|Raven, Peter H. & Johnson, George B. Biology. Iowa: Brown, 1995: 443.||"Their brains were about the size of those of present-day gorillas, about 350 to 450 cubic centimeters in volume, as compared with an average volume of about 1450 cubic centimeters in modern humans."||1450 cm3|
|Milner, Richard. "Cranial Capacity." The Encyclopedia of Evolution: Humanity's Search For Its Origins. New York: Holt, 1990: 98.||"Living humans have a cranial capacity ranging from about 950 cc to 1800 cc, with the average about 1400 cc."||1400 cm3|
|Stringer, Christopher & Gamble, Clive. In Search of the Neanderthals. New York: Thames & Hudson, 1993.||"While the largest Homo erectus brains were about 1250 ml (2 imperial pints) and modern brains average about 1200–1500 ml in volume, female Neanderthal brains were about 1300 ml and those of males about 1600 ml, extending to 1740 ml in the Amud man."||1200–1500 cm3|
|Vilee, Claude A. Biology. Philadelphia: Saunders, 1954.||"Modern man has a brain volume of about 1500 cc, while the higher apes have a brain size of only 600 cc."||1500 cm3|
|Walker, Alan & Shipman, Pat. The Wisdom of the Bones. New York: Knopf, 1996.||"This went up to about 1075 cc in the Zhoukoudian fossils, and rose to about 1400 in Neandertals, whose brains were about the size of modern human brains."||1400 cm3|
|"A human baby's brain starts at 369 cc and increases, during the first year of life, to about 961 cc, after which the growth rate declines; adult cranial capacity is approximately 1345 cc."||1345 cm3|
|Oram, Raymond F, Hummer, Paul J. & Smoot, Robert C. Biology: Teacher's Annotated Edition. Ohio: Bell & Howell, 1983.||"Brain size was about equal to that of modern humans (about 1450 cm3)."||1450 cm3|
The brain is one of the most important organs because it controls so many of the body's functions. The brain makes up only 2% of the total body weight. Brain injury could result in permanent damage or even death. Therefore, it is very important for the brain to be protected.
The brain and spinal cord make up the central nervous system. The skull (cranium), made of bone, protects the brain. The three major sections of the brain are the forebrain, the midbrain, and the hindbrain. The forebrain includes the cerebrum, the largest part of the brain that takes up about two thirds of the brain. The cerebrum is divided into two hemispheres. It controls the interpretation of impulses from sense receptors, memory, learning, and emotions. The midbrain carries messages between the forebrain and hindbrain. The hindbrain is composed of the cerebellum and the medulla oblongata. The cerebellum controls all voluntary and some involuntary movements. It maintains balance and coordination. The medulla oblongata controls many involuntary functions such as breathing and heartbeat. If the medulla is destroyed, a person will die. The medulla is connected to the spinal cord, which connects the peripheral nervous system with the brain and controls reflexes (automatic responses).
Early humans are known as hominids. Australopithecus was the first human-like creature, that lived in Africa about 5 million years ago. Their brains were 350 to 450 cubic centimeters, the size of a gorilla. Homo habilis, which was more human-like, lived two million years ago and was the first to use stone tools. Their brain volume was about 700 cm3. The Neanderthals, which are more modern humans, are classified in the same species (Homo sapiens) as today's humans. However, living humans belong to a different subspecies, Homo sapiens sapiens. Although the Neanderthal brain was larger than that of humans today, it does not mean that the Neanderthals were more intelligent, because brain size is related to body size and the temperature of the environment.
The volume of a human brain, otherwise known as cranial capacity, varies depending on several factors, such as age, environment, and body size. The volume is usually measured in cubic centimeters (cm3 or cc). Modern humans have cranial capacities from 950 cm3 to 1800 cm3, but the average volume of a modern human brain is 1300 cm3 to 1500 cm3.
Viktoriya Shchupak -- 2001