- Hardcover: 256 pages
- Publisher: Rutgers University Press (31 July 2000)
- Language: English
- ISBN-10: 081352783X
- ISBN-13: 978-0813527833
- Product Dimensions: 2.3 x 15.9 x 23.3 cm
- Amazon Bestsellers Rank: 1,158,202 in Books (See Top 100 in Books)
"Human evolution," McKee writes, "has been the product of many forces that together made us neither inevitable nor probable." The same holds true for other species; with all due respect to Lamarck, McKee adds, the giraffe came to have its long neck by a roll of the genetic dice--but a roll that lent the giraffe a competitive advantage over its shorter-necked browsing cousins, and therefore one subsequently reinforced by natural selection. Illustrating his argument with the well-worn "butterfly effect"--wherein a butterfly flapping its wings in Europe can produce a typhoon half a world away--McKee examines the role of chance in the origin and decline of species, emphasising how unpredictable the dynamics of life can be even within the bounds of natural laws.
Within such disorderly circumstances, McKee observes, chance favours species that retain generalised features and behaviours; whereas, he writes, "the fossil record is littered with extinct primates that became too specialised," the ancestors of modern humans were broadly diversified, adapting to different niches and thriving in the bargain. Well written and written at an appropriately general level, McKee's book offers a useful survey of current evolutionary thought. --Gregory McNamee
Although McKee's informal style and frequent flashes of humor make for pleasant reading, the book also has much to teach. Its central theme reflects the growing realization among scientists that spontaneous development to the level of thinking, planning creatures is a rare event, perhaps much rarer than previously thought. The author puts it succinctly in his opening chapter: "....Human evolution has been the product of many forces that together made us neither inevitable nor probable."
Drawing from Chaos Theory, McKee explores the drastic consequences that minute initial-condition changes can cause in long-duration, many-branched processes such as biological evolution. At the end of such a process it may be impossible to distinguish the contributions of truly random events, such as gene mutations and natural disasters, from the deterministic but random-appearing effects of chaotic variation. One way to "separate the variables" is to construct a simulation. Reporting on an example of such evolutionary modeling by computer, McKee describes surprising results that seem to confirm the famous "butterfly effect" often cited in time-travel science fiction.
Although he underscores the inevitable roles of chaos and unpredictability, McKee does not ignore the feedback phenomena that stabilized evolution and drove it in the direction of increasing complexity. Natural selection and its companion forces, gene flow and genetic drift, are given a thorough treatment which includes cases where selection fails, such as accidental early deaths unrelated to genetic fitness. An entire chapter is devoted to the concept of autocatalytic (self-driven) evolution and its continuing importance as advanced species like H. sapiens willfully modify their environment and replace natural selection with artificial selection through social policies and medical intervention.
One of the book's most engaging chapters underscores the limitations of evolution, such as having to fashion every new model by tinkering nondestructively with an existing one (in contrast to supernatural design, which could start each species with a clean sheet.) McKee amusingly details some of the dubious orthopedic compromises involved in raising mammals from quadruped to biped status, freeing their increasingly articulated front feet to become full-time hands.
In "A Tale of Two Sites," the author gives a fascinating account of his fossil-hunting during ten years in South Africa. While the main thrust of the book is dedicated to helping the reader understand big-picture issues in evolutionary anthropology, a detailed description of McKee's inspirations and frustrations in field work adds depth and practical substance to the theoretical portions of the book.
I greatly enjoyed "The Riddled Chain" and believe it will both entertain and educate anyone wanting to learn more about the awesome and mysterious, but not miraculous, origins of humanity.
The trick is that you don't notice how deep you've gotten. Just when your attention and understanding start to flag a bit, he pull in some amusing anecdote to make it all clear and keep you reading with a smile.
His main point is that chance, coincidence, and chaos are important and necessary for evolution. He demolishes the over-simplified theories that climate change leads to human adptations such as bipedalism.
Instead he proposes that evolution is self-driven. Chance events such as mutations must coincide with chance conditions, and then leads human evolution in one direction rather than another. He applies chaos theory, which I never understood until now, to show that small events can have big, long-term consequences.
The book ends with a look at our future evolution that is both interesting and scary.
McKee says in his preface that he thinks science is fun. His book certainly shows that. You'll have fun reading it, and you'll never think about human evolution in quite the same way you did before.
McKee goes to great detail in explaining the most acccepted evolutionary theories so that anyone can understand them. He then clarifies what he agrees with and what he doesn't and how those theories relate to his own hypothesis of natural selection. For example, I enjoyed the section dealing with how giraffes' circulation systems adapted as their neck length grew and now I can easily explain this to my sons.
I found the final chapter extremely thought provoking because it not only dealt with the past, but the future. I highly recommend this book for anyone to read and consider.