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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.
I bet it's easy to go through life thinking you're a biological mistake. No morals, no absolute truth; no right or wrong. It's all random chemical interactions in your brain. Rape, steal, kill. No reason not to if this is all there is.
Ignorance is bliss.
You won't "win" the argument. Faith is the 800 pound gorilla, the bull in the china shop, the nuclear bomb of arguments. You don't have to think or justify yourself, bam, that's all!
Dare I say it... :-P
"AMEN!"
Creationism, Evolution... They're both theories.
Any scientist who says one "did" absolutely positively happen is practicing a faith, not science. In essence, they're both religions, with whacko irrational devotees on both sides.
Hey, dude, if you honestly need to believe in a God that will sentence you to eternal torture in order to keep yourself from raping, stealing, and killing, then .. wow. Please, by all means, continue to believe. My personal concern is for the safety of my family, and if your beliefs will prevent you from harming them, then please hold on to them.
Some of us have gotten past all of that and have realized that you don't need a vengeful deity holding a metaphorical shotgun to your head in order to behave in a moral and ethical matter. But if you're not there yet, then please do whatever it takes, dude.
Creationism, Evolution... They're both theories.
Any scientist who says one "did" absolutely positively happen is practicing a faith, not science. In essence, they're both religions, with whacko irrational devotees on both sides.
Evolution is like gravity, both fact and theory. The fact is that it does, has, and will continue to happen. The theory is how it happens. Darwin's contribution was not evolution's existence; this much was already known. His contribution was a mechanism for evolution to happen--descent with modification due to natural selection.
Claiming that evolution and creation are both "just theories" shows an astounding ignorance of science. "Theories" are models used that best fit the available evidence. Putting both creation and evolution in this category would need several steps up just to get to "wrong." Where evolution is concerned, we have physical evidence, genetic evidence, laboratory evidence, and observation. Where creation is concerned, we have....A book that says it happened.
Gifts for Geeks - Stuff that really matters!
Time to burn some karma. I've heard this so many times, and it always frustrates me greatly!
Creationism, Evolution... They're both theories.
Um... The first is based on faith, the second on careful observation of the natural world. Hardly equal terms, I'd say.
Alternatively, taking your argument further:
You may have a theory that the earth will continue to rotate for another 24 hours. Of course, it's just a theory, and all theories are equivalent. So I should not feel obligated to come up with ones that match reality. I have a new theory, that the earth will stop rotating in eight hours. Just try and prove me wrong *right* *now*!
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.
No morals, no absolute truth; no right or wrong.
Wrong. Morals are created by human beings.
The moral code YOU apparently believe in was created by a band of savage goat herders in the Middle East thousands of years ago, not by some spook. The spook part is just to delude the ignorant.
If you want to see the consequence of applying the moral code of savage Middle Eastern goat herders to the modern world, I direct you to Ground Zero, New York, New York.
You think Christanity or Judaism are any better? Try actually READING your Bible, rather than thumping it. Start with Numbers Chapter 31.
It may give you a whole different perspective on the presumed raping, killing, and murdering that you allege will be committed by nonbelievers.
Your moral code sucks. It was designed for ignorant savages. If you adhere to it, that makes YOU an ignorant savage.
The entire concept of a "species" is the problem; the "loose grey zone" is the reality.
We classify organisms into species in order to make some sense of what we observe, but we should always keep in mind that the classification is artificially imposed, and somewhat arbitrary. The fossil record of any group of related organisms shows discrete snapshots of a continuous variation through time and geography (punctuated equilibrium does not refute this, it just says that the rate of evolution is not constant).
The species model describes evolutionary change as "creatures evolving from species A to species B to species C", with the implicit understanding that these are just arbitrary markers along the continuous evolutionary path, not coincidentally placed where there are well-preserved examples in the (incomplete) fossil record.
Unfortunately, this implicit understanding doesn't really get through to popular understanding of evolution; hence the many heated debates about speciation and how to tell when it occurs, when in fact speciation is not a real phenomenon at all, but a classification tool.
Liberal (adj.): Free from bigotry; open to progress; tolerant of others.
Ur,how does this have any relevance to the validity of the theory of evolution?
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
Creationists seem to think that evolutionists in some way hold to Darwin. They do not. They care about the theory itself, not about the bearded fellow who came up with it. Don't think of Darwin as our Jebus.
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.
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.
Yes, of course it happened. The question is not whether it happened or not, but how it happened. You seem to be assuming that the mere fact that it happened proves that it happened without any intelligent design. In other words, you are confusing your premise with your conclusion. That's alright, evolutionists do it all the time.
I watch Brit Hume on Fox News
Excellent post. Would mod up if I had any points right now!
