Skin Color: An Adaptation And Inheritance Condition.

Skin color: an adaptation and inheritance condition.
The world isn’t static; it maintains itself in constant evolution. Years ago, the scientific though that the age of the earth was about 5,570 years, but now it’s known that the real age of the earth is about 4.5 billion years. The scientists understood that the earth experiment the necessity of various changes through time. They realized thatthe earth has been going through a process of constant of evolution and that it was impossible that it could be so young.
As Charles Darwin proposed, the process of evolution is gradual and continuous. We have for example, the evolution of the bird’s wings or the lounges of the vertebrates. This evolution is produced through the Natural Selection, which works in two phases: The production ofvariability and selecting between those variables what is need for survivor.
Every specie have some different characteristics with others organism of the same species. In humans, for example, there is a mechanism of human adaptation. This mechanism creates differences between the species around the world. A person that lives in the west side of the world has characteristics which are verydifferent to the people on the east side. This is because humans adapt to the environment that the earth shows. One of those characteristics that strongly vary according to the environment is the skin color.
All the genes of the skin color are a lot alike, but there are differences that make some skin different in color than another. In Africa, and other hot places in the world there is a tendency ofpeople with black skin color, in the other hand, in countries at the north of the earth where the sunlight is weaker and the weather is cold, the tendency is to find populations with a majority of white skin color. In other places such as Central and South America most of the people has a brown skin color, but that’s because other certain conditions, because America’s population used to be mostlyred skin.
The skin color of each person is determined mostly because the inheritance. This is because the presence of two types of pigments: the melanin and the hemoglobin (Nina and Chaplin 2000). The melanin is responsible for the black skin color, which is produced by cells called melanocytes. Through a melanogenesis process, the melanin is created and forms two types of melanin: eumelanin,which is a pigment black or brown, and the pheomelanin which is a pigment red or yellow. Inside of this cells there is melanin accumulated in some small’s organs called melanonsomes (Nina et al 2000).
The difference between the skin colors of people depends on the number, position, and size of the melanonsomes inside the melanocytes. Everything is genetically calculated, it becomes determinate byour inheritance. But the quantity of melanin that is formed in the skin depends mostly on the sun. The melanin works as a sunscreen; it means that it reflects the sun light preventing damages to our skin. It protects the skin from the sun light. The creation of melanin is, therefore, the defense of the skin. That is the explanation of the evolution of the skin adaptation to the environment.
InAfrica, which is the place where the population is mostly black people, the sunlight is very strong. This is a reaction of the skin to the environment, it creates more melanin according to what is needed and as a consequence of the abundant melanin the skin is black. The evolution which the skin go through in order to defend itself from the environment is what was mentioned before as humanadaptation. The other condition, which is white skin color, becomes because the lack of necessity of an abundant presence of melanins. Since the sunlight doesn’t heat too directly the countries of the north, such as United States, Canada, Europe, and Russia, the production of melanin in the skin is less, and as a consequence the skin is white. The other pigment that gives color to the skin is the...