In this essay I will discuss the adaptations on human evolution, this includes skin color, disease, Lactase Persistence, and the negative effects of the Neolithic Revolution. I will focus mostly on the diseased portion the most because this plays a vital role in natural selection. Natural selection is the process whereby organisms better adapted to their environment tend to survive and produce more offspring (dictionary. com). Without disease natural selection would play less of a part in how species evolve.
Skin color is important in surviving when most feel like it is because we are different, when in reality we are 99. percent identical (Human family tree). I will compare the negative and positive effects of the Neolithic revolution all while explaining the lactase persistence and how it differs from lactose intolerance. Disease Microbes are the germs in which live off our bodies and make humans sick, whether to the point where we die or pass the germ to someone else. These microbes help with natural selection, and the process at which we evolve. Most often than not the disease is spread by contaminated water, not cooking the meat all the way or being bitten by an animal that has the disease that you caught.
However, in rare cases like the arrow of disease the man had had sexual intercourse with the sheep and had gotten sick (diamond, 1992). Humans are more at risk if they own domesticated animals like cows and pigs they already have diseases in them and by owning them we are at risk of catching that diseases soon or later some of these include, cat scratch fever from cats, leptospirosis from dogs, psittacosis from chickens and parrots, and brucellosis from cattle (Diamond 1992).
Zoonotic disease causes no signs of illness in its natural ost like cattle, but in humans, it has a relatively low infectious dose and may result in hemorrhagic colitis and hemolytic uremic syndrome (Greger, 2007). Skin color Melanin protects our skin from UV radiation. The skin, prevents the damage caused by ultraviolet rays, however, Genes control skin pigmentation they are among the most strongly studied by natural selection because of the skin’s role in regulating UV penetration into the body (Jablonski, Chaplin, 2012, pg. 785). The earliest humans had dark skin, it transformed from light to dark to help protect from UV radiation.
Human skin adapted to the earth’s temperature and UV radiation. High levels of melanin protected our ancestors from skin cancer (Jablonski, 2012). Light skin evolved in areas with low UV radiation to increase ability to produce vitamin D in areas with reduced exposure to UV radiation. People living near the equator are the most likely to have dark skin. Negative effects of Neolithic revolution Neolithic revolution is a period in human history marked by the introduction of agriculture and a shift from food gathering to food producing.
Humans began to cultivate crops and domesticate certain animals. This is the time when men and women began to separate into hunting and gathering, although this occurred men still controlled their society. There was positive effects of the Neolithic revolution in the use of agriculture allowed humans to develop permanent settlements, social classes, and new technologies. Even if there were positive effects there were negatives to this revolution examples of these were warfare, crop failure, and disease.
By domesticating animals it caused disease, also their crops failed because of rainfall or they did not have the necessary tools to farm. Lactase persistence Lactase persistence is the ability for human adults in some populations to digest fresh milk products (Lesson 15), it produces the inducible enzyme. Populations with high lactase persistence in Africa and Europe shared the common cultural variable of cattle domestication. An advantage of this is that they have more vitamin D. It is common for infants and children to digest milk.
In Africa, a majority of people are lactose intolerant, most humans lose the ability to digest lactose after weaning because of decreasing levels of the enzyme. Conclusion In this essay I explained disease and how it has evolved and has its own process in natural selection. I also focused on skin color and how depending on where you live depends on the color of your skin, and example of this is your melanin which protects against ultraviolent radiation, melanin has two forms dark and light.
If humans are closer to the equator they are more likely to have darker skin. The color of ones skin color does matter because it protects from skin cancer. I also discussed the Neolithic revolution and the positive and the negative effects that the culture and the Neanderthals had to deal with, these include disease because they were domesticating animals which have diseases. Lastly, we discussed Lactase persistence and how as you grow the enzyme is decreased because you know longer depend on milk to live.