Skip to comments.Scientists find evolution of life
Posted on 10/30/2003 5:04:39 PM PST by Dales
LIVERMORE, Calif. -- A trio of scientists including a researcher from the Lawrence Livermore National Laboratory has found that humans may owe the relatively mild climate in which their ancestors evolved to tiny marine organisms with shells and skeletons made out of calcium carbonate.
In a paper titled "Carbonate Deposition, Climate Stability and Neoproterozoic Ice Ages" in the Oct. 31 edition of Science, UC Riverside researchers Andy Ridgwell and Martin Kennedy along with LLNL climate scientist Ken Caldeira, discovered that the increased stability in modern climate may be due in part to the evolution of marine plankton living in the open ocean with shells and skeletal material made out of calcium carbonate. They conclude that these marine organisms helped prevent the ice ages of the past few hundred thousand years from turning into a severe global deep freeze.
"The most recent ice ages were mild enough to allow and possibly even promote the evolution of modern humans," Caldeira said. "Without these tiny marine organisms, the ice sheets may have grown to cover the earth, like in the snowball glaciations of the ancient past, and our ancestors might not have survived."
The researchers used a computer model describing the ocean, atmosphere and land surface to look at how atmospheric carbon dioxide would change as a result of glacier growth. They found that, in the distant past, as glaciers started to grow, the oceans would suck the greenhouse gas -- carbon dioxide out of the atmosphere -- making the Earth colder, promoting an even deeper ice age. When marine plankton with carbonate shells and skeletons are added to the model, ocean chemistry is buffered and glacial growth does not cause the ocean to absorb large amounts of carbon dioxide from the atmosphere.
But in Precambrian times (which lasted up until 544 million years ago), marine organisms in the open ocean did not produce carbonate skeletons -- and ancient rocks from the end of the Precambrian geological age indicate that huge glaciers deposited layers of crushed rock debris thousands of meters thick near the equator. If the land was frozen near the equator, then most of the surface of the planet was likely covered in ice, making Earth look like a giant snowball, the researchers said.
Around 200 million years ago, calcium carbonate organisms became critical to helping prevent the earth from freezing over. When the organisms die, their carbonate shells and skeletons settle to the ocean floor, where some dissolve and some are buried in sediments. These deposits help regulate the chemistry of the ocean and the amount of carbon dioxide in the atmosphere. However, in a related study published in Nature on Sept. 25, 2003, Caldeira and LLNL physicist Michael Wickett found that unrestrained release of fossil-fuel carbon dioxide to the atmosphere could threaten extinction for these climate-stabilizing marine organisms.
From the links general_re has provided, it appears the Schopf group is meeting November 4th. They've scheduled presentations to noon and then have blocked the rest of the day off with just presenters noted.
I will be very disappointed if this is just drop-a-paper-and-run. Representatives from most disciplines would be there to hammer out some integrated approach - and the title of the session is "The Hunt for Precambrian Life: An Integrated Approach" Sigh...
Was that lake covered by ice for one season of for hundreds of millions of years. Life can survive for one season under ice. It cannot survive for hundreds of millions of years under ice. The SciAm article is bunk.
Nonsense. Science requires observation, and not one single species has ever been observed transforming itself into a more complex species. However, we see uncountable times a day that the progeny are like the parents.
From the Scientific American article you dismissed out of hand apparently without reading:
"Hints of a harsh past on the earth began cropping up in the early 1960s, but we and our colleagues have found new evidence in the past eight years that has helped us weave a more explicit tale..."So... When you say, "If it was correct there would be tremendous amounts of evidence for it and such a claim would have been made decades ago", what can we deduce from the fact that such a claim *was* indeed made "decades ago"?
[...] "The search for the surprisingly strong evidence for these climatic events has taken us around the world."
[...] After hundreds of millions of years of burial, these now exposed rocks tell the story that scientists first began to piece together 35 years ago.
[...] "In 1964 W. Brian Harland of the University of Cambridge pointed out that glacial deposits dot Neoproterozoic rock outcrops across virtually every continent."
