Name: 為什麼我們有不同的膚色？| 奧琛時間 (Why do we have different skin colors? | It's AumSum Time)
Uploaded: 2021-01-14T07:47:42.000Z
Duration: 1 min 10 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

It is because of a pigment called melanin
and ultraviolet radiation of the sun.

Millions of years ago, people living near equator received a lot of sunlight and ultraviolet radiation.

Now, ultraviolet radiation is actually absorbed by our skin to produce Vitamin D.

But excess radiation can damage our skin cells.

Hence, the skin of these people produced more melanin to block the excess ultraviolet radiation.

These people and their succeeding generations adapted to have a higher level of melanin in their skin.

However, people living away from equator received less sunlight and less ultraviolet radiation.

Hence, in order to absorb sufficient ultraviolet radiation and produce the essential Vitamin D.

These people and their following generations adapted to have a lower level of melanin.