on October 13, 2006
Richard Dawkins wrote a very enjoyable book titled The Ancestors Tale. It traces our evolution backwards, from humans, through apes and monkeys and so on, back to simple one-celled organisms. It tells the who of evolution: which species were descended from which. The Making of the Fittest tells the how and why: how variations appear in organisms and why they survive, or don't. This is the story of natural selection. Darwin told the story, but a lot more has been learned since then, especially in recent decades, and Sean B. Carroll has been one of the discoverers. But, unlike many researchers, he can write a readable book for beginners.
Carroll focuses on DNA because that's of prime importance. When DNA is copied, for the reproduction of the cell or the organism, the copy is not always exact. The new variant is usually harmful, but might be helpful. Carroll shows, using elementary arithmetic, why helpful variants occur and prosper much more often that most people would guess. Keep in mind that, when a bad gene does come along, the organism usually dies and the gene disappears from the pool. The good genes usually accumulate.
Carroll tells the story mostly through examples. For example, we humans are descended from animals that could see only 2 colors. Carroll tells of the duplication of the gene for one of the colors and the mutation of the second copy to react to a third color. (I simplify; Carroll tells more of the story.) Duplication and subsequent mutation of genes is very important in evolution. It allows organisms to develop new capabilities without losing the old.
Another important mechanism involves genes which control the expression of other genes. Even with no change in a given gene, a change that causes the gene to be expressed in a new place or at an additional stage in development can give rise to a new capability with no harm to the old. (Again I simplify.)
Gene duplication, changes in gene expression, and other mutations leave traces in our DNA and these give clues to our ancestry. This fact explains the book's subtitle. More important to Carroll, these traces also demonstrate natural selection at work. To give a personal example, an examination of my genome would show that the gene which shuts off lactose digestion in adults had been knocked out by mutation; as a result, I have a source of nutrition that is not available to most humans.
There's not much that one has to know to read this book. It probably helps to know that a gene is a segment of DNA and that the sequence of its bases determines the sequence of amino acids that makes up a protein. However, Carroll explains this. I haven't been a beginner for a few decades now, but I think Making of the Fittest will be accessible to a bright high-school.
As elementary as it is, it still has information that is of interest to me. The most important concerns the evolution or the eye. (He doesn't indicate the value of a cup-shaped eye: the animal can tell the direction from which the light comes by the part of the eye which isn't receiving it. And an eye that has only a small opening can form a rough image even without a lens.)
Carroll says a lot about disproving creationist arguments. This is probably futile. Most creationists are convinced that they have a Higher Truth revealed to them by God Himself. This book will, however, be useful for people who accept creationism simply because they don't know the science. And, of course, for beginners who are simply interested in the science.
For those who are interested in the material in this book and would like more information, there are a few books, ranging from elementary to advanced, which I recommend and which I have reviewed. Two are by Sean Carroll himself, on the topic of "evolutionary developmental biology; one (Endless Forms Most Beautiful) is excellent for those who have absorbed the material in Making of the Fittest and the other (From DNA to Diversity) is considerably more technical. Other books cover different related material. Click on "See all my reviews", above for the reviews. (There are 3 pages of them.) Or, to see only books related to evolution, click on my name and, on the profile page, click on the Listmania "Natural Processes That Promote Evolution".
There is a notorious book for creationists titled _Evolution: The Fossils Say No!_ It gets right to its point in its title which accomplishes two things. One is to claim that fossils do not say what overwhelmingly biologists and geologists say they say. The other is to emphasize that fossils are the chief evidence evolution can muster. That might have been true a hundred years ago, but now, even if we had no fossils to study, we would still have wonderfully abundant evidence of evolution happening and just how it happened. We can now look directly at the DNA in animals that have evolved from previous ancestors and see indubitable chains of linkage. Sean B. Carroll, a professor of genetics, relates the stories scientists are coaxing from the molecules of genes in _The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution_ (Norton). He points out in his preface that there is wide public acceptance and understanding of DNA testing in solving crimes; DNA can provide testimony about who was present at a crime scene with far more trustworthiness than fingerprints or eyewitness recollection. Yet polls consistently show that something like half of the public in the United States are more likely to go with the anti-Darwinian ideas in _Evolution: The Fossils Say No!_ than they are to subscribe to the theory of evolution. It is Carroll's aim to have readers consider the DNA evidence for evolution as strong as DNA evidence from crime scenes, and his clear and entertaining book does just that. "Every evolutionary change between species, from physical form to digestive metabolism," he writes, "is due to - and recorded in - DNA. So, too, is the 'paternity' of species. DNA contains, therefore, the ultimate forensic record of evolution." Carroll's book gives plenty of fascinating instances of evidence for that DNA record.
