Product Description

The existence of complex life is one of the great mysteries of evolution, for complexity is neither inevitable nor necessary. Indeed, as Mark Ridley shows in this important and thought-provoking book, two major biological hurdles had to be overcome to allow living complexity to evolve. Complex life is constructed from more genes than simple life. But as gene numbers increase, so too do the number of copying errors - it is easier to make a mistake copying the Bible than copying an advertising slogan. Similarly, natural selection encourages gene selfishness, and genes could easily evolve to subvert complex life forms. In retracing the history of life on our planet - from the initial wobbly replicating molecules, through microbes, worms and flies and ultimately to humans - Ridley reveals how life has evolved as a series of steps to deal with error and coerce genes to co-operate within each body. Mendel's Demon offers startling novel perspectives on matters as disparate as the origins of sex and gender, potential cures for AIDS, corporate mergers and acquisitions, and the long-term perils of human cloning.

Product Details

• Amazon Sales Rank: #544138 in Books
• Published on: 2001-06-07
• Original language: English
• Binding: Paperback
• 432 pages

Amazon.co.uk Review
In contradistinction to the more populist of science authors, Oxford zoologist Mark Ridley (not to be confused with Matt Genome Ridley) is unafraid to pitch his acclaimed books (like Evolution, and Animal Behaviour) at a discerning and cerebral audience. In other words don't go reading this analysis of genetic and sexual complexity expecting laugh-a-minute anecdotes about transvestite sparrows.

That said, those who are willing to persevere through the dense and unashamedly highbrow text will find an interesting debate cogently and wittily argued. Ridley's self-posed question is why such complex beings as swans, gibbons and journalists should have arisen, given an evolutionary process far more favourable to the replication of simple organisms. After all, each time we have sex, reproduce and thus copy our DNA, we are attempting the equivalent of xeroxing James Joyce's Ulysses. Mistakes can and will creep in. So why bother?

Ridley's search for an explanation of this puzzle leads him up some fairly precipitous intellectual mountains. Nor is he unafraid of tackling the wilder kinds of speculation: at one point he considers the sex lives of angels--or any putative beings superior to homo sapiens. Readers willing to accompany the author on this demanding expedition, and stretch their brains as a result, will find the exercise as stimulating as it is edifying. --Sean Thomas

About the Author
Mark Ridley is in the Department of Zoology at the University of Oxford. He was formerly assistant professor of anthropology and biology at Emory University, Georgia, USA. He has also been a research fellow at St Catherine's College, Cambridge, and at Linacre, Oriel and New Colleges, Oxford. He is the author of the acclaimed student textbook Evolution and is a regular contributor to The New York Times, The Sunday Times, Nature, New Scientist and The TLS, among other publications. Mendel's Demon is his long-awaited trade debut.

Customer Reviews

Another science book for the intelligent (or brave) layman
Which is one way of saying that it's an excellent book in that hazily defined area of popular science. The concepts though may be a little tricky for someone who has never had any scientific training, although I would recommend that anyone in this situation stick with the book as it is a very rewarding read and you will look around the world afterwards as if someone has switched the light on. Ridley explains some evolutionary puzzles in great detail but doesn't lose the reader along the way. It's worth the read just for the amusing speculations on the reproduction of divine creatures... The book takes you step by step through the concepts so that by the end you'll have gained a lot of knowledge and been enjoying yourself too much to notice. An excellent book that is exactly what you could hope for in a popular science book. Very good for someone studying biology (as I am) wishing to gain some background information or just to fill in the gaps for what's not covered in class.

The demon that shuffles and deals
Mark Ridley argues that since life started on the Earth almost as soon as it possibly could, after the planet cooled down sufficiently and the rate of bombardment from space slowed to a tolerable rate, it must be easy for life to get start. So it isn't life itself that requires explanation, but complex life, which took a long time to evolve after the first simple, single celled life began. He considers the possible reasons that life on Earth is not still made up entirely of bacteria and viruses. What would drive life to become complex instead of staying simple and what conditions would allow life to become more complex? According to Ridley, it's all down to sex and fidelity (faithful copying of genetic information).

He describes a series of ceilings that limit the increase in complexity from one level of evolution to another. The high rate of copying errors in RNA based life was an early ceiling. New complexity was enabled by the evolution of DNA. DNA based life could have more genes than RNA based life. More complexity requires more genes and more genes to copy means an increase in the copying error rate. As the number of genes increased the danger of 'mutational meltdown' increased. DNA errors were reduced by the evolution of proofreading enzymes to prevent errors and then other enzymes to repair DNA errors, then more enzymes to correct the expression of errors when they slipped past the proofreading and repair enzymes. And each higher level of copying fidelity allowed an increase in the number of genes and, therefore, the level of complexity. The reason life takes the opportunity to become more complex, is that niches are available for new life-forms to evolve and fill. It was the evolution of sexual reproduction that made it possible for life to reach its current high level of complexity. Initially it generated almost as many problems as it solved, with gene in-fighting and dirty tricks. After long and arduous teething troubles, resulting in such familiar solutions as gender (with females supplying eggs, complete with mitochondria and males provided sperm and keeping their mitochondria to themselves), a fiendishly clever system of random gene shuffling, that Ridley attributes to "Mendel's Demon", evolved, to concentrate copying errors in some offspring whilst enabling some error-free offspring to be produced and also, to hide information from 'law-breaking' genes that natural selection would favour if it was possible for them to 'know' which reproductive cells contained which genes. He wonders whether humanity is currently banging it's head on a ceiling or further complexity is still possible without another advance on the gene copying front. As an example of higher complexity, he considers angels and speculates about their mating habits and how many genes there might be in the angelic genome.

It's an interesting subject (pontificating on sex between supernatural entities aside) and Mark Ridley's book is full of intriguing notions - some more credible than others. I also found Matt Ridley's (that's MATT, the other Ridley, not MARK) ideas - set out in his book, "The Red Queen" - very compelling. His emphasis is on the tremendous advantage sexual reproduction gives in the arms race against parasites and disease, rather than the boost it gives to the evolution complexity. Both the Ridleys' arguments seemed convincing. But then, neither excludes the other and I can see no reason why sex shouldn't serve more than one purpose.

The best book on genetics for years
This is a stunningly good book. Ridley tackles the problem of how complex life has evolved despite the seemingly intractable problems of genetic copying errors and the evolutionary pressure for selfish genes. It's a remarkable achievement to explain so many of the current concerns of geneticists so clearly: I write as a non-professional for whom many of the concepts were entirely new, but I was still hooked by the sheer drive and intelligence of Ridley's exposition. He's got a talent for selecting the right analogies, and a pleasantly dry wit. I found it wonderfully stimulating to follow the twists and turns of the argument as a rigorously Darwinian logic is applied to the problems of the evolution of complexity. And there are some surprising and profound insights along the way, especially in the area of sex and gender. There's also the most intelligent discussion I've come across of the future of human evolution. What more can I say?....thoroughly recommended!