Encephalization is defined as the amount of brain mass exceeding that related to an animal's total body mass. Quantifying an animal's encephalization has been argued to be directly related to that animal's level of intelligence. In fact, as early as 1871, Charles Darwin wrote in his book The Descent of Man: "No one, I presume, doubts that the large proportion which the size of man's brain bears to his body, compared to the same proportion in the gorilla or orangutan, is closely connected with his mental powers." The human brain In animals, the brain (enkephalos) (Greek for in the skull), is the control center of the central nervous system, responsible for behavior. ... Brain to body mass ratio (also known as the Encephalization Quotient or EQ) is a rough estimate of the possible intelligence of an organism. ... For other uses, see Intelligence (disambiguation). ... For other people of the same surname, and places and things named after Charles Darwin, see Darwin. ...

Williams^[1] has recently argued that the most accurate means for quantifying the encephalization of humans and other adult primate species requires the use of Lapicque's universal exponent of 0.28 in Snell's equation of simple allometry. Since Lapicque's slope was derived from various vertebrate groups, this equation may potentially be universally applicable for determining relative adult vertebrate encephalization and intelligence. Allometry is the science studying the differential growth rates of the parts of a living organisms body part or process. ...

Encephalization may also refer to the tendency for a species toward larger brains through evolutionary time. Anthropological studies indicate that bipedalism preceded encephalization in the human evolutionary lineage after divergence from the chimpanzee lineage. Compared to the chimpanzee brain, the human brain is larger and certain brain regions have been particularly altered during human evolution^[1]. Most brain growth of chimpanzees happens before birth while most human brain growth happens after birth^[2]. Anthropology (from the Greek word άνθρωπος, human) consists of the study of humankind (see genus Homo). ... A biped is an animal that travels across surfaces supported by two legs. ... Type species Simia troglodytes Blumenbach, 1775 distribution of Species Pan troglodytes Pan paniscus Chimpanzee, often shortened to chimp, is the common name for the two extant species of apes in the genus Pan. ...

In 2004, Dennis Bramble and Daniel Lieberman proposed that early Homo were scavengers that used stone tools to harvest meat off carcasses and to open bones. They proposed that humans specialized in long-distance running to compete with other scavengers in reaching carcasses^[2]. It has been suggested that such an adaptation ensured a food supply that made large brains possible. Species Homo sapiens See text for extinct species. ... The human brain controls the central nervous system (CNS), by way of the cranial nerves and spinal cord, the peripheral nervous system (PNS) and regulates virtually all human activity. ...

More encephalized species tend to have longer spinal shock duration. // Spinal cord transection can be divided into two types, complete transection (spinal shock) and hemitransection. ...

References

In-line

1. ^  See Figures 1 and 2 of "Molecular insights into human brain evolution." by J. Bradbury in PLoS Biology (2005) volume 3 page e50. (Full text online)
2. ^  "Endurance running and the evolution of Homo" by D. M. Bramble and D. E. Lieberman in Nature (2004) volume 432 pages 345-352. Entrez PubMed 15549097

1. ^ Primate encephalization and intelligence - M. F. Williamsf1 - Oakland, USA
2. ^ see: Heterochrony

Nature is a prominent scientific journal, first published on 4 November 1869. ... The Entrez logo The Entrez Global Query Cross-Database Search System allows access to databases at the National Center for Biotechnology Information (NCBI) website. ... In biology, heterochrony is defined as a developmental change in the timing of events, leading to changes in size and shape. ...

Other

• Williams MF., Primate encephalization and intelligence. Med Hypotheses. 2002 Apr;58(4):284-90.

• Jerison H. J. Paleoneurology and the evolution of the mind. Scientific American 1976; 234: 90-101.

• Tobias P. V. The Brain in Hominid Evolution. New York and London: Columbia University Press, 1971.

See also

• Cephalization
• Human evolution
• Human brain
• Aquatic ape