Trait changes in a species.

To get back to the original topic issue the question of fixing traits:First the relation to human "hairlessness" -- this is not similar to the "hairless chimp" because the trait that has been fixed in humans is the type of hair (more vellus and less terminal) and less {length\diameter} of the hairs, and not in the number of hairs.Note that terminal hairs normally replace vellus hairs during growth, so the retention of vellus hairs is more like neoteny than a mutation trait. This can actually work more readily for changing the way a feature is expressed than in {creating\eliminating} a feature: there is natural variation in any feature of a species, and if one {side\version\type} is more favorable to {survival\breeding} then it will increase in a population (the alleles frequency issue), and over time there can be a definite trend in one direction or another.There are many examples of this in action. The finches on the galapagos are another example, where one species developed thicker beaks during a period of drought on one island, but then regressed back to previous beak size when the drought ended.Given enough time such divergence can develope quite different appearances between members of isolated species, and when the point is that they no longer recognize the other population as breeding mates then speciation has occured.We see examples of this as well, with the asian greenish warblers being probably the best example. This is a "ring species" with several varieties that do interbreed in areas of overlap except at the closing of the ring: the two varieties there behave like different species and ignore each other as both potential mates and as competitors for mates.Enjoy.

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we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

Why would we do that? Sexual selection has obviously selected for more cranial hair in humans. I don't see how that would be an appropriate sample. "Less" is ambiguous, sure; "hair" vs. "hairs" is not, at least to me.

Well congratulations, you just threw out the validity of the whole comparison.Sexual selection has obviously selected for more youthful, less terminal hair in favour of continued vellus hair, and thus more apparently bare females: especially in the chest and buttocks areas. This is a classic run-away sexual selection pattern, that runs until it can no longer affect the population without adverse effect, while still showing continued preference for further development.This has also resulted is similar but less extensive more variable expression of this tendency in males.If you want to discuss this particular aspect further, this is the topic of the thread {Sexual Selection, Stasis, Runaway Selection, Dimorphism, & Human Evolution} at:http://EvC Forum: Sexual Selection, Stasis, Runaway Selection, Dimorphism, & Human Evolution{{(abe) And I would love to have your input and point of view on that topic anyway oh? I could also say "Less" is ambiguous, sure; "hairy" vs. "hair" is not, at least to me. (eoe)}}Then we can get back to fixing traits changes in species ... aka the original topic of this thread ... of which "hairlessness" was but an example (and possibly a poor one for a number of reasons, not least of which is that the "hairless chimp" is not a trait but a medical condition). k?This message has been edited by RAZD, 05*29*2005 10:20 AMThis message has been edited by RAZD, 05*29*2005 10:27 AM

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we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

If you say so. It was never my comparison to begin with but it still seems perfectly adequate to me. Works for me. Get back to whatever you like. I don't for the life of me know what it is we're arguing about.

agreed