In my Navy days, The Landing Force Manual was the guidebook for transforming sailors into combat soldiers. It was a catalogue of techniques teaching bivouacking, patrolling, land occupation and defense. Richard Dawkins has unabashedly given us a similar primer useful in learning to deal with those still resisting Darwin's concept of evolution by natural selection. Like The Landing Force Manual, "River Out of Eden" is an arsenal of topics that, once learned, may be applied in conversational combat with those still resisting the idea that evolution is the way life works. With thorough knowledge and captivating style, Dawkins gives us illuminating examples of how life has achieved what appear to be miracles.
Dawkins re-initiated the debate over evolution's mechanics with The Selfish Gene. For his lucid explanation of the gene as the foundation for life's workings, he was dubbed The Great Reductionist by those uncomfortable with the concept that genes tend to override the treasured idea of "free will" overriding Nature. With River Out of Eden, Dawkins proves his ability by presenting an even more comprehensible account of how DNA is the foundation for life's mechanics.
He begins with the idea that all life had ancestors - all of which succeeded in producing offspring. Their success at reproducing overshadows the fact that most life forms ultimately went extinct over the vast span of Earth's time. Extinction is due to failure to produce offspring that survived to further reproduce new generations. The reasons for this failure are uncountable and obscure, but the issue remains success or failure. Tracing the ancestral line allows us to envision rivers of life. The rivers aren't composed of water, but of DNA. DNA over time, acts as a "digital river" with sections turning on or off in the process of making proteins. And proteins are the bricks that build organisms and all their parts.
From an almost purely descriptive beginning, Dawkins moves on to demonstrate how many of those "parts" could evolve over the many millennia available to them. Among the favourite organs used to oppose natural selection is "the eye". How could such a complex part of life work half complete? Well, for starters, better than 49% complete. A statement that can be applied to all the body parts in various organisms when viewed over the long stretch of years available to change gradually. Wings, finding mates, locating food sources, all the "complex functions" we see in today's life came from earlier, simpler beginnings. Dawkins' chapter "God's Utility Function" is a must read and understand for anyone wishing to comprehend how many of these features came into existence. They didn't all arrive in a finished state.
Dawkins is adept at illustrating his points. Among his more clever tricks is the portrayal of a sentence reading clearly even with different typefaces for each word. You can still read and understand the meaning. But the appearance differs in each case. He also gives an excellent account of how genes govern energy expenditure for various types of creatures. Each has its own variant, but an "audit" of how the genes benefit from the arrangement reveals why it's a successful strategy.
The key to all these patterns is the idea that somehow, somewhen, a molecule that later became DNA learned to replicate. He posits Graham Cairns Smith's suggestion that DNA, or more likely its precursor, RNA, learned the trick from clay crystals. This remains the most likely explanation for life's origins, but requires the reader to recognize that the replicating molecule preceded any discernible organism. Cairns Smith's concept removes forever the idea that life's driving force occurred by chance. It was a relatively simple chemical and physical process. It may not appear elegant, but the mechanism has the elegance of plausibility.
This whole book carries the argument against "creation by design" into the camp of Darwin's enemies. Dawkins lists the contentions of the "creationists", then adroitly unravels them through pure logic and good science. Those who feel daunted by arcane biological treatises on life need only take up this excellent summation of why Darwin was right. Those who quail at the idea DNA drives our existence can take heart. It's all part of what's required in achieving a better idea of who we are. A major step in that understanding is in this book. [stephen a. haines - Ottawa, Canada\
on 15 December 2009
Having already read some Richard Dawkins's works and knowing that "River Out of Eden" is his shortest book and the least technical one, I was initially reluctant to reading it, but it turns out it was well worth it.
Subtitled "A Darwinian View of Life", it is just that, with a bonus philosophical tint. Feeding on the ideas of Professor Dawkins's previous books ("The Selfish Gene", "The Extended Phenotype" and "The Blind Watchmaker"), this is a short volume, albeit dense in themes and thought-provoking, unlikely to allow you to easily let go of it until you have finished reading.
