Homo Aquaticus?
Homo Aquaticus?
I. Introduction
When the human brain is compared with the brains of apes there are several obvious differences; the centers for the sense of smell and foot control are larger in apes than in humans, but the centers for hand control, airway control, vocalization, language and thought are larger in humans. In my paper, I will describe the most defined differences of brain size and centers between humans and their closest relatives, chimpanzees, to compare them with other mammals and to draw conclusions about the evolution history of humans.
II. Brain Evolution
Humans and chimpanzees are biochemically (DNA) and therefore probably phylogenetically (evolution relationships), more alike than chimps and gorillas.
But the brains of chimps and humans differ in size and anatomy more than gorillas and chimps. The brains of chimps and gorillas probably didn't go through many evolutionary innovations, because they generally resemble other ape and monkey brains. This implies that the human brain changed a lot after the human/chimp evolution. With the exception of the olferactory bulb (scent), all brain structures are larger in humans than in apes. The neocortex (part of the cerebral cortex), for instance is over three times larger than in chimps, even though chimps and humans are pretty close to equal in body weight. Each side of the brain is diveded by the central sulces into independant halves. Just before the central sulcus lies the post-central cortex, where the opposite body half (right side for left brain, left side for right brain). Just in front of the central sulcus lies the pre-central cortex where the information for the voluntary movements leave tthe brain. The pre-central area is called primary motor cortex, and also "Area 4" in primates.
III. Human and Chimp Cortex Differences
In humans Area 4 is almost twice as large as it is in chimpanzees. The part of Area 4 that
I. Introduction
When the human brain is compared with the brains of apes there are several obvious differences; the centers for the sense of smell and foot control are larger in apes than in humans, but the centers for hand control, airway control, vocalization, language and thought are larger in humans. In my paper, I will describe the most defined differences of brain size and centers between humans and their closest relatives, chimpanzees, to compare them with other mammals and to draw conclusions about the evolution history of humans.
II. Brain Evolution
Humans and chimpanzees are biochemically (DNA) and therefore probably phylogenetically (evolution relationships), more alike than chimps and gorillas.
But the brains of chimps and humans differ in size and anatomy more than gorillas and chimps. The brains of chimps and gorillas probably didn't go through many evolutionary innovations, because they generally resemble other ape and monkey brains. This implies that the human brain changed a lot after the human/chimp evolution. With the exception of the olferactory bulb (scent), all brain structures are larger in humans than in apes. The neocortex (part of the cerebral cortex), for instance is over three times larger than in chimps, even though chimps and humans are pretty close to equal in body weight. Each side of the brain is diveded by the central sulces into independant halves. Just before the central sulcus lies the post-central cortex, where the opposite body half (right side for left brain, left side for right brain). Just in front of the central sulcus lies the pre-central cortex where the information for the voluntary movements leave tthe brain. The pre-central area is called primary motor cortex, and also "Area 4" in primates.
III. Human and Chimp Cortex Differences
In humans Area 4 is almost twice as large as it is in chimpanzees. The part of Area 4 that