Posted on 01/26/2006 11:47:13 AM PST by PatrickHenry
Jeffrey H. Schwartz's Sudden Origins closed Darwin's gaps; cell biology explains how.
An article by University of Pittsburgh Professor of Anthropology Jeffrey H. Schwartz and University of Salerno Professor of Biochemistry Bruno Maresca, to be published Jan. 30 in the New Anatomist journal, shows that the emerging understanding of cell structure lends strong support to Schwartz's theory of evolution, originally explained in his seminal work, Sudden Origins: Fossils, Genes, and the Emergence of Species (John Wiley & Sons, 2000).
In that book, Schwartz hearkens back to earlier theories that suggest that the Darwinian model of evolution as continual and gradual adaptation to the environment glosses over gaps in the fossil record by assuming the intervening fossils simply have not been found yet. Rather, Schwartz argues, they have not been found because they don't exist, since evolution is not necessarily gradual but often sudden, dramatic expressions of change that began on the cellular level because of radical environmental stressors-like extreme heat, cold, or crowding-years earlier.
Determining the mechanism that causes those delayed expressions of change is Schwartz's major contribution to the evolution of the theory of evolution. The mechanism, the authors explain, is this: Environmental upheaval causes genes to mutate, and those altered genes remain in a recessive state, spreading silently through the population until offspring appear with two copies of the new mutation and change suddenly, seemingly appearing out of thin air. Those changes may be significant and beneficial (like teeth or limbs) or, more likely, kill the organism.
Why does it take an environmental drama to cause mutations? Why don't cells subtly and constantly change in small ways over time, as Darwin suggests?
Cell biologists know the answer: Cells don't like to change and don't do so easily. As Schwartz and Maresca explain: Cells in their ordinary states have suites of molecules- various kinds of proteins-whose jobs are to eliminate error that might get introduced and derail the functioning of their cell. For instance, some proteins work to keep the cell membrane intact. Other proteins act as chaperones, bringing molecules to their proper locations in the cell, and so on. In short, with that kind of protection from change, it is very difficult for mutations, of whatever kind, to gain a foothold. But extreme stress pushes cells beyond their capacity to produce protective proteins, and then mutation can occur.
This revelation has enormous implications for the notion that organisms routinely change to adapt to the environment. Actually, Schwartz argues, it is the environment that knocks them off their equilibrium and as likely ultimately kills them as changes them. And so they are being rocked by the environment, not adapting to it.
The article's conclusions also have important implications for the notion of “fixing” the environment to protect endangered species. While it is indeed the environment causing the mutation, the resulting organism is in an altogether different environment by the time the novelty finally escapes its recessive state and expresses itself.
“You just can't do a quick fix on the environment to prevent extinction because the cause of the mutation occurred some time in the past, and you don't know what the cause of the stress was at that time,” Schwartz said.
“This new understanding of how organisms change provides us with an opportunity to forestall the damage we might cause by unthinking disruption of the environment,” added Schwartz. “The Sudden Origins theory, buttressed by modern cell biology, underscores the need to preserve the environment-not only to enhance life today, but to protect life generations from now.”
Schwartz, with his colleague Ian Tattersall, curator of anthropology at the American Museum of Natural History in New York, also authored the four-volume The Human Fossil Record (Wiley-Liss, 2002-05). Together, the volumes represent the first study of the entire human fossil record. Volume 1 was recognized by the Association of American Publishers with its Professional Scholarly Publishing Award. In 1987, Schwartz's The Red Ape: Orang-utans and Human Origin (Houghton Mifflin Company) was met with critical acclaim.
Schwartz, who also is a Pitt professor of the history and philosophy of science, was named a fellow in Pitt's Center for the Philosophy of Science and a fellow of the prestigious World Academy of Arts and Science.
The journal, The New Anatomist, is an invitation-only supplement to the Anatomical Record.
It's possible to model the changes in allele frequency as a diffusion process. Diffusion processes have things happening at all "distance" scales.
A randomly generated change in allele frequency in conjunction with selection doesn't yield a "random" result as you point out. I was surprised at the speed of "adaptation" though. Originally I expected "drift" to be proportionaly to Sqrt(Time) and selection to be proportional to Time. However, the change in allele frequency (measured from an hypothetical ideal frequency to fit selection function) can be exponentially fast.
No, just a snake that is known for something other than multiplication.
What he describes is regular evolutionary change.
How do you define stress? I ask because I think there's a misunderstanding afloat.
Cool.
Do the models fit real-life data, especialy regarding phenotype?
"Maybe there's more to it than mentioned in the article, but I get the impression that Schwartz has strayed out of his field of expertise, and is making naive mistakes in genetics, population dynamics, and ecology."
I think he should stick with examining bones.
I don't know. I've never done that. There are some studies (which I read, but I don't remember the authors; it was some time ago) that trace gene frequencies using stochastic differential equations. Perhaps a search of GOOGLE SCHOLAR would be useful.
A simple application would be the proof that there is always a "least recent common ancestor" (African Eve). The relation "mother of" (applied to females) is a contraction mapping (there are always fewer mothers than daughters); and thus if iterated, there will be a fixed point; being discrete, the fixed point must consist of a single individual. Similarly for males. Similarly for names.