He starts with a fish that has no red blood cells. Before it was found, biologists taught that all vertebrates had red blood cells containing the hemoglobin that carries oxygen, and when there were stories of fish without blood in the Antarctic, they were assumed to be just stories. But in 1954, biologists were amazed to read a report of the icefish, so called because it looks transparent; it has no red blood cells to block the light. There is no fossil record for these fishes, but the DNA is there, although it could only tell the story of the icefish's evolution forty years after their blood was first sampled. The DNA that codes for red blood cells in fish and the rest of us is there, but only partially, and in an eroded form that cannot work. One of the lessons Carroll consistently draws is that in evolution, there is a "use it or lose it" dictum. Genes change, even if mutation rates are low; if the change is deleterious, it might be that the organism is sufficiently wounded that it gets no chance to pass the gene on. It also might be that other genes make up for the change, and if so, the changed gene gets passed to the next generation, but since it does not work, it can further decay as it is passed further down. In this fashion, natural selection maintains working genes, and ignores inoperative ones. The icefish DNA for hemoglobin is eroded, but it is still there from the time of its ancestors that had hemoglobin. (This is a perfect argument against some supernatural designer building the fish in this way: what would be the point of including eroded, nonfunctional DNA?) It does not do anything but get copied, perhaps imperfectly, for succeeding generations; the icefish has made other changes to do without hemoglobin, using a blood that is literally ice water, a large volume of it pumped by a large heart, to take advantage of the high solubility of the oxygen in icy waters. Carroll gives plenty of other fascinating examples of tracking evolution in this way.
Carroll gives an excellent but simple explanation of the mathematics of evolution, showing that while most mutations are, as the creationists remind us, harmful, that does not preclude a tiny fraction from being helpful, and the odds of this tiny fraction occurring in large populations over millions of years is quite formidable. In discussing why people may rely on irrational or non-scientific explanations, he turns to the example of Trofim Lysenko, whose unscientific and yet state-sponsored ideas of inheritance nullified for years any biological advancement within the Soviet Union. He also finds that the tactics of chiropractors in opposition to vaccination (such as exaggerating disagreements between scientists) are the same as creationists use in opposition to evolution. Science works, and it does not become iffy just because it turns its attention to a branch of nature that has implications against literal interpretation of scriptures. Carroll makes plain that such a religious expert as Pope John Paul II accepted evolution as science (although there has been some Catholic backlash in the past year); clearly there are some Christians who do not see evolution as a threat. In a final chapter, he makes clear that this is not just a matter of whether or not we teach evolution in the schools, for looking at problems like overfishing or the biological effects of global warming can only be understood in evolutionary terms, unimpeded by religious or governmental authority. It may be too much to ask that those who get their biology and history from religious authorities will read Carroll and understand how overwhelming (and beautiful) is the new evidence for evolution, but he has given an excellent summary for all to try.
This is a solid but unexceptional popularization aimed at educating readers about how modern DNA sequencing - molecular methods have helped to explain the basis for adaptive changes and support evolutionary theory. Carroll produces a series of well written and illustrated chapters illustrating the fundamental genetic basis for adaptive changes. In doing so, he shows how this data vindicates and fleshes out basic features of evolutionary theory. This is done quite well but the book suffers from some significant defects. The last 3 chapters are largely tangential to the main thrust of the book. One is about the genesis of complex organs and developmental programs. This is ground that Carroll covered very well in his book Endless Forms Most Beautiful. This chapter is very good but doesn't add much to what he has written previously. Another later chapter is an analysis of the anti-evolution movement. This is solid essay but tangential to the topic of the book and the last chapter is a well written plea for more rational conservation and development measures to protect non-human species. I agree wholeheartedly with all Carroll writes on this subject but its not really an organic part of the book.
