Once again, I am going to ask the old chestnut: how could free-will evolve?
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Yes, it's another damned evolution question...
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Originally posted by Elok
Well, UR, my point about the propagation was that the development of new species involves, naturally, a change in DNA. Different species tend to have different numbers of chromosomes(don't goldfish have 96 or something ridiculous like that?).(\__/) 07/07/1937 - Never forget
(='.'=) "Claims demand evidence; extraordinary claims demand extraordinary evidence." -- Carl Sagan
(")_(") "Starting the fire from within."
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Originally posted by Rogan Josh
Once again, I am going to ask the old chestnut: how could free-will evolve?(\__/) 07/07/1937 - Never forget
(='.'=) "Claims demand evidence; extraordinary claims demand extraordinary evidence." -- Carl Sagan
(")_(") "Starting the fire from within."
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Urban:It depends. Not all species have a unique number of chromosomes. In fact, species closely related, such as the Great Apes, have the same number of chromosomes. In other words, there are all sorts of mutations and not all of them involve making an extra copy of a chromosome.
I think the answer is the same you get pretty much every time you consider mutations: that an extra chromosome isn't always detrimental. Most of the time, even overwhelmingly so, but every once in a while you get an extra chromosome that actually helps. And rarer still, you get an extra chromosome that not only helps, you manage to pass it on to an offspring.
BTW, about 1 in every 500 females are born with an extra Y chromosome. Most never realize it, as it usually takes a DNA test to discover. Apart from being barred from the olympics, I don't think there is any detrimental effects.Gnu Ex Machina - the Gnu in the Machine
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Rogan:
First, you need to define "free will" and establish that we actually have it.
Good luck.
As for the difference between human and chimp chromosome count: we have 23 pairs, the other great apes have 24. This was due to the fusion of two chromosomes, and the evidence for this is the fact that the telomeres at the ends of the fused chromosomes still exist in the middle of the new chromosome.
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As for the difference between human and chimp chromosome count: we have 23 pairs, the other great apes have 24. This was due to the fusion of two chromosomes, and the evidence for this is the fact that the telomeres at the ends of the fused chromosomes still exist in the middle of the new chromosome.
That is pretty neat though. I never knewGnu Ex Machina - the Gnu in the Machine
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There are plenty of transitional fossils in just the fossil record for humans from upright walking apes to modern humans with a progression occuring over ~4 million years. The interesting time frame to me is what happened during the last 300,000 years, the hominid believed to be the common predecessor of all humans over the last ~400,000 years - homo erectus - was around since 1.6-1.9 mya and remained quite static wrt evolution for more than a million years, then around 250-350,000 years ago, something happened leading to us. What makes this even more curious is that fossils of homo erectus have been found in Indonesia dated as recently as 40-60,000 years ago, living AFTER anatomically modern humans had already "evolved" in Africa.
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I do believe in evolution (don't get me wrong!) but my major worry would really be the apparent lack of diversity in life forms on Earth. There seem like quite a few, but shouldn't there be more?
For example, why do all mammals have eyes on the front/side of their faces? Wouldn't antelopes benefit from having one on the top of their head so that they could have vision when they are grazing? Predators have them on the front to give them ability to judge distances - but why not also have one behind? Also, there are plenty of creatures who mainly use hearing rather than sight, but still have two (fairly useless) eyes - why are there none with one? Does this mean that all mammals (or I suppose dinosaurs) are decended from the same 2-eyed creatures?
Hearing is another example. Why are all hearing systems basically the same? There must be thousands of ways of detecting vibrations, but only a few of them have evolved. Why?
In genetic terms (or function terms) an elephant is really not that different to a giraffe. It is not terribly long since they diverged in the genetic tree. I don't understand why there isn't a completely differently designed animal, perhaps with a genetic structure which diverged much earlier.
I suspect that there will be some reason for this found sometime - such as evolution sometimes happening in big jumps, soI am not too worried. But I am still uncomfortable with the traditional ideas.
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Hearing is another example. Why are all hearing systems basically the same? There must be thousands of ways of detecting vibrations, but only a few of them have evolved. Why?
because hearing has developed early on, and genetically, there is a very slim chance of developing an alternative hearing system, so what is usually made are upgades and modifications to existing systems. that's the rule. of course, there are exceptions.
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For example, why do all mammals have eyes on the front/side of their faces? Wouldn't antelopes benefit from having one on the top of their head so that they could have vision when they are grazing? Predators have them on the front to give them ability to judge distances - but why not also have one behind? Also, there are plenty of creatures who mainly use hearing rather than sight, but still have two (fairly useless) eyes - why are there none with one? Does this mean that all mammals (or I suppose dinosaurs) are decended from the same 2-eyed creatures?
Hearing is another example. Why are all hearing systems basically the same? There must be thousands of ways of detecting vibrations, but only a few of them have evolved. Why?
In genetic terms (or function terms) an elephant is really not that different to a giraffe. It is not terribly long since they diverged in the genetic tree. I don't understand why there isn't a completely differently designed animal, perhaps with a genetic structure which diverged much earlier.
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