The evolution of skin

[2-0-Sixx]

I originally posted this on a different thread, but I think it diserves it's own thread since there seems to be so many "race" threads.
_______________
It's interesting to note that blonde hair is "endangered" and will be extinct by 2202.

Skin evolution is relatively new to humans. Skin color is mainly based on a combination of how much ultraviolet light humans were subjected to and certain vitamins.

If only some of you would have listened in Science class!

"Jablonski and Chaplin predicted the skin colors of indigenous people across the globe based on how much ultraviolet light different areas receive. Graphic by Matt Zang, adapted from the data of N. Jablonski and G. Chaplin"

People in the tropics have developed dark skin to block out the sun and protect their body's folate reserves. People far from the equator have developed fair skin to drink in the sun and produce adequate amounts of vitamin D during the long winter months.

It isn't rocket science people.

I never understood race issues. Skin color has absolutely nothing to do with the way people think. Take a dark skinned man and raise him in a certain environment and guess what? He will be just like a light skinned man raised in the exact same environment.


You can go to http://www.pg.com/science/skincare/Skin_tws_22.htm and learn about how skin color has changed over thousands of years, and how it will continue to change.

 

[shep]

good post man

 

[2-0-Sixx]

http://www.bgsu.edu/departments/chem/faculty/leontis/chem447/PDF_files/Jablonski_skin_color_2000.pdf ---pdf file that breaks down the science.



http://www.pbs.org/wgbh/evolution/library/07/3/text_pop/l_073_04.html
"Until the 1980s, researchers could only estimate how much ultraviolet radiation reaches Earth's surface. But in 1978, NASA launched the Total Ozone Mapping Spectrometer. Three years ago, Jablonski and Chaplin took the spectrometer's global ultraviolet measurements and compared them with published data on skin color in indigenous populations from more than 50 countries. To their delight, there was an unmistakable correlation: The weaker the ultraviolet light, the fairer the skin. Jablonski went on to show that people living above 50 degrees latitude have the highest risk of vitamin D deficiency. "This was one of the last barriers in the history of human settlement," Jablonski says. "Only after humans learned fishing, and therefore had access to food rich in vitamin D, could they settle these regions."

 

[2-0-Sixx]

In case some of you don't feel like clicking on the PBS link in the first post,

" Similarly, in the last few hundred years peoples with white skins have migrated to Australia and South Africa - areas of high sunshine to which their skins are not well adapted, and among them sun damage and skin cancer rates are high.
Some skin types appear to show specific and curious adaptations to their climate. Many Scandinavian people have pale skins and light hair in winter. In the short but sunny summer, many of them tan quite markedly and quickly while their hair bleaches to almost white.
In the last few centuries, increasing ease of travel and the creation of multinational countries such as the USA have led to a wide range of different shades of skin and hair types and colors among the world's population."

 

[2-0-Sixx]

"These beautiful Caucasian children (brother and sister) come from the original Indo-Aryan stock,
whose descendants have populated a region stretching from western
Europe to the Indian subcontinent."

 

[WHITE DEVIL]

Sick.

This post was fuckin tight.

 

[2-0-Sixx]

Functions of the epidermis

The epidermis has three principal functions:

-protecting the body from the environment, particularly the sun
-preventing excessive water loss from the body
-protecting the body from infection.


-protecting the body from the environment
Unfortunately the sun also produces less beneficial rays, which are completely invisible to us, called ultraviolet radiation. (Sun beds also expose their users to these rays.) Part of this radiation is reflected by the stratum corneum at the skin surface, part is absorbed by the melanin in the epidermal cells, and some is scattered within the skin. All three processes contribute to the vital function of protecting the nuclei of the cells in the epidermis and the collagen of the dermis.
This scattered radiation creates a lot of high-energy particles, which are called free radicals. Free radicals are very reactive, and attack the constituents of the skin: this is why over a long time ultraviolet radiation produces so much damage. This will be discussed in Chapter 4 ('Skin and aging').

-preventing excessive water loss from the body
Throughout our lives our bodies naturally lose water by constant gentle evaporation through our skins (transepidermal water loss, TEWL), although we are unaware of the process. Preventing excessive water loss is exceptionally important in itself - both to the skin itself and to the body as a whole. In the normal epidermis the water content gets less the closer we get to the surface. Water makes up to 70-75% of the weight of the basal layer, but only 10-15% of the stratum corneum.
The stratum corneum is a particularly important barrier to the control of moisture loss.