More important, Carroll has not addressed 2 important areas where some further discussion of molecular evidence would he very important. One is the use of sequencing data to generate phylogenetic trees and in general the whole crucial topic of molecular data as providing evidence for the unity of life is dealt with superficially. Most of Carroll's discussions are examples of within species evolution (microevolution); he doesn't address speciation (macroevolution). But many critics of evolution concede the existence of microevolution but dispute the reality of speciation. Carroll's omission of this topic is a major hole.
It's a sad commentary that any book on biology published in the US must devote pages and ink to refuting the rants of "anti-Darwinists" in that nation. Richard Dawkins ["The Selfish Gene"] holds a chair at promoting "Public Understanding of Science" at Oxford. Carroll, whose role as a professor of genetics provides firm underpinning, is establishing himself in a similar niche in the US. This book is an example of how well he can fulfill that undertaking. In his previous work "Endless Forms Most Beautiful", Carroll described some of the manifestations of the genome's activities. In this book he delves more into today's operations within the genome and how those were derived from the distant past.
The author's selection of examples to explain DNA's role in life may seem bizarre at first glance: "icefish" carrying "anti-freeze" in their bodies, what humble pigeons tell us about life, and what human skin colour really means. Each of his examples carries an historical record of how they came to be that way. Evolution, he reminds us, builds upon what went before. Once a trait, no matter how "primitive", is established, mutation may improve its possibility of success down the generations. "Primitive", by the way, is a term Carroll shuns, since those traits that survive are clearly best suited for that organism in that time and place. It's important to understand that, since a good many health issues relying on genetic research must be considered in the light of environmental conditions. Infectious organisms change to cope with treatment and medicines must be developed to cope with their adaptations. This is the record of life, with the earliest genes bifurcating to form new traits with the passage of time and new conditions.
Carroll's chapters address a number of life's little quirks. There's a discussion of how populations shift and divide when conditions change [stickleback fish], an account of the discovery and significance of "thermophilic" microbes found in Yellowstone Park hot springs, and how Soviet politics dabbled in science to virtually destroy agriculture in the communist empire. Every chapter contributes to learning how genetics works and why some understanding of the processes involved is important. For this reviewer, however, the author's presentation of the historical beginnings and development of eyes remains the most fascinating. Although Darwin was greatly disturbed that he couldn't conceive how eyes could have evolved, modern research has determined the process. In Carroll's hands, the mechanism producing eyes is clearly revealed and almost exquisitely explained. He shows how light perception across various species provides clues to past ocular structures. Once you have read this section, you will never be able to consider "the" eye [which is too often presumed to be human] in the same way again.
The book's close, which Carroll clearly feels necessary, is somewhat depressing. Evolution shouldn't need defending - it's clearly how life works. The author has the good sense to apply practical logic in itsdefence, using the issues of over-hunting and -fishing to show how humans indifferent or hostile to the concept of life changing over time are driving evolution themselves. He deems the result of that indifference "Unnatural Selection" since it is driving down the size and adaptability of more than one species. There are plausible arguments for starting this book with the final chapter. No matter where started, however, this is a book to be read. [stephen a. haines - Ottawa, Canada]
on August 4, 2007
I found this book very gripping and approachable. For the most part Carroll focuses on just a few sets of genes involved in the development and function of the eye, hemoglobin, and color. He then weaves these throughout the text bringing each up in different contexts as he discusses fossil genes (a favorite section of mine), immortal genes, convergent evolution, and production of new genes. This focuses the book and allows a deeper appreciation for the subject matter.
Make no mistake, Carroll is ardently arguing the case for evolution as well. It is hard to understand how any educated person can continue to ignore the mountains of evidence of evolution and natural selection (these are separate facts!) and fall back on arguments that are in essence 200 years old. This is what ID is. Carroll is clearly agitated by this and remarks on how much of the methodology and science that verify natural selection and evolution are accepted in medicine and forensics, but somehow creationists pass on the core concepts themselves. The last two chapters are more philosophical in discussing first the denial of scientific findings (using refreshing examples I had not seen in this context before: Lysenko and chiropractics), then our responsibilities to our environment. I enjoyed this denouement as well.
