Researchers report that the proportion of different functional areas of the animal's brain to the total brain mass is an important feature of the species. They found that in the same species, there may be significant differences in brain capacity between different individuals, but the characteristics of brain structure are basically the same; the structural characteristics of different species are quite different. Based on this, the researchers believe that the structural characteristics of the brain will help distinguish the genetic relationship between different species. They also pointed out that the changes in the brain structure usually mark the creation of a new population by evolution. For example, from the more primitive lemur to the current monkey; from the ape to the human, the main change in the brain is the increase in the proportion of the new cerebral cortex.
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The similarity of the brain structure of chimpanzees and gorillas is greater than that of chimpanzees and monkeys