tweak to increase the production of Vitamin D. Vitamin D is an extremely useful molecule for our development and is produced when UV light hits our skin. So the previous adaptations of increased melanin to protect the skin from the light were not as advantageous in northern environments. So when the gene used for melanin transport in the skin would break (as tends to happen here and there) it became one of those edges in struggle for survival in the northern environment allowing people to produce more Vitamin D. Because of the reduced sun effects the necessity of protection from sun burn was lessened. However, when you move people adapted for dimmer climates (adapted towards Vitamin D production rather than UV protection) into more sun rich climates they aren't as well as adapted as their darker skins cousins resulting in sun burns.

It's similar to Kettlewell's peppered moths experiments where the lighter colored moths were better adapted to one environment (lighter color trees) and darker colored moths were better adapted to another (darker color trees). Slight adaptations to slightly different environments. If you put the lighter color moth on a darker color tree it has a noticeable disadvantage. In the moth's case it's increased predation by great tits in the case of humans it's sunburns.

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