Evolution - Beyond the Popular Science

ny writes: "Patterns and Processes of Vertebrate Evolution is not popular science, but as a broad overview of the processes of evolutionary change it is reasonably accessible to non-specialists. I recommend it to anyone who has read Gould and Dawkins and Ridley and so forth and now wants something more substantial." This sounds like a book to interest anyone interested in current ideas in evolution -- read on below for Danny's complete review. Patterns and Processes of Vertebrate Evolution author Robert L. Carroll pages 448 publisher Cambridge University Press rating 9 reviewer Danny Yee ISBN 0-521-47809-X summary An uncompromising but accessable overview of modern evolutionary theory.

In Patterns and Processes of Vertebrate Evolution Carroll undertook an ambitious project - nothing less than to update George Gaylord Simpson's classic works from the 1940s and 50s, Tempo and Mode in Evolution and The Major Features of Evolution. The result is a "broad picture" overview of the processes of evolutionary change, centred on paleontology but attempting to integrate that with the rest of biology. Patterns and Processes is aimed at students of paleontology and specialists in that and related fields, but it should also be considered by general readers: while it goes into quite involved details, they are always used to illustrate broader ideas and there is solid motivation for persevering with them. It is especially recommended to those unhappy with the lack of substance in popular debates over the theory of punctuated equilibrium, which Carroll critically appraises. Patterns and Processes is effectively illustrated with line-drawings and figures and has a useful glossary.

Carroll begins with an overview of current problems in evolutionary theory and in particular of the "gap" between short- and long-term processes in evolution, and between paleontology and other disciplines. He also discusses the choice of the vertebrates as a testing ground (which is picked up at the end of the book in a brief comparison with invertebrate metazoa, prokaryotes, protists, and vascular plants). He then provides an overview of theories of evolution, at the level of populations and species, from Darwin through Dobzhansky and Mayr to Gould and Eldredge.

Two chapters present some essential background. The first looks at evolution in modern populations, in particular at rates of evolution among the Galapagos island finches, where significant directional change does occur and doesn't appear to be correlated with speciation. The second considers some of the limitations of fossil evidence, the irregularity of fossilization and other stratigraphic issues and problems with the dating of events and processes and the measurement of rates of evolution.

Next come two case studies. The rates and directions of change among late Cenozoic mammals are examined with an eye to testing theories of punctuated equilibrium and species selection. Many lineages exhibit stasis "of particular characters and character complexes," but in none is there stasis of all characters and phyletic evolution is common. And "no major trends involving a complex of character changes can be demonstrated as having resulted from species selection." In contrast, the rapid radiation of the cichlid fish of the East African Great Lakes provides some evidence for species level evolution, and a bridge between macroevolution and microevolution.

Four separate chapters focus on related disciplines, in an attempt to reunify different fields. Taxonomy influences our basic concepts of evolutionary patterns as well as providing tools for discovering them; phylogenetic systematics (cladistics) has been particular influential, offering "an objective way to compare patterns of large-scale evolution from group to group and within groups over time" and forcing reconsideration of traditional naming schemes in the vertebrates. With evolutionary genetics Carroll presents some basic models, focusing on quantitative traits; he touches on the enigma of low selection coefficients and on genetic constraints.

Turning to developmental biology, Carroll surveys heterochrony, homeobox and Hox genes, and the phylotypic stage. He then applies this to the origin of craniates and skull and axial skeleton development, but above all to tetrapod limbs, to their origins, developmental processes, morphogenesis, and evolution. He also considers the integration of developmental biology with the evolutionary synthesis and its possible connections with macroevolution. Other constraints are imposed by physics: Carroll considers vertebrate locomotion in water, in the air, and on land, and touches on membrane transport, heat transfer, and size scaling.

Three chapters then look at large scale structure and patterns in evolution. A chapter on "major transitions" focuses on movements between environments: the most detailed study is of the origin of birds, but others cover the origins of terrestrial vertebrates, mosasaurs, and whales. Critical periods saw rates of change exceeding those in ancestral and descendant groups, but not those observed in modern populations; more importantly, directions of change were sustained for long periods. Turning to radiations, Carroll treats at length the Cambrian explosion and the radiation of early Cenozoic mammals: occurring in intervals of 10 million years or less; these differ from other, slower radiations into already occupied environments and "can certainly be attributed to factors that were not considered by Darwin". At the largest scales, vertebrate evolution has been irregular, driven by "forces" that can't be extrapolated from those operating at the level of populations and species: among them sustained evolutionary trends, continental drift, and mass extinctions.

Among Carroll's overall conclusions:

"Evolutionary forces that can be studied in modern populations are sufficiently powerful to account for the amount and rate of morphological change throughout the entire course of vertebrate history."

and

"Transitions between environments governed by major differences in physical constraints do not necessarily require special evolutionary processes."

but at the same time

"Large-scale patterns of evolution cannot be fully explained by processes that are directly observable at the level of modern populations and species.

... the patterns, rates, and controlling forces of evolution are much more varied than had been conceived by either Darwin or Simpson."

And macroevolution is essentially historical, with each major event "unique and worthy of detailed study in its own right".

Patterns and Processes in Vertebrate Evolution combines clear exposition of details - and what appears to be an encyclopedic knowledge of vertebrate history - with a willingness to tackle big questions. Sometimes Carroll seems to take both sides of debates, but that is a reflection of respect for complexity, not of unengaged fence-sitting. The result is a useful overview for students or outsiders; it also seems to have established itself as a minor classic within the field.

