Evolving Brains (Scientific American Library) [Hardcover]

John Morgan Allman (Author)

Book Description

ISBN-10: 0716750767 | ISBN-13: 978-0716750765 | Publication Date: January 1999

Neurophysiologist John Allman draws on the wealth of new findings in molecular genetics and paleoanthropology to trace the history of brain evolution from the simplest of animals to human beings. In doing so, he explores the forces and mechanisms that have influenced evolutionary development, including climatic change, the energy requirements of large brains and the invention of the extended family in early humans.

Editorial Reviews

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

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."

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Product Details

• Hardcover: 224 pages
• Publisher: W H Freeman & Co (January 1999)
• Language: English
• ISBN-10: 0716750767
• ISBN-13: 978-0716750765
• Product Dimensions: 10 x 9.2 x 0.9 inches
• Shipping Weight: 7.2 ounces
• Average Customer Review: 5.0 out of 5 stars  See all reviews (11 customer reviews)
• Amazon Best Sellers Rank: #1,023,004 in Books (See Top 100 in Books)

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Most Helpful Customer Reviews

17 of 18 people found the following review helpful:

5.0 out of 5 stars Mind expanding material, January 11, 2001

By 

M. Dodson (Pennsylvania) - See all my reviews

This review is from: Evolving Brains (Scientific American Library Paperback) (Paperback)

How has the emergence of the super-sized human brain depended on the evolution of a good set of teeth? Why are the stomach and brain closely linked across the brambles of genetic code? This book answers not only those intriguing questions but also many others concerning the emergence of the brain on this planet. Especially fascinating to me was the explanation of the homeobox phenomenon, a process by which very complex mutations can arise in an organism without the mutation risking certain disaster. Being a non-biologist, I found this homeobox material quite fascinating, for it opened my eyes to how evolution could generate incredibly complex features without requiring a hundred trillion years for all the right components to come together all at once. Equally interesting are the many vestiges of our evolutionary past that are still embedded in the way our brains process information. For example, the sectors into which our brains split each of our retinae today for the purpose of signal processing: these are left overs from the days when our ancestors were prey and not predators, back when our ancestors' eyes were mounted to the sides of their heads! In summary, I would like to say that in reading this book, while just sitting in my chair, I felt myself moving up another notch on the evolutionary tree. It gave me a whole new appreciation for the miracle that is the development of brains and conscious life on this planet. A very pleasant read.

13 of 13 people found the following review helpful:

5.0 out of 5 stars From small beginnings . . ., May 10, 2003

By 

Stephen A. Haines (Ottawa, Ontario Canada) - See all my reviews
(VINE VOICE)    (HALL OF FAME REVIEWER)    (REAL NAME)   

This review is from: Evolving Brains (Scientific American Library Paperback) (Paperback)

This is a sweeping examination of evolution's path leading to that mass of gray matter behind your brows. Allman has synthesized a wealth of research in producing this study. He explains in a clear, interesting style how natural selection has spent the last 500 million years tinkering with life to build complex systems from simpler ones. He is a forceful writer, supplementing a fine text with superb illustrative material to build his narrative. It's a refreshing view of natural selection's power of innovation.

Allman draws on the detailed research undertaken in recent years that has mapped the brain and detailed its operations. Like all life, beginnings were simple, but small variations among organisms had the potential for important roles. Deep in the Precambrian, floating cells developed appendages leading to hair-like structures we call "cilia". The cilia adopted dual roles: sensing the environment and responding to it. Allman explains how gene duplication led to opportunities for experiments. This process demonstrates how we can track many of steps leading to today's life forms. The original genes are usually still resident, with enhancements providing new functions added over the passing generations.

The author's explanation of the workings of chemistry in brain functions is worth close attention. Behaviour is the result of brain activity, but the interactions of various parts and functions of the brain elude simple analysis. One example is the brain chemical [neurotransmitter] serotonin which is found throughout the brain. It's impact gives monkeys their social structure while adding to the risk of suicide in humans. Neurochemistry alone doesn't explain the expansion of the human brain, nor does the author stop there. He goes on to show how bipedalism, diet, language and social behaviour all working in self-reinforcing feedback loops led to the gob of tissue that takes a fifth of our body resources to keep working. Even global climate changes played a role, coming at a time when our species was just prepared to contend with them.

The number and impact of revelations in this book are almost beyond counting. The "urban myth" that women live longer than men because of improved health practices has been disproved both by history and anthropology. A study reaching back into the 18th Century demonstrates that women have outlived men at least that long ago. Among the great apes, chimpanzee females also outlive their mates. Orangutans and gorillas have nearly parallel life spans between genders. There are also studies showing how caring fathers have extended life spans. His analysis of the development of colour vision is another novel thesis. Colour perception arose only 40 million years ago, after the demise of the dinosaurs. This raises again, the question of whether the emergence of flowering plants, which were toxic to those creatures, helped speed their demise.

While this book is not a light read, it's an informative and edifying one. Allman deals with complex topics. Adding to the elaborate range of material involving the brain, behaviour and social issues is the background of the immense time spans required in dealing with these questions in the context of evolution. Given all these constraints, he has met the challenges of the task credibly and lucidly. [stephen a. haines - Ottawa, Canada]

18 of 20 people found the following review helpful:

5.0 out of 5 stars Everyone should read this book!, February 2, 1999

By 

Deborah R. Castleman (Santa Monica, CA USA) - See all my reviews

This review is from: Evolving Brains (Scientific American Library) (Hardcover)

This is a book to savor, to read again and again. After reading it, I found myself looking at the world and our place in it in a new, expanded way. A lot of scientific advances have been made in the past decade or so, and this book brings the reader up-to-date and ties together the advances made in various fields in an interesting, understandable manner. This book was written by a Professor of Biology at Caltech, who obtained his doctorate in anthropology. It has some chapters that take concentration to read, and others that one can breeze through. The pictures and graphics are great (this book will look good on your coffee table). No prior background in biology or anthropology is assumed. Probably what was most useful to me was that I learned a lot about evolution that I hadn't known before. Before reading this book, I thought that I had a basic understanding of evolution, but now I realize that the part I more or less understood was simply that of natural selection (Darwin). By walking the reader through the recent advances in genetics, this book explains in a clear and understandable way HOW NEW SPECIES ARE CREATED. (In my informal polling of knowledgeable friends and relatives, I found no one else who understood how new species are created... of course, with my new knowledge, I explained it to them!) Speaking of which, this book has resulted in some lively and engaging conversations: I now have a seemingly endless source of fascinating insights about humans, about animals, about the brain that I can talk to others about. Take dogs, for example. I have never been much of a dog-lover, but now I more fully appreciate how dogs (having evolved from wolves with the help of humans) and humans have worked together to ensure each other's survival... so now I don't mind it so much when my sister's dog jumps on my couch! Other examples: how the extended family structure (and therefore the role of females in general) has played in the survival of humans. How serotonin and the level of this chemical affects the brain (and thus why Prozac and other anti-depressants are effective). How our 'junk DNA' creates a fossil record of evolution. How our eyes and vision evolved... amazing! I could go on and on with such examples from the book, such wonderful things I learned. With my enhanced understanding I find myself noticing more about babies and how they learn, about animals... and tuning in to the new animal channel on cable more often. This book has excited a curiosity in me, and I want to learn more. I believe that everyone would benefit greatly from reading this book.