Humans have grown to this day with a population of over six billion. Because in the Primitive period, people living in different conditions and long-term evolution appeared different morphological characteristics. According to the general classification method, humans can be divided into races of humans: yellow, black, white, and brown.
The formation and development of human races are both influenced by social factors and controlled by natural conditions. Skin color is the most obvious result of human adaptation.
The black formation is associated with the hot tropical climate. Africa crosses the equator, and the Sun is hot as fire, the climate is harsh. People live there for a long time, and the skin is blackened, curly hair, white eyes, and teeth, the forehead is protruding, lips are thick and puffed out, the nose bridge is short, the nose is short, the beard is little, body hair is little. Black skin is mainly because the skin contains a very high black pigment. The skin of human races contains pigment cells. They are mainly distributed in the developmental layer of the skin. Black pigmentation cells are very sensitive to sunlight. Under the strong sunlight, the black pigment particles are created very quickly, in large numbers, distributed, and can extend to the grain layer of the skin surface, so the skin appears black.
Conversely, if the sunlight is weak, the black particle generation rate is relatively slow, the quantity is small, distributed according to the liquid state, so the skin color is white. When the black pigment is concentrated in the epigenetic layer, the skin is brown or dark brown. If the black pigment content is moderate, or the particles are evenly distributed, the skin becomes yellow or pale yellow.
The black pigment prevents ultraviolet rays from penetrating the skin, so people living in hot climates have darker skin tones, while those living in high latitudes have pale skin.
Black sweat glands are very well developed, so it is easy to dissipate heat. Black human hair is curled up like a hat. It can resist the strong Sun’s rays to protect the skin. Lips thick, mouth wide to increase the mucosal area of lips. The nose is short but wide for ventilation. These body features are also the corresponding adaptations of the body to the hot climates of the tropics and subtropics.
Northern Europe has weak sunlight and cold weather. People who live a long time in such an environment appear white.
Although the human race is different in skin color, the body organs’ structure is the same. Regardless of high or low, there is no inferior type, so racism is wrong.