Posted on 01/20/2003 7:01:47 AM PST by forsnax5
That enduring metaphor for the randomness of evolution, a blind watchmaker that works to no pattern or design, is being challenged by two European chemists. They say that the watchmaker may have been blind, but was guided and constrained by the changing chemistry of the environment, with many inevitable results.
The metaphor of the blind watchmaker has been famously championed by Richard Dawkins of the University of Oxford. But Robert Williams, also at Oxford, and Joäo José R. Fraústo da Silva of the Technical University of Lisbon in Portugal say that evolution is not strictly random. They claim Earth's chemistry has forced life to evolve along a predictable progression from single-celled organisms to plants and animals.
Williams and da Silva take as their starting point the earliest life forms that consisted of a single compartment, or vesicle, enclosing the cytoplasm that produced polymers such as RNA, DNA and proteins. That cytoplasm was partly dominated by the reducing chemistry of the primitive oceans and atmosphere from which it formed, and has changed little since, says Williams.
As these primitive cells, or prokaryotes, extracted hydrogen from water they released oxygen, making the environment more oxidising. Ammonia became nitrogen gas, metals were released from their sulphides, and non-metal sulphides became sulphates.
These changes forced the prokaryotes to adapt to use the oxidised elements, and they evolved to harness energy by fixing nitrogen, using oxygen, and developing photosynthesis. But these oxidising elements could also damage the reducing chemistry in the cytoplasm.
For protection, there was just one option: isolate the elements within internal compartments, says Williams. And that gave rise to eukaryotes - single-celled organisms with a nucleus and other organelles.
Harold Morowitz, an expert on the thermodynamics of living systems at George Mason University in Fairfax, Virginia, says these ideas are very exciting. "It's part of a quiet paradigm revolution going on in biology, in which the radical randomness of Darwinism is being replaced by a much more scientific law-regulated emergence of life."
According to Williams and da Silva, eukaryotes also had to evolve a way to communicate between their various organelles. The surrounding raw materials dictated how this could be done. Calcium ions would have routinely leaked into cells, precipitating DNA by binding to it. So cells responded by pumping the ions out again.
Eukaryotes evolved to use this calcium flow to send messages across internal and external membranes. Similarly, sodium ions formerly expelled as poisonous became the basis of communication in nerve cells.
Life continued to react to Earth's oxidised environment. Hydrogen peroxide gave rise to lignin - an oxygen-rich polymer that is the chief constituent of wood. And eukaryotes used copper oxidised from copper sulphides to cross-link proteins such as collagen and chitin, which help hold nerve and muscle cells in place. Such evolution of materials suitable for multicellular structures paved the way for plants and animals.
Not everyone is convinced. Evolutionary biologist David Deamer of the University of California, Santa Cruz, says the claim that evolution followed an inevitable progression should be qualified: "The inevitability depends on the origin of life and oxygenic photosynthesis."
He agrees that life arose in vesicles, but says that oxidative chemistry cannot explain everything from prokaryotes to humans.
Williams admits their theory has limitations. For instance, he agrees that Dawkins's argument is correct in that chance events drive the development of species. But he does not believe random events drive evolution overall. "Whatever life throws away will become the thing that forces the next step in its development."
However, David Krakauer, an evolutionary theorist at the Santa Fe Institute in New Mexico, says Williams and da Silva have simply listed the chemical processes that coincided with each evolutionary transition, which does not prove that the chemistry caused the transitions. But Williams says that the environmental changes had to come first, because they occur faster than changes in biological systems.
I'm not fully versed in the literature of evolution, but I think it's well-accepted that the primeval atmosphere was anoxic and that free oxygen developed via photosynthesis. CO2 has likewise varied by at least an order of magnitude and is controlled in the long run by tectonism, volcanism and rock weathering rates.
As for extinctions, atmospheric chemistry changes fairly significantly between glacial and interglacial periods without extinguishing life or anything of the sort. This is known from direct measurement of air bubbles trapped in polar ice. Furthermore life has survived numerous cataclysmic impacts and disruptions.
"To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree.