Truly an exceptional book. I would highly recommend it to readers who have previously devoured the likes of Gould and Dawkins because this will give you a very different take on the field today. I would also suggest it to any evolution doubters who may have been bold enough to examine this page and this review. As a practicing biochemist and professor myself, I can assure you that Behe appears to have completely failed to understand basic findings in the fields of genetics and molecular biology on top of his confused understanding of evolution. Why, I do not know. Carroll is the real thing.
on March 7, 2007
One of the most attractive features of Sean Carroll's book is that although he makes many of the same points as one can find in other popular books on biology and evolution he illustrates them with refreshingly different examples. He begins by describing the icefish of Antarctica, a living contradiction of the standard idea that all vertebrates have red blood cells in their blood for transporting oxygen to their tissues: although these fish are clearly vertebrates, they lack the haemoglobin that would make their blood red. At the very low temperatures at which they live, oxygen is much more soluble in haemoglobin-free water than it is at higher temperatures, and they can manage perfectly well without haemoglobin or, in some species, myoglobin, the haemoglobin-like protein responsible for the red colour of many muscles. Not only do they do not need haemoglobin as much as other fish, they gain a positive advantage from not having it because their blood is far less viscous than it would be if it contained a high concentration of dissolved haemoglobin. On the other hand fish that live in very cold water need to avoid freezing solid, and icefish have solved this problem as well, by evolving anti-freeze proteins that prevent their tissues from freezing. All this sets the scene for Carroll to explain how studying the DNA of icefish allows the biochemist to understand what has happened to the haemoglobin that their warmer-living ancestors had, and where the anti-freeze proteins have come from. The globin genes are still there, and still recognizable, but no longer functional.
Later chapters discuss how mutations in DNA arise, and how these result in modifications to proteins, and from there to changes in function -- loss or modification of existing functions, such as colour vision and sensitivity to different odours, or the appearance of new ones. Humans, apes and most old-world monkeys have three-colour vision, for example, whereas most mammals have, at best, two-colour vision and are accordingly red-green colour-blind. On the other hand many birds and fish have four different colour receptors, and lampreys have five. Colour vision and olfactory sensitivity have tended to evolve in opposite directions: species that are mainly active in the day time tend to be strong in the former, and weak in the latter, and vice versa. Much of this is explained by the principle that functions that are not much used or not very necessary for survival tend to be lost, and one finds this illustrated in very diverse life forms. The bacteria responsible for tuberculosis and leprosy, for example, are closely related, but whereas one has retained nearly all of its ancestral genes in fully functional form, the other has lost a great many: being wholly parasitic, living only within host cells, it relies on its host for many biochemical functions that a free-living organism has to do for itself.
Where do new functions come from, and what happens to genes for functions that are lost? In both cases, as Carroll explains, genes become mutated: for new functions, such as the appearance of a new colour receptor, an existing and functional gene becomes duplicated, and then one of the two undergoes small modifications that allow it to code for a protein for a novel function; for an obsolete function there no natural selection to prevent the accumulation of harmful mutations, and eventually these render the gene incapable of coding for a functional protein. After describing many examples of how genetic information can be added or lost in the course of evolution Carroll devotes a chapter to a discussion of creationism, whose adherents sometimes claim that such transformations are impossible. This chapter is perhaps the best analysis currently available of the arguments used for creationism, both by their overtly religious supporters and also by their supposedly "scientific" fellow-travellers who promote the fantasy known as "intelligent design".
on October 21, 2006
This is the story of Natural Selection, presented in a compelling, easy to follow, and well researched manner proponents of Theological Creationism and/or Darwinism Evolution will appreciate, and perhaps move closer to the much needed reconciliatory position of Church and Scientist. Author Sean B. Carroll is very clever in presenting fundamental movements in the change and alteration of DNA in a way that hopefully not be rebuked or rebuffed by creationist: by studying genetic alterations by presenting changes that occurred in microbes and animals such as antactic fish, colobus monkeys, and dolphins, Carroll allows the reader to easily understand this very strong, fundamentally sound position of DNA related genetic based evolution. Carroll easily but thoroughly explains that the DNA of a specific gene directly related to a specific trait, when altered as a result of natural selection, changes the original structure of the gene itself. When genetic duplicating occurs, the structures are never quit 100% the same, and so, natural selection's alterations begin. If the variant change is not adaptable or is not capable of survival, then the gene fades away, allowing for additional variants to take hold and sustain itself.
