DISCUSSION OF THE CAUSES OF HUMAN SKIN COLOR VARIATIONS
The variation of human skin color is a complex phenomenon which have not yet been researched and studied conclusively. However, various researchers and academicians have given insight about the possible causes of this important trait. Different researches using people from different parts of the world, evaluation of their environments and diet and to some extent DNA analysis have given a variety of possible causes of human skin color variation. This causes are explained in details below.
1. Natural selection.
Theoretical explanation
Basically, natural selection is how groups of living things get better suited to their surroundings. With enough time natural selection can even lead to new …show more content…
He was spellbound by how many types of animals there were. And was puzzled by how they came to be (Jaffe, July 8, 2015).
In 1859 he published his now famous book called “On the Origin of Species.” In it he introduced the idea of natural selection. Natural selection explains how all the types of animals came to be.
In Darwin’s time people really didn’t have a clue about how natural selection could work. I mean, the fact that a chicken and a penguin (or even a velociraptor) are distant cousins is sort of unbelievable! But nowadays, we have a pretty good idea of how it can happen.
Like I mentioned, all living things have something called DNA, which is passed from parents to offspring. DNA is the code of life and provides instructions for genes. Each generation small changes in DNA can occasionally tweak the DNA and affect how a gene works.
If an altered gene is a lot better than the original (i.e. helps that individual survive better and have more kids), then over time it can spread through a population. This is because people with the change have more kids than people without it. After many generations, individuals with the new mutation will have replaced those with the older DNA. This is the process of natural selection, and can occur either on new mutations, or on a mutation already present in an individual in a population (HARRISON & OWEN, 1964 …show more content…
(Jablonski, Nina, Chaplin, & George, 2000) This form of sexual dimorphism is due to the requirement in human females for high amounts of calcium during pregnancy and lactation. Breastfeeding newborns, whose skeletons are growing, require high amounts of calcium intake from the mother's milk (about 4 times more than during prenatal development), (Kovacs & Christine, 2008) part of which comes from reserves in the mother's skeleton. Adequate vitamin D resources are needed to absorb calcium from the diet, and it has been shown that deficiencies of vitamin D and calcium increase the likelihood of various birth defects such as spina bifida and rickets. Natural selection has led to females with lighter skin than males in all indigenous populations because women must get enough vitamin D and calcium to support the development of fetus and nursing infant and to maintain their own health (Jablonski & Nina, Living Color,
The variation of human skin color is a complex phenomenon which have not yet been researched and studied conclusively. However, various researchers and academicians have given insight about the possible causes of this important trait. Different researches using people from different parts of the world, evaluation of their environments and diet and to some extent DNA analysis have given a variety of possible causes of human skin color variation. This causes are explained in details below.
1. Natural selection.
Theoretical explanation
Basically, natural selection is how groups of living things get better suited to their surroundings. With enough time natural selection can even lead to new …show more content…
He was spellbound by how many types of animals there were. And was puzzled by how they came to be (Jaffe, July 8, 2015).
In 1859 he published his now famous book called “On the Origin of Species.” In it he introduced the idea of natural selection. Natural selection explains how all the types of animals came to be.
In Darwin’s time people really didn’t have a clue about how natural selection could work. I mean, the fact that a chicken and a penguin (or even a velociraptor) are distant cousins is sort of unbelievable! But nowadays, we have a pretty good idea of how it can happen.
Like I mentioned, all living things have something called DNA, which is passed from parents to offspring. DNA is the code of life and provides instructions for genes. Each generation small changes in DNA can occasionally tweak the DNA and affect how a gene works.
If an altered gene is a lot better than the original (i.e. helps that individual survive better and have more kids), then over time it can spread through a population. This is because people with the change have more kids than people without it. After many generations, individuals with the new mutation will have replaced those with the older DNA. This is the process of natural selection, and can occur either on new mutations, or on a mutation already present in an individual in a population (HARRISON & OWEN, 1964 …show more content…
(Jablonski, Nina, Chaplin, & George, 2000) This form of sexual dimorphism is due to the requirement in human females for high amounts of calcium during pregnancy and lactation. Breastfeeding newborns, whose skeletons are growing, require high amounts of calcium intake from the mother's milk (about 4 times more than during prenatal development), (Kovacs & Christine, 2008) part of which comes from reserves in the mother's skeleton. Adequate vitamin D resources are needed to absorb calcium from the diet, and it has been shown that deficiencies of vitamin D and calcium increase the likelihood of various birth defects such as spina bifida and rickets. Natural selection has led to females with lighter skin than males in all indigenous populations because women must get enough vitamin D and calcium to support the development of fetus and nursing infant and to maintain their own health (Jablonski & Nina, Living Color,