You might want to purchase Patterns and Processes in Vertebrate Evolution from bn.com or read some of Danny's other evolution book reviews. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.

Comments

Re:Define order, Define disorder

[Fiver-rah]

perhaps someone should attempt to define order or disorder, without being circular in their definitions.

Someone did. His name was Boltzmann. The more ordered a system is, the fewer microstates available to it. What does that mean? Well, a macroscopic example is this: imagine you have a bunch of books you're putting on a shelf. There's only one way to put the books alphabetically (assuming you have no duplicate copies). But there's a really large number of ways to put them on if you put them every which way. So let's compare the order of two systems. Our first system is our books on the shelf, restricted to alphabetical ordering. The second is our books on the shelf. The first system has only one way it can be arranged; the second (assuming we have more than one book) has more. So the first system is more ordered.

This is a little simplistic, but it gets the point across.

Trust me, entropy really is a well-defined concept. Or don't trust me; read for yourself.

Re:All things considered

[scotch]

Please. You make it sound like creationism and evolution are on equal scientific footing. This is simply not true. There is a mountain of evidence that supports evolution. For creationism, there is hardly even any definitive statement of what the "theory of creationism" is. Most evidence creationists cite is actually supposed evidence against evolution, not support for creationism. Just check the web - there are dozens of bad arguments out there - once they are introduced, they never die, arm chair "creation scientists" keep repeating them. My favorites are the onces involving the moon recession rates and the amount of dust on the moon - real gems.

Calling evolution a religion is either dishonest or an exercise in destroying the meaning of "religion" and making the word so vague that you can call anything a religion. Take your pick.

Theory != Some vague possibility

[FreeUser]

I know it's nitpicky but evolution is a scientific "possibility". It is still regarded as a theory after all.

All things short of a methematical 'proof' in science is theory, including gravitation and even cause-and-effect itself. The word 'theory' in science has an entirely different connotation to what it has in common parlence, and in particular to the way you use it here.

In the American vernacular, "theory" often means "imperfect fact" - part of a hierarchy of confidence running downhill from fact to theory to hypothesis to guess.

Well evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. And humans evolved from ape-like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered.

In science "fact" can only mean "confirmed to such a degree that it would be perverse to withhold provisional consent." I suppose that apples might start to rise tomorrow, but the possibility does not merit equal time in physics classrooms.

Evolutionists have been very clear about this distinction of fact and theory from the very beginning, if only because we have always acknowledged how far we are from completely understanding the mechanisms (theory) by which evolution (fact) occurred.

-- Stephen J. Gould, "Evolution as Fact and Theory"; Discover, May 1981

What you are equating evolution with is a hypothesis, not a theory, and the two are very different. Or, put another way,

A few words need to be said about the "theory of evolution," which most people take to mean the proposition that organisms have evolved from common ancestors. In everyday speech, "theory" often means a hypothesis or even a mere speculation. But in science, "theory" means "a statement of what are held to be the general laws, principles, or causes of something known or observed", as the Oxford English Dictionary defines it.
[-- Douglas J. Futuyma]

The theory is not did evolution happen. We already know evolution did and does happen, there is a mountain of factual data underscoring that point. What is theoretical and debated (by scientists) is what the mechanism is by which primates became human and dinasaurs became birds. The fact that it happened is denied only by those with a religious agenda, whose fragile beliefs are challenged by the factual data collected by thousands of researches all over the face of the planet.

And I know this non-fundamental Christian believes God could have used evolution to create us.

And I know this Athiest believes aliens could have seeded the Earth with proto-human life, but until I see some sensible evidence indicating that such might be the case, I'm not going to pay the notion much heed.

Re:read Not By Chance!

[tgibbs]

He proves rigorously that Neo-Carwinian evolution could not have happened -- or rather is about as unlikely as tossing 10,000,000 coins at random and having them all come up heads (yes, that is "possible", I guess).

Let's say I toss 10,000,000 coins, and make a careful record of the sequence of heads and tails. Now, I calculate the probability of that exact sequence, and discover that it is exactly as low as the probability of having them all come up heads. Have I proved that the coins are weighted? Or influenced by God? No, because every sequence of coins has exactly the same very low probability, but nevertheless one of them has to come up. This is the falacy of calcuating probabilities backwards. Every attempt I've seen to calculate the probability of evolution falls into that same basic error.

Remember, also, that natural selection is not a random process, even though it has random elements. For example, it is possible to use an evolutionary simulation to solve an equation, even when there is only one possible solution--and it is far more efficient than trying to guess the answer randomly.

Re:Why Fundamentalist "Christians" Care

[Tyrone Slothrop]

"What bothers me most as a Christian is that the theory of evolution is presented as fact"

Nonsense.

What bothers you most as a christian is that you believe that somehow evolution implies something about the truth of your beliefs. Otherwise, it's such an esoteric and complicated theory you wouldn't waste your time coming up with examples.

For example, it is rare indeed to see a statement such as "what bothers me as a christian about the infectious theory of disease is..." or "what bothers me as a christian about the theory of musical harmony.."

Just like disease theories and musical theories, evolution implies nothing about either your religion or about how to behave and discussing the theories is totally irrelevant.

Therefore, attempts to argue the truth of evolution with someone arguing "as a christian" is pointless. Again, it has nothing whatsoever to do with christianity as most people understand the religion.

However, what IS germane is to point out, over and over again, is that the argument for creationism is really about the effort to force a particular, and IMO very ugly, moral agenda into public schools. An agenda which, again, squares not at all with the moral agenda of most practicing religious people.