The Evolution of Skin Colour
1. What are the causes of skin cancer?
Exposure to abnormally high frequencies of light can potentially alter the DNA of a cell and turn it cancerous, the resulting cancerous cells are known as skin cancer. The most common cause is ultraviolet light emitted by the sun although it has been known to be caused by tanning booths, unusually high levels of x-rays, exposure to some chemicals and in rare cases the abnormal genes that cause skin cancer can be inherited by children from their parents.
2. Why are Caucasians more at risk of skin cancer than other populations?
Melanin is the pigment in the skin that absorbs ultraviolet light and protects the skin from sun damage, so the less pigment in a person’s skin the less protection they have from ultraviolet light. So light skinned people (Caucasians), particularly those with light coloured eyes and light coloured hair are more susceptible to sun damage and skin cancer than people with more pigment in their skin. People, who have no melanin at all, like people with albinism or vitiligo, are much more susceptible to skin cancer.
3. At what age does skin cancer typically occur? Is the incidence of skin cancer greater in youth or old age?
A person's lifetime sun exposure is a known factor in skin cancer because of this the risk of developing skin cancer increases with age, most diagnoses are made in people over 50 years of age. However people who are exposed to large quantities of ultraviolet radiation can develop skin cancer as early as 20 to 30 years of age. The average age of skin cancer diagnosis occurs at 53 years old.
4. Does the amount of UV light reaching the Earth vary in a predictable manner? If so, describe the pattern you observe.
The earth’s axis is slightly tilted relative to its orbit, this means that during stages of the earth’s orbit one side of the earth is closer to the sun than the other and becomes exposed to higher levels of ultraviolet light. Half a year later when the earth is on the
Exposure to abnormally high frequencies of light can potentially alter the DNA of a cell and turn it cancerous, the resulting cancerous cells are known as skin cancer. The most common cause is ultraviolet light emitted by the sun although it has been known to be caused by tanning booths, unusually high levels of x-rays, exposure to some chemicals and in rare cases the abnormal genes that cause skin cancer can be inherited by children from their parents.
2. Why are Caucasians more at risk of skin cancer than other populations?
Melanin is the pigment in the skin that absorbs ultraviolet light and protects the skin from sun damage, so the less pigment in a person’s skin the less protection they have from ultraviolet light. So light skinned people (Caucasians), particularly those with light coloured eyes and light coloured hair are more susceptible to sun damage and skin cancer than people with more pigment in their skin. People, who have no melanin at all, like people with albinism or vitiligo, are much more susceptible to skin cancer.
3. At what age does skin cancer typically occur? Is the incidence of skin cancer greater in youth or old age?
A person's lifetime sun exposure is a known factor in skin cancer because of this the risk of developing skin cancer increases with age, most diagnoses are made in people over 50 years of age. However people who are exposed to large quantities of ultraviolet radiation can develop skin cancer as early as 20 to 30 years of age. The average age of skin cancer diagnosis occurs at 53 years old.
4. Does the amount of UV light reaching the Earth vary in a predictable manner? If so, describe the pattern you observe.
The earth’s axis is slightly tilted relative to its orbit, this means that during stages of the earth’s orbit one side of the earth is closer to the sun than the other and becomes exposed to higher levels of ultraviolet light. Half a year later when the earth is on the