It is also a highly effective barrier against the outside environment, being tough but flexible provided it is well hydrated. If its water content falls below 10% it becomes dry, less flexible and increasingly prone to damage, breakdown and infection.
The epidermis as a whole is about 35 micrometres thick when dry, but can swell to 48 micrometres on full hydration. This depends more on the humidity and temperature of the surrounding air than on how much we have drunk!

-protecting the body from infection.
The natural layer of oil-in-water emulsion on the skin is the first barrier against invasion by micro-organisms such as bacteria, fungi and yeasts. The stratum corneum provides the next level of defence.
White blood cells in the skin can capture and destroy bacteria invading the epidermis. As a result pus may form.
The epidermis also contains special defence cells (Langerhans cells) which are spread out amongst the keratinocytes. These cells mop up invading foreign substances that have found their way into the body, and take them off to special white cells (lymphocytes) in the lymph glands. Here they are neutralised.

An important element of defence concerns chemicals. If a chemical such as nickel is constantly absorbed through the skin, say from a button on one's jeans, it is first taken up by the Langerhans cells; later, however, special lymphocytes called T-cells make antibodies to that chemical. This can in time lead to an allergic skin reaction at the site of the button as the T-cells rush to meet the invading chemical. Allergies are discussed further in Chapter 9 ('The safety of cosmetic products').

Read the rest, here http://www.pg.com/science/skincare/Skin_tws_40.htm

 

[Ironic Commando]

now pay attention bitches!!!!!!! fuck what ya racist moronic family has to say...many of which dont even have a GED..and many of you still take more stock into hillbilly bullshit then biology and other science. be ashamed of yourself

 

[Ethereal]

2-0-Sixx: In your expert opinion, with light of what you just posted, would you say that it is, or is not possible to link a color of skin to be a curse of humanity? Seeing that you believe color of skin to cause no seperation in ones thinking, I must ask because of your absence in the before mentioned thread. I know it's hard for you to agree with me on something, but when people come in this thread claiming "it's fucking tight" yet argued me word for word on why I think skin color is not linked to the will to cause destruction, it's becomes a little confusing.

By the way, great thread. I hope everyone who posted in the "humanitys curse" thread reads through this.

 

[2-0-Sixx]

I’m sure we agree on more things then we would both admit.

I am absent from many “race” threads because I choose to be. I get extremely frustrated with people’s ignorance, so I ignore the threads entirely.

There is absolutely no such thing as one certain race being a curse to humanity. It’s ridiculous. If we look back throughout history, we will see all “races” committing horrible crimes and we will also see all “races” doing wonderful things.

As I said before, if you take a dark man, put him in the exact same conditions as a light man, they will be similar. If you take one group, or one race, split them in two groups and separate them on Mars, one group living in the north the other in the south, isolated from each other, they will be completely different.

 

[559_Soldado]

http://www.bgsu.edu/departments/chem/faculty/leontis/chem447/PDF_files/Jablonski_skin_color_2000.pdf ---pdf file that breaks down the science.

great find. I learned alot of facts from there

 

[Ethereal]

^^

 

[I. Cold]

interesting

 

[I AM]

Real interesting thread...

 

[askG]

everybody links color of skin with race...so africans are darker because theyre right under the sun, so what, theyre still black, so whites in the US are white because they dont have much sun on top of them, theyre still white...would you rather i have named that other thread "are americans from european descent living in the US humanitys curse"?...lol, come on...we all associate color w race, wether its scientific or not, its there, just like you wold think that the slanted eyed ninja standing in front of you is chinese, its a characteristic that fits that person.

 

[m.w.merlino]

skin color really has nothing to do with the mind, it has to do with cultrue and the percieved notion of traits given to people who have a certain skin color.

 

[WHITE DEVIL]

No, white skin makes you a businessman, and black skin makes you a hip-hopping, thugged-out basketball player

 

[askG]

^^
where does that leave wacko jacko?

 

[Ethereal]

would you rather i have named that other thread "are americans from european descent living in the US humanitys curse"?...lol, come on...

Well what is it that your trying to say. If you're saying that people with "white" skin are a curse (which you implied) then your thread should remain unchanged and in gross error. But if you were talking about those "white" people who decended from Europe, then yes, you should have said Europeans, or those decending from there, it's not that difficult.

just like you wold think that the slanted eyed ninja standing in front of you is chinese, its a characteristic that fits that person.

No, I would think he was Asian.

skin color really has nothing to do with the mind, it has to do with cultrue and the percieved notion of traits given to people who have a certain skin color.

My thoughts exactly.

 

[WHITE DEVIL]

Jacko is an alien.