Yet reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if any variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real. How a nerve comes to be sensitive to light, hardly concerns us more than how life itself first originated; but I may remark that several facts make me suspect that any sensitive nerve may be rendered sensitive to light, and likewise to those coarser vibrations of the air which produce sound."
The impossibility of the evolution of the eye (according to Michael Behe):
What is needed to make a light sensitive spot? What happens when a photon of light impinges on the retina?
When a photon first hits the retina, it interacts with a small organic molecule called II-cis-retinal. The shape of retinal is rather bent, but when retinal interacts with the photon, it straightens out, isomerizing into trans-retinal. This is the signal that sets in motion a whole cascade of events resulting in vision. When retinal changes shape, it forces a change in the shape of the protein rhodopsin, which is bound to it. Now part of the transducin complex dissociates and interacts with a protein called phosphodiesterase, When that happens, the phosphodiesterase acquires the ability chemically to cut a small organic molecule called cyclic-GMP, turning it into 5'-GMP. There is a lot of cyclic-GMP in the cell, and some of it sticks to another protein called an ion channel. Normally the ion channel allows sodium ions into the cell. When the concentration of cyclic-GMP decreases because of the action of the phosphodiesterase, however, the cyclic-GMP bound to the ion channel eventually falls off, causing a change in shape that shuts the channel. As a result, sodium ions can no longer enter the cell, the concentration of sodium in the cell decreases, and the voltage accross the cell membrane changes. That in turn causes a wave of electrical polarization to be sent down the optic nerve to the brain. And when interpreted by the brain, that is vision. So this is what modern science has discovered about how Darwin's 'simple' light sensitive spot functions.
From: Michael Behe, 'Design at the Foundation of Life".
Now which one of the two is science and which one is not?????
Obviously Ahban does not understand evolution. Evolution is rapid only when evolutionists say so. At other times it can be slow, slower, slowest and virtually non-existent. Only an evolutionist is qualified to determine what the proper speed is under the given circumstances (and what is needed as proof of evolution).
Great point! Interestingly, while evolutionists claim that environment causes genetic changes, they completely reject Lamarckism (that the environment is the cause of the changes in species).
Plants cannot live without oxygen.
Shhh - don't tell these guys....
Ie this is the theory the evolutionists like today.
As for extinctions, atmospheric chemistry changes fairly significantly between glacial and interglacial periods without extinguishing life or anything of the sort. This is known from direct measurement of air bubbles trapped in polar ice. Furthermore life has survived numerous cataclysmic impacts and disruptions.
Air bubles in ice prove there are air bubbles in ice. What they prove beyond that is subjective. And life has survived some pretty terrible things. There's just no evidence that life has been through noxious chemical changes in the atmosphere, witnessed GEEs or evolved as result of such change rather than perishing. Moreover, Science can only guess if the planet was ever without an atmosphere or that it was ever other than what it is today with variations on c14. In short, what you are stating as fact is merely theory.
I would throw in a good question about how wooley mammoths could be flash frozen in mid stride such that even the contents of freshly chewed food in the stomache and mouth are undigested and intact. Might also ask how a "polar" climate animal (as evolutionists define them) can eat buttercups, green grass and the like in far northern Siberia. Really puts a nasty wrinkle in things. Buttercups don't grow on frozen tundra. Nor evidently do Mammoths. And if there are tropical forests a mile under ice, where'd all the water come from necessary to bury a land mass that large under a mile of ice. Hmmm. Good questions all; but, evolution can't explain them as a whole. Oh well. looking forward to the entertainment to come.
You were counting the asteroid belt. Yeah, that's the ticket...
Right! Used to be the 8th planet. Of course. I must have been reading from a very old tour guide. Gotta clean out my office one of these days.
They can live longer without oxygen than insects so one can kill the insects by depriving them of oxygen without killing the plants in a greenhouse. Not what we are talking about at all is it?
Now which one of the two is science and which one is not?????
Darwin's is, since he lays out a specific hypothesis which can be examined and tested (and if found wanting, falsified).
Behe, on the other hand, describes the activity of a *modern* eye (note he starts out talking about a "retina"), then at the end pulls a bait-and-switch and implies that such things are necessary for a primitive "light sensitive spot".
