The Riddled Chain: Chance, Coincidence and Chaos in Human Evolution - Hardcover

McKee, Jeffrey Kevin

Hardcover

ISBN 10: 081352783X ISBN 13: 9780813527833

Publisher: Rutgers University Press, 2000

Synopsis

Did human evolution proceed in an inevitable fashion? Can we attribute our origins solely to natural selection, or were more mischievous forces at work?

These are the questions investigated by anthropologist Jeff McKee. He argues that if we were to wind back the clock to our split from ancestral apes, evolution would proceed differently. Ever since our ancestors first stood up on two feet, natural selection undoubtedly was an important factor in guiding human evolution. But McKee shakes the standard notion that natural selection steered early hominids toward particular environmental adaptations. The fossil remains of our ancestors reveal a different story one of an adaptable hominid with no particular direction. It becomes clear that the evolutionary road to Homo sapiens was not paved solely by natural selection; indeed, there was no road to follow. There was just a dim path cut out by prehistoric coincidences and contingencies. Had any link in the evolutionary chain of events been slightly different, then our species would not be as it is today . . . or our ancestors may not have survived at all. 

With equal doses of humor and awe, McKee illustrates how the chain of evolution has been riddled by chance, coincidence, and chaos. He uses familiar examples, noting that many of us exist as individuals because of chance meetings of our parents. From the present back through prehistory, chance is at the heart of our creation is chaos. The classic example of chaos is the butterfly effect: a single butterfly, flapping its wings, causes a tiny change in the atmosphere, which in turn amplifies to affect the course of storms on another continent. McKee ties such examples of unpredictability to fossil evidence and computer simulations, revealing the natural coincidences that shaped our evolution. Although chaos exacted an evolutionary price by limiting the powers of natural selection, it also made us what we are. One can only conclude that human beings were neither inevitable nor probable.

About this title

About the Author

JEFFREY K. MCKEE teaches in the Department of Anthropology and Evolution, Ecology, & Organismal Biology at The Ohio State University. He is the co-author of Understanding Human Evolution.

From the Inside Flap

Did human evolution proceed in an inevitable fashion? Can we attribute our origins solely to natural selection, or were more mischievous forces at work?

These are the questions investigation by anthropologist Jeffrey K. McKee. He argues that if we were to turn back the clock to our split from ancestral apes, evolution would proceed differently. Ever since our ancestors first stood up on two feet, natural selection undoubtedly was an important factor in guiding human evolution. But McKee shakes the standard notion that natural selection steered early hominids toward particular environmental adaptations. The fossil remains of our ancestors direction. It becomes clear that the evolutionary road to Homo Sapiens was not paved solely by natural selection; There was just a dim pat cut out by prehistoric coincidences and contingencies. Had any link in the evolutionary chain of events been slightly different, then our species would not be as t is today... or our ancestors may not have survived at all.

With both humor and awe, McKee illustrates how the chain of evolution has been riddled with chance, coincidence, and chaos. He uses familiar examples, noting that many of us exist as individuals because of chance meeting of our parents. From the present back through prehistory, chance is at the heart of our creation-as is chaos. The classic example of chaos is the butterfly effect: a single butterfly, flapping its wings, causes a tiny change in the atmosphere, which in turn amplifies to affect the course of storms on another continent. McKee ties such example of unpredictability to fossil evidence and computer simulations, revealing the natural coincidences that shaped our evolution. Although chaos exacted an evolutionary price by limiting the powers of natural selection, it also made us what we are. One can only conclude that human beings were neither inevitable- nor probable.

Reviews

McKee wonders, as everyone must, how we got here. "How could an aimless evolutionary process, patching together random biological novelties and oddities through trial and error, lead to Homo sapiens?" Probably humans would not appear, he says, if evolution could have restarted. "This is because the evolution of life is subject to fates wantonly dictated by three ubiquitous and mischievous forces: chance, coincidence, and chaos." Elaborating on the effects of those forces, McKee proposes a bottom-up model of evolution rather than the top-down model favored by many evolutionists. "In the standard top-down model, outside environmental influences are more important, and the species is a pivotal unit. In the bottom-up model, genetic variants must be tested through successive levels within members of a species before any adaptation to outside influences can take place." And he suggests that because of the huge number of genetic variations made possible by the large human population, "our species may be set to evolve at an unprecedented rate." McKee, associate professor in the departments of anthropology and evolution, ecology, and organismal biology at Ohio State University, has a way with examples and analogies that greatly enhances his argument.

