Re: Head Hair Is Not Fur Re: selection criteria for obesity
From: firstjois (firstjoisyike_at_hotmail.com)
Date: 01/01/05
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Date: Fri, 31 Dec 2004 23:56:24 -0500
Rich Travsky wrote:
>> firstjois wrote:
>>>
>>> Andrew Glasgow wrote:
>>>>> Paul Crowley wrote:
>>>>>
>>>>>
>>>>> <You can't handle the snip!>
>>>>>
>>>>>
>>>>>> Not so. Fur is _worse_than_useless_
>>>>>> when it regularly gets wet and has to
>>>>>> dry in air. It will drain massive amounts
>>>>>> of energy from the animal under such
>>>>>> conditions, and not be an insulator at
>>>>>> all. Persistent showers of rain (in the
>>>>>> rainy season) cause distress to most
>>>>>> animals in Africa, including chimps.
>>>>> So why do animals have fur in areas where it rains constantly,
>>>>> then?
>>>
>>> My guess is that none of you have long hair. I do and I can't be
>>> bothered with a hair dryer but it doesn't matter, even wet hair is
>>> insulating - even if I'm out side most of the day and my hair is
>>> still wet when I get home, my head will still be warm. Hair
>>> insulates. Hair is fur.
>>
>> Look what just popped up.
>>
>> http://mednews.wustl.edu/tips/page/normal/4405.html
>> Don't call it fur!
>> After combing the scientific literature, researchers conclude head
>> hair and fur aren't the same
>>
>>
>> Dec. 27, 2004 - Mammals have fur over most of their bodies, but at
>> some point during evolution, we humans lost that fur covering.
>> Researchers at Washington University School of Medicine in St.
>> Louis argue that hair on the head is somehow different from fur
>> because fur stops growing when it reaches a certain length, but our
>> head hair continues to grow. To drive home their argument, they ask
>> in a recent article in the journal Evolutionary Anthropology, "Have
>> you ever seen a chimpanzee getting a haircut?"
>>
>> When Arthur H. Neufeld, Ph.D., the Bernard Becker Professor of
>> Ophthalmology and Visual Sciences at Washington University School of
>> Medicine in St. Louis, first put forth his idea that human head
>> hair is somehow different from fur, over dinner with his close
>> friend and colleague Glenn C. Conroy, Ph.D., professor of anatomy
>> and anthropology, Conroy told him he wasn't aware of anyone in
>> anthropology studying differences between hair and fur.
>>
>> "So we talked about it for a while and asked questions like why does
>> human head hair continue to grow? Where did this difference arise
>> in the evolutionary process?" Neufeld recalls. "And the more we
>> looked at it, the more we found that there really isn't anything in
>> the literature."
>>
>> One reason might be that under a microscope a hair follicle taken
>> from the leg would look just about the same as one from the head.
>> Our human "fur" if you will - the hair under the arms, on the legs
>> and elsewhere - is anatomically identical to head hair.
>>
>> [ discussion of follicles and growth cycles hair transplants etc ]
>>
>> Neufeld and Conroy hypothesize that although the hair follicle
>> itself might be the same, the hair follicle growth cycle must be
>> regulated differently on the head than elsewhere on the body.
>> ...
>> There is a slight difference in the levels of keratin in human hair.
>> [...] The keratin content of human head hair is different than
>> what's found in fur on chimpanzees and gorillas, our closest
>> biological relatives.
>>
>> A potential reason for that difference is a segment of human DNA
>> called a pseudogene. The actual gene, known as ?hHaA, makes a
>> keratin protein in chimps and gorillas. Although the same DNA
>> sequence is preserved in humans, human cells don't use it to make
>> the protein. That's why scientists call it a pseudogene.
>>
>> "I don't have any sense that this necessarily is a clue," Neufeld
>> says. "It's just the only article I was able to find in the
>> literature that distinguished human hair from chimpanzee or gorilla
>> hair, in terms of molecular biology and biochemical makeup."
>> ...
>> But even if it's possible to identify the factors that make head
>> hair grow differently than body hair, scientists may never know why
>> humans evolved head hair that's so different from our closest
>> animal cousins.
>>
>> "If I had to guess, I would think a lot of this somehow has to do
>> with sexual selection," Conroy says. "But how continuously growing
>> hair plays into sexual selection is anybody's guess."
>> ...
LOL! But you can see in doggies that changing from one kind of hair/fur to
another must be a piece of cake. My Sheltie's coat is just about 100%
different from the Poodle's and the Poodle's body hair grows very like our
head hair. And both doggies like cake.
Jois
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