Evolution - Beyond the Popular Science
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.
As an example closer to home take a look at common dogs. I can bet that some biologist in the far future (say 100 million years from now) is going to find all of these dog fossils, especially in pet cemetaries, etc. and conclude that these were all different species of animal. A chihauhau vs a Saint Bernard? the same species? come on now.... ;-)
This loose grey zone is probably part of the problem. and I can see them trying desperately trying to find the intermediate forms in the fossil record. They will have just "mysteriously appeared"
"It is a greater offense to steal men's labor, than their clothes"
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.
Read Bujold. Free (as in
True, they are both theories, however, evolution has literally tons of experimental evidence behind it, whereas creationism (by this I mean "scientific creationism" - as in a young earth) has none (and in fact, plenty of evidence which just plain doens't fit with it.
Therefore, in a scientific sense, evolution is by far the strongest theory.
Warning: Some ideologies on the Net are smaller than they appear.
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.
XML causes global warming.
The concepts of "microevolution" and "macroevolution" are basically arbitrary distinctions invented by people who are forced to admit that biological evolution does, in fact, happen, but cannot accept that twin-nested hierarchies of evolutionary common descent are the source of the biodiversity on Earth.
Let me give you an example. If I stand on one side of my living room and take tiny toe-to-heel steps, I will reach the other side of my living room within a minute or so. If I stand on one edge of my town and do the same thing, I'll reach the other side in a day or so. If I stand in New York and do the same thing, I'll reach Los Angeles in a few hundred years (just a guess, really.)
The point is this: in each of the three examples, the results are increasingly visible and dramatic, but the process is exactly the same. You would not, I presume, suggest that I was "micro-walking" in my living room and "macro-walking" across America. Some people seem to think that evolution is some sort of directed Black Magik. It's not. Biological evolution is variation in the gene pool of a population over time. That's it. That's all it is. The fact that its results are more visible and dramatic over time should not be particularly surprising to anybody.
We're going down, in a spiral to the ground
Without god, there are no moral absolutes, goes the argument. And without moral absolutes, why, what's to prevent all sorts of immorality?
Therefore, attempts to debate the theory of evolution with "christian" fundamentalists, or their fellow travelers, is pointless, because you are challenging their entire world view, not objectively evaluating competing scientific theories.
FWIW, almost all thinking non-fundamentalist Christians, as do most educated people regardless of religious belief/nonbelief, realize evolution is a scientific reality.
And we, the vast majority, further realize that evolution doesn't imply anything about morality, or the existence of god, one way or the other.
And therefore there is no reason to waste time in high school science classes teaching theories like creationism that are neither theologically nor scientifically interesting.
The concept of a species is an artificial classification scheme imposed upon a continuous reality. Therefore saying when a "speciation" occurs is entirely a matter of opinion. That said, there are plenty of examples of so-called macroevolution in the fossil record (hell, the entire fossil record is one big macroevolutionary record!); you have only to open your eyes and see it.
Evolution is a fact. Things change.
The "theory of evolution of biological species by natural selection" is a scientific theory to explain the observed variation and "relatedness" of biological organisms, and their change through time as observed in the fossil record.
The "theory" of creationism is a load of pseudo-scientific mumbo-jumbo used to prop up some people's faith in the Almighty in the face of evidence that contradicts the primary literary source of their belief.
Ergo, stating the belief that the theory of evolution and the theory of creationism are both scientific theories of equal merit demonstrates a profound lack of understanding of science and its rigid reliance on fact and observation. Q.E.D.
Liberal (adj.): Free from bigotry; open to progress; tolerant of others.
For all you fools out there who think evolution is a proven fact, please read a book called Not By Chance! by Lee Spetner, an information theorist from MIT who has studied evolution on the side since the 1960's. 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).
On second thought, don't bother. Your mind is made up and you wouldn't want to be confused with the facts. And Spetner offers no religious alternative, so you cannot attack him as a religious fanatic, so what strawman argument will you fall back on instead?
Just for the record, I do not personally believe in "creation science", nor do I think that science can explain how "creation" occurred, but I am amazed at how completely fooled Slashdot readers are by the completely discredited neo-Darwinian theory of evolution. If Darwin were here, I think he'd slap you all upside the head.
RussP.org
I watch Brit Hume on Fox News
OK, I'll take the troll bait....
I don't think you (or most people) really understand what evolution is. It's not one species suddenly becoming another, like monkeys turning into people, or a thing that happened once or twice in the distant past. It is a continous process of change, small or large, that is happening now. The example you cited about the dogs is actually an excellent example of biological evolution, even though the evolution in this case is artificially accelerated and forced down certain paths by man. Evolution is also happening right under your skin, as we speak. Our immune system is constatnly spawning new species (yes, species) of antibodies to fight foreign invaders. We end up with millions of species of antibodies by the time we die.
No, it is indeed called the theory of evolution, but gravity is also called the theory of gravity. ( So you shouldn't mind if I throw you from the roof of my building. You'll have about 4 or 5 seconds to fold your arms and explain how gravity is just a theory before you become part of the pavement on Market Street.) Don't confuse "theory" with "unproven idea". In fact, the scientific definiton of theory is nearly the opposite of "unproven idea". A theory, according to Dictionary.com is "[a] set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena." I would say Creationism hardly falls under that classification.
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.
What you are equating evolution with is a hypothesis, not a theory, and the two are very different. Or, put another way,
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.
The Future of Human Evolution: Autonomy
That is kinda strange as all religions believe in creationism. However, people of most other religions seem to realize the distinction between faith-based religious beliefs and scientific facts like evolution. Also, this debate seems to be the hottest in America alone. Why is that?
I don't want to hurt anyone's sensibilities, but history is filled with instances of the Christian church condemning the scientific world and trying to regulate what the scientists say.
I am interested in knowing the views of all you calm people out there as to why evolution is so vigorously attacked by America's religious Christians alone and not so much by other religions/countries?
All your favorite sites in one place!
I hate to intrude into the creationism vs. evolution debates which seem to be dominating this discussion, but I actually have a _different_ question. We all know that high school and perhaps introductory college texts on general biology have often become seriously watered down and error-ridden. Stephen Jay Gould wrote one amusing essay on how a particular error (something to do with _Eohippus_, which isn't named _Eohippus_ anymore I guess, but I like the old name) has propagated itself, unchecked, from text to text.
Frankly I don't trust many high school or freshman level textbooks in _any_ subject. So I'd like to know: can anyone recommend a scholarly, well-referenced textbook, aimed about about the twelfth-grade level, in biology, in particular one which does a good job of covering evolution? Any particular authors and titles stand out? Any good resources to reviews and critiques of popular science textbooks?
The popular works have their place, but they're all deficient in some way. Gould is too scattershot--he's an essayist, really--and Dawkins is too polemical (frankly I think Dawkins has become an unmitigated jackass in recent years, and I'm not a creationist.)
hyacinthus.