How did human beings evolve ?

How did an ape with a protruding skull and a protruding face become a modern man? This question has been debated for hundreds of years, and up to now there is no convincing perfect answer. However, most scientists agree with Darwin's theory of evolution and think that all living things evolved from their ancestors. The ancestors of modern people are Australopithecus. Among the top ten scientific advances in 2011 selected by science magazine of the United States, one is the new discovery of Australopithecus by scientists from many countries, believing that it is the best species of human ancestors.

Man is the highest form of animal, can walk upright, has a big head, can use language communication, can make tools, has consciousness and sociality. According to the fossil data, scientists believe that: about 4 million years ago, ancient apes evolved into Australopithecus, 2.5 million years ago, Homo erectus (ape man) appeared, 2-250000 years ago, Homo sapiens 250000 years ago, and modern man didn't appear until 100000 years ago. In addition to the obvious differences in skull and face shape between early Homo sapiens and modern people, the cranial volume of early Homo sapiens was very close, with an average of about 1440 ml. by more than 100000 years ago, it was difficult to distinguish between late Homo sapiens and modern people.

According to the hypothesis of evolutionary biologist Mayer and zoologist Kingdon, 7-5 million years ago, due to the dry climate and dead trees, the forest area on the earth was shrinking, and the ancient ape, who had been living in the forest for generations, faced the danger of breaking up its home. In order to breed, these ancient apes, who can climb and forage flexibly in the forest, have to find another way out. Besides forest, grassland is also an ideal resting place. However, the ancient ape is just a stranger to the grassland. The elephants, bison and other large animals that used to live there do not welcome these visitors. Once they meet in a narrow way, the ape can only escape. If it can't escape, it's either death or injury. In addition to elephants and bison, there are also fierce carnivores such as lions, tigers, leopards and wolves on the grassland. When they see this group of strange visitors from the forest, they will open their mouths and pounce on them. In an instant, the ancient ape will die. Apart from leaving a pool of blood, bone and meat have become the feast of beasts.

In this dangerous prairie, where life is always in danger, if the ancient ape can stand up, look around, observe the enemy's situation, and prepare for escape early, it can survive in the dangerous situation. So, in this life and death environment, those who survive are of course those ancient apes who can stand up and look out, and their forelimbs must be shorter than their hind limbs. These ancient apes continue to breed and become an upright walking population, which is the Australopithecus.

The upright walking Australopithecus didn't need to touch the ground on all fours, so their hands were liberated. The free hands were not only for predatory and self-defense, but also for taking care of infants and young children. When they met with natural enemies, they could also run away with their children. According to the research on the development of human brain and ape brain, we can know that there is a big difference in the cranial volume between human brain and ape brain. Human brain is larger than ape brain, so human is smarter than ape brain. However, the development of ape brain is obviously faster than that of human brain. The brain of the newborn ape is basically fully developed, otherwise the young ape will not be able to actively survive and grasp the mother. The infant who has just left the mother has no ability to survive except to croak and cry. If it is not taken care of, it will die. The upright walking Australopithecus could take care of their offspring with their free hands, which was conducive to reproduction, and thus evolved into Homo erectus and Homo erectus (ape man).