Bridget Hoadley, of Nga Tawa School, asks :-

Annie Robinson, of Ilam School, asked:-

Why are people different colours? What makes our skin the colour it is?

Mike Green, an anthropologist at Otago University, responded.

All people have the same three pigments in their skin: carotene, a yellow pigment, is related to vitamin A; haemoglobin, a red/pink substance in the blood, contains iron to transport oxygen around our bodies; and melanin, a dark pigment, protects us from the damaging effects of ultraviolet (UV) rays in sunlight.

Melanin itself varies in colour from yellow through to black. People with different skin colours simply have different amounts of melanin in their skin, so that dark skinned people have lots of melanin.

One of the neat things about melanin is that depending on how much sunlight is around, our skin can either increase or decrease the amount of melanin it needs. This is because sunlight contains UV rays, which can cause skin cancer, and our bodies want to control the level of UV light reaching it and keep it at a safe level. As the amount of UV light increases, say during the summer, our skin responds by increasing the amount of melanin and hey presto! - we end up with a suntan. But the skin can produce only so much melanin - if you start off light-skinned, you will only tan a small amount and will still be open to possible skin cancers. Remember the sun screen!

You can understand now why it would be advantageous for people living in hot, tropical climates to have dark skin.

Skin colour has absolutely nothing to do with culture or intelligence - it is simply inherited from our parents.