Just like your dishonesty on another thread, that's like trying to "prove" the impossibility of the Wright Brothers making a working airplane in their garage by waving the high-tech plans for a Stealth Bomber -- and thus pretending to have proven that the entire aviation industry was too improbable to believe.
That's not science, that's dishonest lawyering.
Nice try.
The stories of the flash frozen mammoths get more detailed and more dramatic with every retelling. The most famous find (until the very recent one) was the "Beresovka Mammoth," found largely intact in Russia in 1901. There wasn't a lot of excitement about it until the mid-50's, when Immanuel Velikovsky picked up on it.
Immanuel Velikovsky became notorious in 1950 when he published Worlds In Collision. Velikovsky believed in literal interpretations of ancient texts that described bizarre occurrences, and he devised theories of catastrophic events to explain them.
He followed with another, lesser known book in 1955 called Earth In Upheaval. In this book, he explained the demise of the mammoths, and it's recounted here.
From the link:
The evidence for these catastrophes had to be largely geological. Velikovsky was fascinated by the profusion of mammoth bones and tusks and even frozen bodies that had been found in Siberia and Alaska. There were three key points as far as he was concerned: one, that the existing tundra seemed totally inadequate to provide enough plant material for huge animals like mammoths to subsist on. The second point, related to the first, was that their stomachs contained the remains of plants that couldn't have grown so far north. And three, the frozen mammoths seemed to have been flash frozen. To Velikovsky, the only possible explanation was that these animals had been living in a much more temperate clime, which had suddenly - and I mean suddenly - turned ice-cold.
And here's how he explained this strange turn of events:
"Let us assume, as a working hypothesis, that under the impact of a force or the influence of an agent - and the earth does not travel in an empty universe - the axis of the earth shifted or tilted. At that moment an earthquake would make the globe shudder... The shifting of the axis would also change the climate of every place, leaving corals in Newfoundland and elephants in Alaska..." So some unidentified cosmic object disturbed the Earth and one of the myriad effects was the death and preservation of mammoths in ice. Later he argues that the famous Beresovka mammoth, found with clots of blood in its chest and unswallowed grass clenched between its teeth, is a testimony to the violence and suddenness of whatever cataclysmic event caused the extinction of its species.
So how well do the arguments stand up under scrutiny? Not very well. First, were the mammoths quick-frozen? No. Almost all of the frozen specimens found so far have been rotten, and in some cases, mutilated by scavengers before freezing. Even the ground around the aforementioned Beresovka mammoth, as well as the mammoth's flesh, stunk of decay. Had freezing been instantaneous, no decay would have occurred. That is why we have fridges, isn't it?
They died, not by freezing, but by asphyxiation. Evidence for that is the discovery of vessels still filled with coagulated blood and the little-known fact that the Beresovka mammoth died with an erection.
Second, the stomach contents. Turns out both the Mamontova and Beresovka mammoths had eaten a variety of plants, including grasses, sedges and other tundra plants, as well as the cones and twigs of northern trees. Overall these plants represent a flora that would exist in slightly warmer and wetter conditions than exist in Siberia today, but such conditions are well within the climatic variability of the past.
There are some other points that Velikovsky seems to have overlooked, one of which is that the mammoths were obviously adapted to Siberian cold. They had long hair, a woolly undercoat and a thick layer of subcutaneous fat.
Finally the numbers of frozen mammoths don't support the idea of a catastrophe. It's been estimated that there might have been about 50,000 mammoths living in the Arctic, while something like forty have been found frozen. Hardly the signs of a cataclysmic event.
As well, only mammoths and woolly rhinoceroses have been found frozen. Why only them and no other animals? Presumably because they were heavy and unable, if they fell, to extricate themselves from either marshy ground or snow-filled gullies. Elephants, and presumably mammoths before them, need to be balanced so precisely on their pillar-like legs that they can't cross a ditch any wider than their stride length.
Most of the evidence on both sides of this argument comes from the 1950s and earlier, but you shouldn't take that as evidence that this controversy is dead. In fact there is a 303 page book published in 1997 called The Extinction of the Mammoth, by Charles Ginenthal that revisits the controversy. Mr. Ginenthal appears to be Velikovsky supporter, and the publication of this book shows that Velikovsky's influence on scientific discourse has not waned.
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