EDITORS OF SCIENTIFIC AMERICAN

Add culture to the alliterative subtitle and clever to describe the approach of the author, for this is indeed an intelligent and provocative account of human evolution. McKee (Anthropology/Ohio State) is a theorist as well as a field paleoanthropologist. He has worked on digs at the storied sites in South Africa (Magapansgat and Taung) where Raymond Dart discovered a famous fossil of a child hominid, not an ape, estimated to be about 2.5 million years old. The structure of the skull provided McKee with a starting-point for his thesis: there is chaos in the world, he claims, because a change in some initial circumstance in our evolutionary history--one that occurred by chance (gene mutation)--has had epoch-making and unpredictable repercussions. The Taung child was a small-brained, large-faced biped. In the process of adapting to standing and walking, McKee speculates, the spinal cord attached to the brain moved centrally so that the head would eventually sit squarely over the spinal column and face forward. These genetic and morphological events, along with evidence from other fossil finds and computer simulations, led McKee to conclude that evolution is self-catalytic (i.e., self-driven). It is the product of change, coincidence, and chaos, climaxing in human evolution with culture, that has increased our adaptability. McKee discredits the popular theory that a climatic cooling led to a loss of forest and the growth of savannahs, thereby driving our ancestors to bipedalism. He also includes a wonderful chapter cataloguing the compromises in anatomy and physiology our species lives with, and he speculates that we are preserving maladaptive traits because of our medical ingenuity. McKee's wonderfully rich and thought-provoking text, told with style and winning flashes of humor, is a refreshing entry into the always contentious and endlessly fascinating story of human origins. -- Copyright © 2000 Kirkus Associates, LP. All rights reserved.

Unlike most entries in the spate of recent books discussing human evolution, this book focuses on the processes that gave rise to humans rather than detailing the steps in our lineage. McKee, professor of anthropology at Ohio State, argues that evolution is much less directed than many people might believe. The dominant forces, he asserts, are chance, coincidence and chaos, coming together through the process of autocatalysis. McKee draws intelligently on his work on computer modeling to bolster his position. He shows, for example, that randomly removing just a single female from a simulated human population of 10,000 breeding individuals can have dramatic effects on the evolution of that population. In one such computer run, with a seemingly nondescript female removed, the population went extinct only 321 generations into the simulation. McKee also looks at the prospects for the future of human evolution, asserting that "the lessons of human evolution are important, have a broad value, and may even help us set the course for our future survival." We are continuing to evolve, he contends, in significant ways, from changes in eyesight to alterations in our immune system. Additionally, our actions are influencing the world around us to such an extent that our own continued existence is at risk. Although there's not much that's truly new here, McKee does an admirable job of presenting his ideas. (July)
Copyright 2000 Reed Business Information, Inc.

The role of chance in human evolution is often underemphasized by those who think in terms of purposeful change. As this book usefully demonstrates, chaos theory can give us clues about our own evolution. McKee (anthropology, Ohio State Univ.) uses computer simulations to show how apparently minute changes in the initial makeup of a simulated population cause enormous changes in the population after many generations. Environmental change does not cause evolution, he says; natural selection acts either to preserve or kill off mutations but is dependent on mutations occurring by chance to make any changes. McKee, who has excavated fossils in South Africa, is also a proponent of the role of autocatalytic evolution, in which an initial evolutionary change is affected by feedback loops. This means that the survival and spread of a mutation is affected by its impact on the functioning of the organism within its species and in the current environment and that it in turn can affect the survival of mutations in other parts of the organism. Most of McKee's ideas are not entirely new, but his working out of their implications leads to important and sometimes unorthodox insights. His clear, informal, and anecdotal writing style makes sometimes complex ideas interesting and understandable. For academic and large public libraries.DMarit MacArthur Taylor, Auraria Lib., Denver
Copyright 2000 Reed Business Information, Inc.

Edition details

• Publisher: Rutgers University Press
• Publication date: 2000
• Language: English
• ISBN 10: 081352783X
• ISBN 13: 9780813527833
• Binding: Hardcover
• Edition number: 1
• Number of pages: 294