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6 of 6 people found the following review helpful:
5.0 out of 5 stars
"When the tiger comes, freeze . . .", March 31, 2002
This review is from: The Cooperative Gene: How Mendel's Demon Explains the Evolution of Complex Beings (Hardcover)
Our view of life is usually pretty limited. Seeing trees, the family dog, winging birds, ourselves, we forget, if we ever knew, that complex life forms are in the historical and numerical minority. Even after 3 thousand million years, single-celled animals have the longest duration and largest population. Globs of material with a string of molecules, which we call "bacteria" were and are the most common form of life. Mark Ridley traces how those simple creatures underwent a radical change. They became restructured in a revolutionary step that would enable highly complex life to exist and evolve. Part of that revolution was the development of the most absurd concept in life's long history - sex. Gregor Mendel investigated the passing on of traits by counting peas. Ridley introduces an avatar, "Mendel's Demon" to explain how sex regulates what is passed on in us. In this superbly written account, Ridley clearly explains the advantage sex has in the evolution of life. He uses the children's game of Chinese Whispers [called Gossip in my childhood] to explain how evolution operates. In Gossip [forgive the chauvinism], a group of children whisper a message from one to another. Record the original message "when the tiger comes, freeze." Compare it with the version expressed by the final child. There will certainly be changes. In almost all occurrences, the errors are in misunderstood whole words, not just letters - "freeze" becomes "wheeze." The "words" of life are our genes. Acting as instructions to forming a new individual, the message must be clear enough to build the organism. That organism must survive to produce another. Sex provides ways of assessing the message to assure its validity before generating an offspring. Ridley goes on to discuss how complex life forms emerged. The most important steps were the protecting of DNA in a cell nucleus and the addition of mitochondria. Mitochondria are the energy modules of cells - chloroplasts in plants probably being the best known. Their joining the nuclear cell provided a trade-off. Mitochondria were given a place to live, paying rent by transferring much of their DNA to the cell's nuclear version. Once these two changes had been achieved, sex evolved with mechanisms to overcome the problems of DNA playing Gossip. Ridley shows how the processes surrounding sex overcome the mistakes that inevitably occur in the copying process. Gross errors don't survive - indeed they rarely achieve the development level of a fetus. The apparent dichotomy here is that while reducing errors may mean conserving an organism's traits, it may also reduce the diversity necessary to survive in a changing environment. The balance is delicate, as the fact that 99.9 per cent of all species having gone extinct over time testifies. Ridley sensibly brings each detailed description of the cell's processes back to how it relates to humans. This ploy is highly successful in making the book readable and focussed. It also builds a framework for the concluding chapters. After his thorough analysis of the procedures of reproduction and evolution, Ridley goes on to some highly speculative notions about the future. He notes that our species carries more genetic errors across generations than any other species. Could this error rate lead to what he calls "mutational meltdown"? Possibly, but not likely. Having speculated on conditions of life on alien worlds, he uses those ideas to suggest future scenarios to prevent that "meltdown." That bugaboo of today's society, cloning, Ridley dismisses as too vulnerable to natural selection. Instead, he sees gradually improving methods in using genes for therapy, organ replacement or repair, possibly even a drastic change in gender identity. Ridley's almost anecdotal style makes this overview of a complex topic an absorbing read. Reaching from deep history to a plausible future he covers much ground. His imagery retains your attention and he carefully builds your knowledge as you follow his lead. He's also careful with his science. No assertions are put forward without good foundation, and where the evidence is lacking or slim, he cautions us about coming to conclusions. The balance is so carefully maintained that this book might be considered a call for research in particular areas. Formidable and challenging, this is a delightful book for countless reasons. Intriguing questions, bold but realistic speculation, sound science vividly presented. A rich treasure, this book will be valuable until all Ridley's questions are resolved. Note to those who have found the title a problem, be aware that this book was originally published as: Mendel's Demon: Gene Justice and the Complexity of Life. Why the title was revised for U.S. publication remains elusive.