The first chapter, "The Digital River", rests atop the river metaphor. Starting with the obvious remark that every living organism is sure to have had an unbroken line of successful ancestors (i.e. ancestors that did not die before having at least one offspring that survived them), the author proceeds to explain that "It is not success that makes good genes. It is good genes that make success, and nothing an individual does during its lifetime has any effect whatever upon its genes". Thus the river of the title is "a river of DNA" that "flows through time, not space. It is a river of information, not a river of bones and tissues: a river of abstract instructions for building bodies, not a river of solid bodies themselves". Admirably sticking to this metaphor, Dawkins explains descent, heredity and speciation in this easy to comprehend style, turning later on to the differences between analog and digital transmission and showing why the DNA code can be regarded as digital information that gets passed down the generations.
In the second chapter, "All Africa and Her Progenies", the reader is introduced in the same non-technical manner to the concept of mitochondrial DNA - the DNA that is found in little cell organelles called 'mitochondria'. It is not reshuffled the way that nuclear DNA is at the moment of reproductive cells formation and can only be transmitted to children through the female line (since only the female egg is large enough to contain mitochondria that can divide and get passed down to the cells of the forming embryo). Thus, apart from the DNA found in the nuclei of every cell, there is this second line of descent, the mitochondrial DNA, tracing each individual's ancestry back to Africa, to a remote female ancestor poetically called "Mitochondrial Eve".
The third chapter, "Do Good by Stealth", uses many examples from nature to show how relative "perception" and behavioral patterns are across the living world. A few interesting experiments are described, along with their conclusions. For instance, for black-headed gulls, "a threatening neighbor is little more than a disembodied black face. No body, or wings, or anything else seem to be necessary". Turkey mothers attack anything that moves in order to protect their chicks, except for moving things that emit the sounds made by baby turkeys; alas, a deaf turkey mother killed its own offspring because even though they looked and moved like baby turkeys, it made no difference for the mother bird's perception, since all she relied upon was the hearing sense (which she lacked). Professor Dawkins then moves on to show the fallacy of the argument from personal incredulity and suggests along the lines a method of approach that can be employed to explain how "a device that must [seemingly] be perfect if it is to work at all" could evolve. The bottom line of the chapter is "Do good by stealth. A key feature of evolution is its gradualness. This is a matter of principle rather than fact. (...) Without gradualness in these cases, we are back to miracle, which is simply a synonym for the total absence of explanation."
The fourth chapter, "God's Utility Function", introduces the concepts of "reverse engineering" and "utility function" (the latter being the economical term describing "that which is maximized"). Applying these concepts to a few cases, such as the elaborate dance of bees, used to indicate the relative source and distance of food, the sex ratio in elephant seal populations and the evolutionary arms race between cheetahs and gazelles, this chapter also provides food for thought, showing that "We humans have purpose on the brain. We find it hard to look at anything without wondering what is it 'for', what the motive for it is, or the purpose behind it. When the obsession with purpose becomes pathological it is called paranoia - reading malevolent purpose for what is actually random bad luck. But this is just an exaggerated form of a nearly universal delusion. Show us almost any object or process, and it is hard for us to resist the 'Why' question - the 'What is it for?' question."
The book's fifth and final chapter, "The Replication Bomb", uses the supernova analogy to illustrate the many levels that need to be achieved by intelligent life forms that find themselves in this universe, taking note of it and starting to explore it, in search of other intelligent life. The first step in this process is "the Replicator Threshold itself: the arising of some kind of self-copying system in which there is at least a rudimentary form of hereditary variation, with occasional random mistakes in copying". Then a phenotype threshold will be needed, a replicator team one, a multi-cellular organism one, the high-speed information processing level, consciousness, language, cooperative technology, radio and finally space travel. The logical unfolding of this model is a very interesting read.