Not true actually. See "Pressburger Arithmetic." Repeated addition can multiply by any specific number but one cannot then derive all theorems about multiplication. It's amusing.
And Korean stem cell research, and the misinterpretation of the hockey stick phenomenon, and the fact that the whole system is set up to encourage "cutting edge" fraud...
All of what you mention are Nerf sciences. Hard sciences are physics, computer science, etc.
Consider this scenario: the environment has undergone some change (let's say a long-term dry spell). The existing species are under stress. The stress causes mutations
Some breeding pairs are going to find oasis areas where conditions are still viable. The stress they've been under cause mutations which get passed to their offspring. The oasis areas will probably be isolated. So the great-grandchildren of the breeding pair that found the oasis are only going to have each other to breed with. The recessives will get reinforced. Any mutations that allow them to spread out of the oasis are going to be retained, because only individuals who have that gene will be able to survive in the environment outside the oasis, so there won't be anybody else to breed with
Nice try. No cigar.
Thanks for the help. Good information.
It sounds that way to me too.
How do you define stress? I ask because I think there's a misunderstanding afloat.
There *are* differences between environmental change which just causes increased mortality and/or decreased fecundity (reproductive success) in a species, and environmental change which actually "stresses" an organism (i.e. which causes significant enough biochemical changes in its cells to result in a boost in mutation rates). For a trivial example, consider higher background radiation, or mutagenic chemicals in the environment, but higher mutation rates can also be induced by more mundane environmental conditions, like being hotter or colder than the organism can tolerate well, or required nutrients becoming no longer available, etc.
But as previously mentioned, this doesn't cause a different *kind* of evolution to occur, it just generates more mutational grist for the mill of natural selection.
It's interesting that not only do more mutations occur when they might be most "needed" (i.e. when the species has a need to adapt more rapidly), but also some genomes seem to have mechanisms which *actively* turn on a higher rate of mutation when certain environmental conditions are met, and not just as a passive response to a breakdown in normal error-correction mechanisms. Such things would be expected to arise through evolution, whereby an organism "evolves to better evolve".
For example, here's a paper on the topic of what is called "adaptive mutation": Stress responses and genetic variation in bacteria. Also: Adaptive amplification and point mutation are independent mechanisms: evidence for various stress-inducible mutation mechanisms
Otherwise, of course, the recessive gene disappears after just a few generations.
All of what you mention are Nerf sciences. Hard sciences are physics, computer science, etc.
What's so hard about those? Lifting those heavy pencils?
Now digging square holes in the hot sun, that's hard science!
I wasn't claiming an original thesis.....
By Robert N. Bostrom
This summer marks the 20th anniversary of the Flat Earth Society's founding, and I'm sorry to say that the media have largely ignored our organization and its contribution to contemporary thinking and the quality of life.
The society was founded to defend the right of Americans to insist on equal treatment by the school systems and a balanced approach to the teaching of science. It has been well established that the beliefs of individuals must be considered when schools design curricula.
Imagine the feelings of a child whose family believes in a flat Earth and has to hear that some of their most precious beliefs are ignored, or worse, derided. Oppressive government and lock-step educational institutions insist that they know everything, in spite of the massive evidence to the contrary.
If you've ever been to Kansas, you know the Earth is flat. If you've been up in a lighthouse and looked out at the ocean, you can see that this planet is as flat as can be. In spite of the evidence of our senses, schools everywhere in America are continuing to teach about the round Earth as if it were an established fact and not just a theory, which it is.
We of the Flat Earth Society want equal time in the schools to see that our point of view is presented as an alternative to the established view that the Earth is round. We want to start out by having the globes in schools and publicly funded institutions carry a warning sign that they represent only one view of the shape of the Earth and that other theories are worth our attention.
All of the so-called evidence for a round Earth theory is indirect and can be interpreted in many ways. We know that Magellan actually sailed in a great circle and not around the world as he claimed.
And recently, we have seen pictures taken by so-called astronauts that purport to show a round Earth. If you really believe the astronauts went to the moon and not to Arizona, you are dumber than we think.
Nonetheless, Flat Earth members have not had nearly as much media attention as we would like. Our friends who espouse scientific creationism have done much better, and we believe that their success has been due to the support of churches and religious organizations.
At first it may seem odd that a church would have a point of view about scientific questions, but you can't argue with success. The creationists have browbeaten school boards and departments of education into allowing mention of their theories in school science classes, and we want the same respect.
From most science teachers' point of view, a flat Earth is no more ridiculous than a magical account of creation with floods and miraculous creation from ribs and stuff. So it is obvious that we need to enlist churches in our cause, and we are negotiating with some of the more enlightened groups to support us.
We were horribly disappointed when the Catholic Church announced that Galileo was right after all, and so we have given up on it. But if anyone out there is interested in forming an alliance, we would like to talk to you. Look in your Bible; you won't find anything about a round Earth in it.
In spite of hardship, the Flat Earth Society continues its efforts, and we think the next 20 years will be better. We know that liberal newspapers will pay us little attention, so we are going to rely on word of mouth. Our word to you is to trust your senses and don't let scientists pull the wool over your eyes.
If nothing else, we want views about a round Earth treated as the theories that they really are and not established fact. Equal time is the American way.
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