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16 of 20 people found the following review helpful:
3.0 out of 5 stars
Nice Book with a Misleading Title, September 1, 2001
This review is from: The Cooperative Gene: How Mendel's Demon Explains the Evolution of Complex Beings (Hardcover)
The title of this book is clearly a reference to Richard Dawkins' famous "The Selfish Gene." One of the most amazing develpments in evolutionary and developmental biology in the past couple of decades is that evolution is just as much about cooperation as it is about competition. In particular, several authors, including Maynard Smith and Szathmary, Michod, and Keller (see his Princton U Press collection) have analyzed the development of multicellular organisms in a conflict/cooperation framework. The result is quite unfavorable to Dawkins' approach. This book mentions the problem, but disposes of it so rapidly that virtually nothing of interest can possibly get through to the reader. Rather, this book is about the problem of replication error in copying dna. Ridley argues that the level of complexity of organisms is limited by their ability to sustain highly accurate copying, and that humans are about at the limit of this ability. This is a interesting argument, but to my mind it isn't earth-shattering and it doesn't require a whole book to tell. Of course, you will learn a lot of biology in the telling (if you didn't know it already), and Ridley is a very good writer. Ridley flirts with eugenics in the policy section of the book, lamenting that modern wealth, technology, and medicine allows lots of defective genes to proliferate in society, but he does not recommend doing anything about it---such as forcing people to abort imperfect fetuses. He argues that cloning shouldn't replace sexual reproduction because, whatever the value of sexual reproduction (Ridley is agnostic, but favor Kondrashov's model), it's clearly valuable. But we don't need a book or copying accuracy of dna to tell us that. In sum, nothing monumental here, but very nice if you want to learn a little about how modern biologists think, and what they think about.
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5 of 5 people found the following review helpful:
4.0 out of 5 stars
Fascinating Premise; Witty Writing; Vague Explanations, October 6, 2004
I don't know if Mark and Matt Ridley are brothers, but they should be. Each is English, has a doctorate, and writes in an engaging and literate way about evolution. Matt seems more interested in what is called "evolutionary psychology", discussing social issues in the light of our evolved traits. Mark is more the scientist, pursuing the fundamental questions of life. This book is about such a question: why did complex life evolve at all?
At first that might not seem like much of a question. The hard part, after all, is to get "simple" life -- a bacterium. After that, given enough time and the creative power of DNA mutations, complex life is more or less inevitable. Right?
Actually, from the evidence it seems that simple cellular life evolved rather quickly -- within a few hundred million years at most -- after it was possible for any life -- that is, after the planet had cooled down and water was mostly liquid. Yet, after that it may have taken two billion years for the eukaryotic cell to arise. That is such a large part of the total amount of time life has been on the planet that it is very possible that the eukaryotic cell might never evolve at all if the history of life were rerun.
And, according to Mark Ridley complex life -- multicellular life -- only arose because the genetic mechanisms invented by the eukaryotic cell allowed it. Complex life is complex because it has lots of parts, and requires lots of DNA, which must be duplicated from generation to generation. Copying errors turn out to be a limiting factor once you get to billions and billions of "letters" in your genome, even with the various enzymatic mechanisms for checking and correcting DNA copies (invented by bacteria billions of years ago and never improved upon). For bacteria, 99% of their offspring are perfect genetically, since their DNA is short enough that errors are unlikely. For us, we're lucky to get one or two perfect gametes in a hundred. So how in the world can we go on, generation after generation without degrading like a much-xeroxed document?
In a word, sex. This is really the crux and subject of the book: sex, gender, and the peculiarities of meiosis are there to overcome the daunting problem of copying error and allow beings with lots more DNA than a bacterium to quite faithfully reproduce themselves generation after generation. Even without any steamy scenes sex and gender are fascinating, and Ridley's explanation of why we have them (sex and gender are not the same thing) is convincing and entertaining. But I will say no more about that. You will just have to read the book, which I recommend, with some reservations.
I like Mark Ridley's writing. His sentences are graceful and laced with wit and learning. Where he falls down, though, is in the explanations, or justifications, for the material he introduces. The ideas of copying error and how it plays out in different organisms was new to me, as were the arguments justifying sex, gender, and the peculiarities of meiosis. On the way to them there were also various subsidiary conclusions, and in few cases were his explanations terribly coherent. At least part of this book had its genesis in lectures, and it shows. There are small inconsistencies: he refers to the new result of 30,000 genes in a human, for example, and later casually throws in the older presumption of 100,000, no doubt in a section lifted from an earlier talk and never corrected. But more annoyingly, his basic style of argument is what an old math professor of mine called "hand-waving". This is where you talk fast and plausably to skate over difficult points rather than using logic. Lectures to a lay audience tend to be mostly gee-whiz facts, jokes, and hand-waving arguments. Ridley is not that casual here, but still induced a kind of mental whiplash by discussing in excessive detail rather obvious points, and then making a sudden jump across an intellectual chasm to a daring conclusion, then blandly continuing.
In conclusion, I would recommend the book for its very interesting subject matter and breezy style. But I would add that you might find yourself wishing for a bit more rigor. Or not.
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