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Evolving Brains (Scientific American Library) by John Morgan Allman

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Evolving Brains (Scientific American Library) John Morgan Allman
Language: English
Page: 224
Format: pdf
ISBN: 071676038X, 9780716760382
Publisher: W H Freeman & Co

Amazon.com Review

What's the big deal about big brains? They're a costly enhancement, says neurobiologist John Allman in Evolving Brains. "Animals with big brains are rare," he stresses. "If brains enable animals to adapt to changing environments, why is it that so few animals have large brains? The reason is that big brains are very expensive." He examines the whys and wherefores of large-brain evolution, and draws out the connections between large brains and long lives; shows why major evolutionary advances are often made by small predators; makes you appreciate why mammals, burdened by the cost of warm-bloodedness, were unable to unseat the dinosaurs; and more. So, while large brains such as the ones we humans enjoy may give survival advantages to individuals, some species have done (and did) just fine for millions of years with pea brains.

Rather than talking only about cells, circuits, neurotransmitters, and genes, or gliding up to the ethereal regions of psychology and philosophy, Allman looks at the whole organism--the "middle-sized, middle-distanced objects," as Willard Van Orman Quine said. Evolving Brains is full of interesting scientific tidbits, only rarely becoming tangled in the thicket of jargon. --Mary Ellen Curtin
--This text refers to an out of print or unavailable edition of this title.

From Scientific American

"Brains exist because the distribution of resources necessary for survival and the hazards that threaten survival vary in space and time," Allman writes. Even single-celled organisms such as bacteria have brainlike functions that enable them to find food and avoid toxins. Starting with the brainlike activity of Escherichia coli, the populous bacterial tenants of our intestines, Allman (professor of biology at the California Institute of Technology) traces the development of brains from small to large, simple to complex. His account focuses on three themes: "that the essential role of brains is to serve as a buffer against environmental variation; that every evolutionary advance in the nervous system has a cost; and that the development of the brain to the level of complexity we enjoy--and that makes our lives so rich--depended on the establishment of the human family as a social and reproductive unit." From that level of complexity he asks an intriguing question: Why has the human brain become smaller in the past 35,000 years? His answer: "The domestication of plants and animals as sources of food and clothing served as major buffers against environmental variability. Perhaps humans, through the invention of agriculture and other cultural means for reducing the hazards of existence, have domesticated themselves."
--This text refers to an out of print or unavailable edition of this title.