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Author Topic:   Sexual Selection, Stasis, Runaway Selection, Dimorphism, & Human Evolution
New Cat's Eye
Inactive Member


Message 56 of 131 (211951)
05-27-2005 5:51 PM
Reply to: Message 54 by RAZD
05-27-2005 7:51 AM


Re: for Catholic Scientist
So, the sweat glands evolved as the hair became thinner? Do you suppose that they are connected? Perhaps some transitional apes existed that had thinner hair and eccrine glands that produced more than just pheromones. Maybe it was a very gradual thinning of the hair rather than a mutational leap to hairlessness. When I saw that hairless chimp at the zoo it made me think it was possible that a genetic mutaion could jump right from hairy to hairless, and possibly change that trait of the species if the mutation stuck.

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 Message 54 by RAZD, posted 05-27-2005 7:51 AM RAZD has replied

Replies to this message:
 Message 57 by RAZD, posted 05-27-2005 11:53 PM New Cat's Eye has replied

  
New Cat's Eye
Inactive Member


Message 58 of 131 (212046)
05-28-2005 12:43 AM
Reply to: Message 57 by RAZD
05-27-2005 11:53 PM


Re: for Catholic Scientist
I'm sure I get what your saying. A jump from hairy to hariless would most probably not work, because it isn't likely to be survived through the environmental changes that would be expected. And, it seems that the amount of hair a species has isn't portrayed through their fossilized record, so, perhaps we will never know.
One thing I would like to point out is:
This makes a sudden change (by mutation or{medical\environmental} aberration) to a {thin\short} hair condition highly unlikely to survive long enough to breed a second generation without intervention of some kind.
bold added for emphasis
but, a lot of the evolutionary advances that I've learned about seem highly unlikely, so perhaps we can't rule this possibility out all toghether. I understand what you are saying though, and it seems that a gradual change is much more probable.

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New Cat's Eye
Inactive Member


(1)
Message 90 of 131 (710288)
11-04-2013 10:35 AM
Reply to: Message 88 by WJK
11-04-2013 6:37 AM


Re: For WJK (How Evolution changed humans’ appearance )
Could you expand on "runaway". The meaning escapes me!!!!
That's when sexual selection causes the species to evolve a trait that otherwise is not useful for survival. The poster-child is the Peacock's tail. It doesn't aid them in survival, and in fact it is actually costly for them to produce, but since the chicks dig it, the sexual selective pressure makes it happen anyways.
Here's a link:
Page not found

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