This fundamental misunderstanding of the word "theory" in a scientific context, and really science in general, is what annoys me most about those who call evolution "just a theory."
After all, Newton's "laws" of physics were later disproven. They were pretty good estimates but not actually correct. Every scientific explanation is "just a theory" until some better explanation comes along.
Heck, creationism was the best "theory" until Darwin came up with a better one.
Science is basically impossible without the realization that every explanation is incomplete. A committment to any idea is irrational, because a better idea is just around the corner.
Most creationists seem to think that "science" views the world in the same blind faith way that they they do, either accepting or discarding ideas wholesale. In fact those who accept "science" would be ready to drop evolution, relativity, quantum theory etc. should better explanations come along.
At present, I do not put much stock in the theory of evolution. Specifically, I see two holes in the theory.
The first problem I have is the small number of species in the fossil record. Evolution predicts the past existence of millions of species and we've only got thousands of different fossils. Basically, our copy of the record seems to be missing millions of species. It's so lacking that, of all the fossils we have, none of them are direct ancestors or descendants of any other fossil. We are missing links between every known point in the fossil chain which, of course, could imply that there is no chain. This lack of fossils is something Darwin mentioned as a problem in the "Origin of Species" (I don't remember exactly where) and, 130+ years later, this exact same problem still remains. In my opinion, our incomplete fossil record is, at best, inconclusive as supporting evidence and, at worst, damning as counter evidence.
The second problem I have with the theory is the lack of evidence for mutations increasing the amount of information in a gene pool. As I see it, there are two halves for the working theory of evolution: natural selection (reducing information) and mutation (increasing information). Natural selection has a lot of evidence and examples are seen all the time in the world. In contrast, mutation doesn't have any real world examples (again, that I know) of increasing the information of a gene pool over time. Basically, I'm saying that it is not sufficient to say that randomness 'just works'. At least show me how it works or, failing that, at least provide an actual working experiment showing randomness adding information to a system. I'd personally love to see a computer simulation demonstrating a gene sequence containing more information in it and arrived at only through random twiddling of the gene sequence.
Sorry for the long winded response but I really think there are some fatal flaws in the present theory. Anyone who knows better, please feel free correct this post.
Thanks,
AC
Quote: Don't confuse "theory" with "unproven idea".
I think they are the same thing. Gravity is the description of an observed phenomenon. You can't prove gravity exists. It is "unproven". You can prove that two objects are attracted to each other, but you can't explain why. You also can't very well have a control and a test group.
Evolutionism vs Creationism is facinating to me. Both are hampered by the fact that neither has been proven. Evolutionists have demonstrated that there seems to be a correlation in physiological features of organisms over time, but they can't prove the cause-effect relationship (where's the control and test groups?). Correlation does not prove causation. The entropy argument I think is valid. Why would order increase in organisms? If evolution is real, then every single attribute about every single origanism is the result of an increase in order (for one reason or another) over time, and multiple times. If any one attribute could be proven to not be the result of evolution over time, then there would be a problem.
The creationists can only go on faith. They acknowledge the mountain of evidence for evolution but cannot accept the proposed explanation to be valid. This is not unusual. Do we only accept facts because we observe them? Do we accept all facts even if our direct observations show otherwise? Some creationists try to find some middle ground by trying to accept evolution but not deny the hand of God, which can result in either redefining creation, or redefining evolution. Creationists will never be able to prove creationism (well, unless...), so they are always on the definsive in the scientific community.
I'd like to see some tests. Can we create a digital world and see what happens over time?
I think the best logical argument against evolution is Microsoft (no, really!). I mean, given all the copies of Windows running around the world, how many of them have improved themselves or had their entropy decreased, excluding direct human input? Would there need to a minimum level of intelligence for the computers to start improving themselves? What is the reason for evolution?
What's happening today is that roles of science and the church have essentially reversed. Now it is science that wields the authority, not the church. And with regard to evolution, science is doing exactly what the church once did: repressing and ridiculing dissenters. Ever noticed that most of the scholarly oppositioin to evolution comes from retired biologists or scientists in other fields. That's because a biologist seriously jeopardizes his or her career by coming out prominently against (Neo-Darwinian) evolution. Yet many of those same biologists attend church regularly. They obviously don't subscribe to Dawkins hard-core atheistic position.
I watch Brit Hume on Fox News
The Neo-Darwinian theory of evolution says that all life evolved as the result of random mutations combined with natural selection. The driving force is therefore random mutation. Natural selection can do nothing except select the random mutations that happen to occur. The point is that no intelligent design is necessary, according to the theory. Spetner argues conclusively that this model does not cut it. RTFB.
Oh, I know. It's an unfair debating tactic to simply refer you to the book. OK, fine. RTFB.
I watch Brit Hume on Fox News