In `The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution' by Sean B. Carroll readers interested in furthering their understanding regarding the rift between Creationism and Darwinism will find unquestionable scientific data that Carroll uses to support genetic enhanced Darwinism. Nevertheless, this is one good and fascinating read that all readers, regardless of your scientific background or not will really enjoy. For those of us interested in a more detailed understanding of Evolution, this is a must read. Well done.
on July 17, 2007
As Sean Carroll patiently explains, Charles Darwin did not theorize that evolution takes place; he didn't need to. Anyone who has ever bred puppies or guppies, hybridized orchids or corn, raised prize pigs or figs, has proven beyond argument that evolution happens.If all the evidence of evolution were imprinted on microchips and tossed in a pile, the pile would fill St. Peter's Cathedral to the dome. What Darwin theorized is how (and by implication why) evolution occurs--by random mutation, which he called "descent with modification", and natural selection by the criterion of reproductive success.
The Making of the Fittest clearly and coherently presents the evidence of modern genetic science that Darwin was basically correct. It's an easier book to read and comprehend that Carroll's previous masterpiece, Endless Forms Most Beautiful, and should be accessible to anyone with a good high school or middling college education. What a wise choice it would be for mandatory inclusion in all high school curricula, so that no child would really be left behind! In the long run, it's a more meaningful and effective book, and more humane, than Dawkins's God Delusion, since the religious fundamentalists are quite correct that evolution is incompatible with their kind of religion. Verily I say unto them, it's impossible to read this book and understand it, and still deny the role of evolution in the history of life.
on February 26, 2007
If the genetics revolution in biology is less well known to philosophers of science than the two great twentieth-century scientific revolutions in physics, it is only because unlike relativity theory and quantum theory, genetics has not occasioned any revolution in philosophy of science - the understanding of how science works. But the implications and possibilities of DNA may likely have greater significance for humanity than anything discovered in physics.
In this book Carroll cogently explains how DNA mutations produce the variety of alternatives given to natural selection in the evolutionary process. I was surprised to learn how important probability theory has become in microbiology.
He summarizes: "Given enough time identical or equivalent mutations will arise repeatedly by chance, and their fate (preservation or elimination) will be determined by the conditions of selection upon the traits they affect." (p. 155)
In the ninth chapter he levels his sights at past and current reactionaries including opponents to Pasteur's germ theory, Lysenko's suppresion of genetics in Stalin's Russia, American chiropractors' opposition to inoculation and vaccination, and the current "intelligent design" religious advocates' opposition to evolution.
In the concluding chapter Carroll's explanation of the effects of human intervention in evolution, e.g. overfishing, pollution, global warming, etc. is the "jarring gong" that signals destruction beyond recovery.
As a social scientist, I rely upon popularizers to keep me informed about developments in other sciences. And I found Carroll's book to be as informative as Brian Green's popularizing books on physics.
See my Twentieth-Century Philosophy of Science: A History web site at philsci with free downloads by chapter.
Thomas J. Hickey
on April 22, 2007
One of the most confusing evidences and rationals for evolution lies in the study of DNA sequences, yet it is also one of the most convincing and important.
In this book, Carroll lays out the DNA evidence for evolution, its mechanism, and its methods very well. In terms everyone can understand, he demonstrates the action of pressure working on chance mutations resulting in a fitness that may not be the best, but it's what is available.
Along the way, he tackles the arguments of the anti-evolution crowd quite handily, showing how accumulations in the DNA record show the changes over a species history. One of the things I really liked was his demonstration of the math of mutations, and how the idea of changes accumulating over large numbers in long times makes mathimatical sense.
My one small issue with this book is that it can be quite dry in places. The sheer repitition of evidence can be a bit numbing at times; but that is what made Darwin's Origin of the Species so convincing, and it works here, too.