Skin Cancer in Canada Although it is not possible to gather data on skin cancer

Question

Skin Cancer in Canada Although it is not possible to gather data on skin cancer in early hominins, modern data on skin cancer provide some helpful information. There are 2 main types of skin cancer. In most cases, non-melanoma progresses slowly and doesn’t spread to other parts of the body. According to the Canadian Cancer Society, in 2009, 75,100 Canadians were diagnosed with non-melanoma skin cancer, but only 270 people died of this disease. The median age of diagnosis for non-melanoma skin cancer is 60. In contrast, melanoma skin cancer can be fatal if it’s not treated early on. However, according to the Canadian Cancer Society, only 5,000 new cases of malignant melanoma were diagnosed in 2009. Of these, 940 people died. Although it can strike at different ages, the median age of diagnosis of malignant melanoma is 59. Skin cancer risk increases with UV light exposure, and light skinned Caucasians have a higher incidence of skin cancer than other ethnic groups in Canada. Evolution of Skin Color – The Alternative Explanation 3.

In recent years, many people have challenged the conventional view that skin cancer risk alone explains global patterns in the distribution of human skin color. Use the data on skin cancer in Canada to explain why risk of skin cancer might not be a sufficient explanation for the distribution of skin color in indigenous populations.

Explanation / Answer

Fitness refers to the ability of an organism with a certain set of genes to successfully reproduce before it dies off. Differences in fitness are one of the ways in which frequencies of genes can change, giving rise to phenotypic variation. Caucasians have the lowest amount of melanin in their skin cells when being compared to other cultures. Melanin is crucial to protecting our skin from UV rays, and so someone with a darker skin tone is better protected. The more naturally light people would be found in the far north or far south, the more naturally dark people would be found closer to the equator. This is of course assuming they are not a mix of multiple races. Well, people of darker skin tones are producing more melanin in their bodies, which is critically important in countries with high UV exposure. Those in the more northern/southern areas of the earth would have no use for such a high content, and so have a fainter pigmentation.

We have evolved to have different skin tones based on our ancestral origin. Different descents will have various skin tones based on where in the world they are located. Those with fair skin in an area close to the equator would have suffered from the strong UV rays, and their rates to develop skin cancer would have been much higher. We can darken and lighten to a degree, but extreme climate change would call for more dramatic affects. Skin cancer can exert a lot on reproductive success, especially around ages 20-30, when skin cancer is more predominant, because that they time that people are usually getting married and having children. The effect on the blood folate levels were that the exposed group had lower levels of folate left in the blood. The effect on the folate concentration was that the exposed group again had lower levels then the non-exposed group. Folate deficiencies during pregnancy can cause malformations in the nervous system and the gastrointestinal system.

It can also cause miscarriages and because folic acid is important in embryonic neural tube formation, natural selection favored people with dark pigmentation because they could produce healthy offspring. A light skin tone would be expected to be correlated with higher levels of folate because the darker you are, the UV rays deplete the folate levels. . Light skinned people living in the tropics have a very low percent of reproductive success because the people who are dark skinned living there would probably be attracted to the same skin tone. Light skinned people living in the polar region would have a high percent of reproductive success because the people living there are not very dark and would be about the same skin tone as the light skinned person. Vitamin D is linked to natural selection because natural selection includes having characteristics that make them better adapted to their environment to survive.

Vitamin D is used to maintain a healthy heart, stable nervous system and an effective immune system, all of which can help organisms adapt to other places needed for survival and to reproduce. The skin tone that allows someone to maintain a recommended level of Vitamin D would be a darker skin tone. This is because lighter skin allows deeper penetration by UV rays. The evolution of the variation and distribution of human skin color depends on where you live. People living close to the equator will have darker skin then people living in Alaska. It varies in different places around the world because as people moved to farther areas from the equator with lower UV levels, natural selection favors lighter skin which allowed UV rays to penetrate the skin and produce more vitamin D. Various skin color groups are no longer living in the areas that their skins were adapted to. This combined with the trend for people to stay indoors, use sunscreens and get less sun exposure has meant that various skin color groups have to take various actions to reduce the risks of health problems arising from sun exposure and their skin color. Social relations and cultures may have a significant impact on the perception of skin color, but this is impossible to estimate. In traditional African societies, light skin was often regarded as unhealthy.

Naturally occurring albinos are ostracized. Skin color preferences may have affected reproductive success. Even today skin tone preferences varies among different culture. Many cultures historically favored lighter skin in women, and many young women always use umbrellas when they go out in the sun. While skin tanning is often most noticeable on light skinned people, dark brown skin can also tan in response to prolonged exposure to the sun. Some Europeans have lost their ability to tan. Their skin burns and peels rather than tans. This is caused by a mutation leading to the production a defective skin protein that interferes with the production of melanin. They are less suited to tropical and subtropical areas being more prone to sunburn and skin cancer. The same is true of albinos. In conclusion, like many other evolutionary changes the adaptive changes in skin color appear to have developed due to a combination of inherited mutations and natural selection for variations in skin color.

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