In a human being the organs are developed from our evolutionary stream i.e. our ancestors. And the progression of life can be predisposed by a number of things that is inclusive of the climate, living necessities of the region, the vital involuntary genetic makeup in the human being that get altered owing to many grounds, say for example the food habits. We have temperate and tropical countries all over the sphere where the duration of the summer period is extended over duration of somewhere twelve months. Now talking about the countries in the tropical region the summer season extends approximately to six months. For African people the duration is vast as compared to the others. These people have the disadvantage of the growth of the pigmentation if their melanin in their skin and hence the lips are big. They are naturally so, it is the way nature tends to present itself.

The reason being their developing big lips are due to the environment they are living into. All Africans do not necessarily have big lips, however, for them who have so the reason being, their effective genes those are so strong that keep passing over and over from generations to generations. The reason why the genes stick to them is that there are internally many communities in Africans and that they prefer to get married in their own ones. So this characteristic of having big lips is retained in them from generations to generations. This is also true that all Africans do not have big lips.