Check out this article about a recent publication in Biology letters about the role of hairs mechano-sensory function with respect to ectoparasites. Why it's taken so long for anyone to notice that the sensory function is both real and useful - and give it genuine consideration when exploring human evolution is as much a mystery to me as them questions of how our 'hairlessness' evolved.
Why it's taken so long for anyone to notice that the sensory function is both real and useful - and give it genuine consideration when exploring human evolution is as much a mystery to me as them questions of how our 'hairlessness' evolved.
Well, perhaps it's because actual evolutionary biologists understand the Theory of Evolution where you don't. Perhaps it's because they know that a "vestige" need not be "functionless". Just like people have been pointing out since the very start of this thread.
Granny Magda @139, people here also disputed that hairs even have a sensory function. That's something nobody should even need to have pointed out! Doesn't theirs work or something?
Meanwhile Nina Jablonski in Sci-Am listed known functions of human hair but left out what is, for fine vellus hair, it's most distinct and clear function - sensory.
You will find that this article explores the idea that the mechano-sensory function of hairs probably predates it's function as thermal insulation and even predates the forms that we think of as mammals. ie it's not vestigial but may be the original function; it still has that function and it may still be continuing to be it's primary function.
I think it's a universal function and mammal hairs that have lost their sensory capability would be a rare exception. But if no-one asks the question how do we know the answer?
A bit combative aren't you? Not that it upsets me - these forum often are. I found this one an interesting debate that stimulated my thinking. And I don't claim great expertise, just an occasional ability to point out the obvious when all around me no-one appears to be noticing it.
The sensory function of body hairs ought to be obvious to everyone and I'm still very dismayed that leading scholars in this field appear not to have even acknowledged - until well after this thread began - that it has any relevance to the evolution of our misleadingly named 'hairlessness'.
There is no reason to see sensory abilities in hair as the reason for hair. The first answer should be the simple one. hair is a result of the body trying to keep warm/ by warming or drying. In our case after the fall or the flood our bodies reacted , or over reacted, to the areas of our bodies that had special episodic sweating and so grew hair to dry the areas up. It doesn't work and is today a memory of a original trigger and over sensitivity. Not remnants of a hairy ape origin.
Robert, the papers I've linked to suggest that sensory function is a fundamental function of hair and probably preceded it's function for keeping warm in mammal evolution. Temperature regulation via fur may have become very crucial for most mammals but the sensory function remains.
For something like eyelashes it's directly linked to the blinking reflex and protecting eyesight is important for most mammals. That the fine vellus hairs on my own face near to my eyes are so touch sensitive that it's all I can do to not rub or scratch when they are disturbed suggests a long and continuing evolutionary history that involves the mechano-sensory function. The paper by Dean and Siva-Jothy shows what I have suggested - a mechanism by which natural selection would favour finer, sparser body hair.
Meanwhile your 'after the biblical flood' scenario isn't an explanation that works for anything except, via a roundabout and convoluted route, to support a scientifically unsupportable position.
Its fine to have eye lashes helping the eyes or other agendas of hair helping the body to be sensitive to touch/feel. Yet hair on the bodies for all creatures is clearly from a need to keep warm/dry. One could in factr say first hair was for the great agenda of warmth and then evolved these other uses. No reason to see the sensitivity issue as first and foremost.
In any case its about presumptions and investigation. The bible starts with boundaries that one can presume for ones hypothesis(s).
We started without hair in eden and then still didn't need hair until the flood. Our bodies had the ability and did react to grow hair for a wetter world we found. I say these triggers are shown by the areas on our bodies that have unneeded hair. Our under arms hair unneeded hair because the body back in the day was over sensitive and interpretated episodic sweating as a threat and so grew hair to dry the area up. Yet it was not needed and fails to do the trick. However its a great clue as to the whole need and reply of our bodies regarding hair. its simply a attempt to dry/warm creatures up. No need for way out evolutionary ideas that can't be proved one way or another. our own remnants of unneeded are the best clue and fit biblical boundaries.