To conclude, I find "River Out of Eden" to be excellent for somebody having never read anything else by Richard Dawkins, but I urge you to buy and read this book even if you have read some of his other works. It is surprisingly inspirational (and even poetic, some might argue), while not burdening the reader with technicalities in the least. This book made it clear for me that Professor Dawkins's prose is an exquisite craft, indeed.
Having read all of Richard Dawkins and been a regular attender at his lectures, I came to this book through an audio version read by him; doing a lot of travelling at one time, I whiled away the miles by listening to CDs and tapes. This was a present from someone who knew me well and I enjoyed the listening for many miles.
"Whether Mitochondrial Eve was an African or not, it is important to avoid a possible confusion with another sense in which it is undoubtedly true our ancestors came out of Africa. Mitochondrial Eve is a recent ancestor of all human beings." (Pp. 60-61)
From the artificial woodland floor of the Oxford Museum, the dance floor of the honey bee, the Bronze Age African rift valley to the clinical research laboratories throughout the world, Dawkins takes readers on a challenging, intellectual journey exploring our pasts, presents and futures with all the enthusiasm and energy of an H.G. Wells explorer. He wants to discover rational, scientifically explicable answers to the most basic of questions.
Throughout the book, he quotes extensively and, surprisingly, many of these quotations are from poets - Wordsworth, Housman, even Genesis. This explains why he has been awarded as many arts prizes for his writing as science prizes for his content.
" ... there is, at bottom, no design, no bottom, no purpose, no evil and no good, nothing but blind, pitiless indifference. As that unhappy poet A.E. Housman put it:
"For Nature, heartless, witless Nature / Will neither care nor know".
DNA neither cares nor knows. DNA just is. And we dance to its tune." (P. 155)
The scientist in Dawkins might object to Housman's capital "N" as he anthropomorphized nature, but the poet in him would see the reflected awesome wonder it has had for humankind throughout its history. Dawkins' quotation might be misunderstood by some people (and certainly has been) and make others fearful in its starkness. I recommend that the book should be read through to gain invaluable insights into humanity.
on 12 April 2008
Eyes have evolved between 40 and 60 times in inveterbrates showing nine different distinctive characteristics. Hold on a second! How? Answer: evolution through natural selection. Thank you Mr. Darwin!
There two components to evolution - the central understanding of biology and zoology.
1. Random mutation of DNA during reproduction
2. Natural selection of genes.
When a species is separated by geographical barries (rivers, mountains) for a long period of time, the changes in group 1 will eventually be no longer compatable with group 2. They can't interbred and you then have two species where once their was one. That's why red squirrels can't interbred with grey ones.
Now, from simple DNA copying mechanisms in bacteria, all animals, plants, protozoa, fungi have evolved. How do we know this? We have an infinite amount of DNA analysis and about a billion fossils.
Some of the key concepts in evolution are explained in this book. DNA being the instruction set for a living organism, the actual structure of DNA itself, the fact that all humans share a common female ancestor (in the female - female line) whose time on the planet can be estimated by mathematically analysing the michondrial DNA differences and factoring them with mutations rates.
In this book, we are also treated to some interesting anecdotes from the animal kingdom:
1. Gray squirrels and Req squirrels can't interbred because they have evolved into separate spieces.
2. Turkeys kill anything that moves near their babies unless it emits a babies cry. If they are deaf they can kill their own babies because they use the babies cry to differentiate between their babies and other moving objects such as rats, mice etc.
3. Honeybees tell each other the whereabouts of flowers by means of a carefully coded dance.
All along the central theme of natural selection is referenced and explained. Whatever works best, reproduces best. The best genes stay in the gene pool while the worst are chucked out by an amoral and unconcious natural selection process.
Dawkins has written several books on evolution. So what's so good about this one? I have read several of them. They all have a lucid, succint style and are written with Dawkins' infectious enthusasim. This one is shorter the others. So if you want the good grounding in evolution but are not worried about every nook and cranny of what forms the central understanding of zoology and biology. Go for this book.