Slashdot Mirror
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.
Yesterday I found out my boss is a devout 7-day creationist. I myself am an athiest, but I did not admit this to her for fear of my job :P Anyway we entered a heated discussion about the origins of the universe, and frankly I provided more evidence through the big bang theory and our information about human vs. ape genetics that she simply back into the "faith" arguement. This article will give me the fodder I need to lay her flat on her ass the next time discussion of such things comes up. Thanks slashdot!
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"
Evolution is always promoted as being founded on scientific facts that were collected by Darwin, and this was why it gradually gained acceptance in the universities, schools etc. This book demonstrates that it was promoted for many years before Darwin, his Origin of Species only appearing at the right time.
The ground work for the acceptance of evolution was laid by Charles Lyell in his Principles of Geology. He quickly befriended Darwin when he returned from the Beagle voyage and the circumstantial evidence is that it was he who suggested to Darwin he should write about evolution. Darwin had no thought of it before then.
Throughout the famous Beagle voyage, Darwin was far more interested in geology than biology. He did NOT think of evolution whilst visiting the Galapagos and seeing the various beaks of the finches. This was pointed out to him by the ornithologist entrusted with his collection AFTER he had returned to England. He made many such (false) claims in his "biography" which he wrote late in his life.
I guess the real problem is that science demands theories that can be tested for falsehood..
Consider that I can substitue ANY imagined creature for God and end up in the same place.
Faires created species.. is as valid as God.. or..Zeus.. No I can't show you a fairy.. Nor you show me God.. It's an impasse.
What you end up with is what is sometimes called 'God in the cracks' That is, anything that we can't explain yet, is assumed to be the part that God did.
As soon as we fill in that crack with science.. God must move to the next problem.
Chuck
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
This seems like a good forum to get responses to a theory I've had in my head for about a year now.
Given a mass of matter, floating in space, its atoms interacting with one another making random combinations. Eventually, over billions or even trillions of years, every possible combination of molecular structures will be created from these random interactions.
What if one of these random structures coming out of this process naturally attempts to create copies of itself, using the resources around it? What if this structure doesn't make perfect copies, but creates copies that are the closest it can come to an exact copy with the resources around it? Exactly at what point does this molecular compound become life?
I'm not looking for flames, just good arguments why this can't happen. It's the most reasonable explaination of the source of life that I have come up with.
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!
Let's assume you're right, and all of these societies were corrupt.... (for the sake of argument...) What possible moral code would justify sending in an army, killing everything except the preteen girls, slaughtering the livestock, women and children, INCLUDING INFANTS, and taking said preteen girls back to your camp to be raped? (excuse me... 'married.')
And it's the CAANANITES that were corrupt?
How about Sodom? 'Oops... these people aren't bowing down and grovelling before my all powerfulness... and they're doin icky things with their slippery bits. Guess I'm going to have to drop a mountain on them. (After all... I'm all powerful and I can do that sort of thing.... this God job has some fun perks....) Yes I know it'll kill all of the women and children too... too bad. I guess they should have been born someplace else into different families. (Never mind that as an all powerful God I was the one responsible for having them born there in the first place...) Too bad. Oops. I guess I can't kill EVERYBODY.... this one guy is grovelling enough for my tastes. So I guess I'll send down a flunky or two to get him and his family out of the city before I murder everybody else in it. No problem. It'll make for good press. Of course as an omniscient God I know ahead of time that his wife won't grovel enough... I'll just have to think of some novel way to get rid of her. Hmm... *munches on pretzels* AH HA!!!! SALT!!! Very cool. Sometimes I amaze even myself. And of course I also know that this one righteous man is going to proceed to have a drunken orgy with his own daughters afterward... but hell... he grovels. No problem. I'll overlook it. After all... I'm boss, remember?'
Your precious moral code gives a sociopathic tyrant free reign to do whatever the hell he wants. The sooner we as a society cast off the superstitions of a bunch of illiterate goat herders who respected only power and military strength, the better.
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.