Re: [HAPS-L] Skin--never leave home without it!

[Terry Meehan <tjmeehan333@xxxxxxxxx>]

Why skin is dark to light:  UV exposure; lower UV results in selection for
lighter skin so enough UV reaches the cells to make vitamin D & vit D is
needed for.... [ Over the last couple of decades anthropologists have made
a good case with lots of evidence for skin darkness being dependent on
latitude, adjusting for env. where there's lots of UV/glare despite
latitude (snow, ice, sea, high altitude), and of course, recent migrations
mixing it all up (at least the last several thousand years). ]

Why are skin is "naked."  Typical human skin has the same density of hairs
as a chimp (our living sister species), but our pelage is finer & shorter.
 Major hair reduction can almost for sure be predicted to have occurred at
the onset of the genus Homo (2.4 mya), when the brain greatly
enlarged--nervous tissue is very heat sensitive, and we need to cool our
fat head; humans pay a great price for such an elaborate cooling
system--in salt & water.  [ It would be nice if human kidneys were much
better at conserving water. #@!$$ ]  As we sweated more to cool a bigger &
bigger brain, can't have insulating hair--it hinders evaporative
cooling--imagine trying to sweat through mom's fur coat.  Concomitantly
our hyopdermis is unusually thick all over--odd for a terrestrial
mammal--it's compensating insulation for loss of fur coat.  [ I never
thought the "aquatic" ape hypothesis held any water. ] 

There are other neato things about human skin, including communicative,
sexual, & paedomorphic traits, but it's now dinner time, and then a shave
to look younger & sexier.  Although, for me, by this decade, I think it's
too late for that...@#!$$%% Terry 

PS   You could also go medical--things done to heal it, etc. to show its
importance or even the purely cosmetic stuff.  

Here's my 201 skin ad: 
Few organs are as accessible, large, varied in function, & as
underappreciated. Your integument accounts for about 7% of your total body
weight (11lbs for a 155lb person), making it the largest organ of the body
(the liver comes in 2nd).  It?s about 20 square feet in surface area and
varies in thickness from 0.2mm-5mm.  It?s continuously abused, abraded,
attacked by microorganisms, irradiated by sunlight, & exposed to
chemicals.  On average, one sheds 30lbs of epidermis in a lifetime and you
get a new ?coat? every 35-45 days.  Of all the systems, the integument is
the only one you see every day.  It?s more comfortable & durable than Lt.
Columbo?s trench coat.  The integument is highly water resistant,
stretchable, washable, perma-press, self-repairable, lasts a ?lifetime,?
and its natural hair & tone colors always match, and for the more
fashionably conscious, matches your clothes too.

Why I could talk about human skin adaptations all night...but I am a
diurnal primate...ha ha...



--- Teri Trendler <tatrendler@xxxxxxxxxxxx> wrote:

> Hi all!
> 
> How appropriate that as we draw near to Sunny "Sandy Eggo" I have a 
> school wide "theme" that will be on display there and I'd like your 
> creative help with.
> 
> "The Pasadena Arts Council is pleased to announce the organization of 
> Art & Ideas, a festival of the arts, sciences, and humanities in 
> Pasadena and surrounding communities.  The theme for Art & Ideas '07 is 
> "Skin".
> 
> So as an A&P faculty member I've been asked what my division would 
> offer for the above topic.  My reply was if we want to really get 
> "kids" interested we talk about piercings and tattoos...even have them 
> demo'd.  What I'm wondering is do any of you have ideas I can steal? 
> lol  I'd love to show those close-ups of the "bugs" that live on us for 
> shock value but what else?
> 
> Thanks!
> Teri
>   
> 
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tjmeehan333@xxxxxxxxx    412-606-3996
Chatham College  Buhl Hall           
Woodland Rd
Pittsburgh  PA  15232-9987

Bucky: I'm not gonna say Satchel is stupid...but that's only because I can no longer hear his voice over the dueling banjos.  
 - Get Fuzzy by Darby Conley



 
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