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Evolution Of The Brain
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Evolution Of The Brain

Poem By gershon hepner

All know that evolution of the brain
required an increase of size, but few
have realized that we would not be sane
if it had not been organized anew,
becoming so completely redesigned
that it could focus on activities
no ape would care about, by brain baselined
to practice primitive proclivities.
Society is growing every day,
but won’t improve till we reorganize
the access of its foes to right of way
through pathways that, destructive, they despise.
Till this is done society will fail
like those precursors of so-called mankind
who, unreorganized, retained their tail,
of which a trace remains within the mind.

Michael Balter writes about Ralph Holloway of Columbia University who ahs been making endocasts of fossil brains for nearly forty years (“In Study of Brain Evolution, Zeal and Bitter Debate, ” NYT Sciene Times, November 27,2007) :
We humans are rightly proud of our big brains. But most anthropologists now agree with Dr. Holloway that increases in size alone cannot explain advanced human cognition. There have also been structural changes that distinguish the brain of Homo sapiens from those of our hominid ancestors, as well as those of close cousins like the chimpanzee. “He will be remembered as the major advocate for an early reorganization of the brain in human evolution, ” said William Kimbel, a paleoanthropologist at the Institute of Human Origins at Arizona State University in Tempe….
After receiving his bachelor’s degree from New Mexico in 1959, Dr. Holloway worked a year as an engineer for Lockheed Aircraft to please his father, and then began anthropology graduate work at the University of California, Berkeley. He was hired in 1964 by Columbia, where he soon began to question the wisdom of the day about brain evolution. The turning point in Dr. Holloway’s research came in the late 1960s, when he traveled to South Africa to study fossils of what then were the earliest known members of the human family, the australopithecines. He was particularly keen to examine the so-called Taung child, the first australopithecine discovered. It was found in 1924 by Raymond Dart, an anatomist at the University of the Witwatersrand in Johannesburg, among fossils from a limestone quarry. The specimen, thought to be two million to three million years old, included an endocast of the child’s brain created when limestone had filled the skull’s interior. Dr. Dart announced he had discovered a species of “man-ape, ” which he named Australopithecus africanus. Among the features Dr. Dart identified was the lunate sulcus, a crescent-shaped furrow near the back of the brain that divides its occipital lobe, where visual information is processed, from the rest. The Taung child’s lunate sulcus, Dr. Dart reported, had been “thrust backwards” as it is in humans, rather than forward as in chimpanzees and other apes. The resulting size reduction of the occipital lobe, he concluded, had been accompanied by an enlargement of parts of the brain associated with higher cognitive functions. Dr. Holloway created endocasts of the Taung child and other australopithecine skulls. Although Dr. Dart’s conclusions had been controversial, Dr. Holloway confirmed the bulk of them, including the posterior location of the lunate sulcus. “The reorganization of the brain became clear, ” Dr. Holloway said. “These australopithecines had brains the size of apes, but they were bipedal, their hands were free, some of them might even have made stone tools. You can’t get this kind of behavior without rewiring and reorganization.”

11/26/07

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Beautifully portrayed information/concept


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