The human population is subject to environmental resistance. Give examples to show that the human population is not immune to environmental regulations.
2006-10-07 22:08:41 · 3 answers · asked by Joenaliza Z 1 in Environment
Here's a couple or three examples:
Skin colour. Melanin is the pigment that protects skin from damage by ultra violet rays. It also as the effect of blocking vitamin D production. In the tropics, no problem. There is enough sunshine to allow vitamin D production and the skin required protection. But in higher latitudes there is not enough sunshine to allow the body to synthesise the required levels. UV protection is not such a requirement either. Therefore individuals with a paler skin born in these areas would be favoured by natural selection.
Eye colour. Dark eye colour absorb more light. Not normally a problem but what if you are exposed to very bright reflected light, such off a snowfield. Paler eyes may be an adaptation against snow blindness.
Physical size. Ever noticed how individuals from island races tend to be smaller in stature compared to their continental neighbours? That is because there tend to be less natural resources on islands (resources being related to land area available). Therefore those individuals who could get by on less resources would survive periods of famine and pass on their genes to the next generation.
Modern technology has done away with many of these environment factors for the meantime. That does not mean it will continue to in the future.
2006-10-07 22:31:27 · answer #1 · answered by 13caesars 4 · 0⤊ 0⤋
Hurricane Katrina
HIV/AIDS
Obesity
2006-10-07 22:10:21 · answer #2 · answered by buccinator 3 · 0⤊ 0⤋
No one lives above 5000 m or under the sea.
The desert remains pretty much left undeveloped.
2006-10-07 22:17:32 · answer #3 · answered by lkraie 5 · 0⤊ 0⤋