[...] "Realizing that the glaciers must have covered the tropics, Harland became the first geologist to suggest that the earth had experienced a great Neoproterozoic ice age [see 'The Great Infra-Cambrian Glaciation,' by W. B. Harland and M.J.S. Rudwick; Scientific American, August 1964]."
[...] "The first of these objections began to fade in the late 1970s with the discovery of remarkable communities of organisms living in places once thought too harsh to harbor life."
[...] "In the 1960s Martin J. S. Rudwick, working with Brian Harland, proposed that the climate recovery following a huge Neoproterozoic glaciation paved the way for the explosive radiation of multicellular animal life soon thereafter."
The fact that you haven't heard of something is not sufficient grounds for you to declare that it didn't happen. You would benefit from researching things instead of posting your assumptions as fact. In this case, you needn't have gone any farther than material that was already provided on this very thread. Reading it instead of dismissing it unread would have been useful and educational.
Science is much more than just a process. It is the vast amount of accumulated evidence and discoveries and verified theories which have been gathered for hundreds of years. Attempting to discuss science -- or worse, attempting to refute it -- without being familiar with at least a substantial grasp of that body of knowledge is a recipe for failure.
There is no evidence for these claims that is why they use 'computer models'.
They have massive evidence for those claims, which is *why* they use computer models to handle the amount of information.
You can model whatever you like on a computer and make it come out any way you wish.
Not if you do it honestly and carefully, you can't. Are you accusing them of being dishonest?
Sometimes I think that more lies are told with spreadsheets than with tongues.
Hmm, I guess you are.
If you distrust computer models so much, what alternative method would you propose for determining the results of the complex interactions-over-time of large systems?
And then publish the cook book? Demand the whole field use it?
And that dispute will be a subject of a seminar scheduled for November:Hey, that's next week! And in my hometown too. Cool!
First Announcement: The Hunt for Precambrian Life: An Integrated Approach
There will be debate. Often these sessions are recorded by individuals, although, I don't think there will be published minutes.
Whaddya, movin' in on my territory? *I'm* the funny one. *You're* the stern one.
Now, knock it off!
Alas, I don't have $40 to spare to get to the (one) presentation. Plus I have to work.
Maybe I could flash my credentials as webmistress of Creation/Evolution: The Eternal Debate & get in for free. That'll impress 'em! :-)
No, they did not, as any reading of their works would make entirely clear.
For a succinct example:
"We believe that Huxley was right in his warning. The modern theory of evolution does not require gradual change. In fact, the operation of Darwinian processes should yield exactly what we see in the fossil record. It is gradualism we should reject, not Darwinism."Furthermore, even many people who should know better *incorrectly* claim that Darwin propounded a theory of strict steady gradualism, and that Gould and Eldredge were proposing a departure from Darwin when they championed Punctuated Equilibrium (i.e. the notion that speciation often proceeds by relatively short bursts of change followed by longer periods of stasis).
- Gould, Stephen J. The Panda's Thumb, 1980, p. 181-182
Instead, it's the *gradualist* school of evolution which had drifted away from Darwin, and Gould and Eldredge were *returning* to Darwin's original insights. See for yourself:
I further believe that these slow, intermittent results accord well with what geology tells us of the rate and manner at which the inhabitants of the world have changed." (Darwin, Ch. 4, "Natural Selection," pp. 140-141)This is classic Punctuated Equilibrium -- from Charles Darwin in 1859.
But I must here remark that I do not suppose that the process ever goes on so regularly as is represented in the diagram, though in itself made somewhat irregular, nor that it goes on continuously; it is far more probable that each form remains for long periods unaltered, and then again undergoes modification. (Darwin, Ch. 4, "Natural Selection," pp. 152)
"It is a more important consideration ... that the period during which each species underwent modification, though long as measured by years, was probably short in comparison with that during which it remained without undergoing any change." (Darwin, Ch. 10, "On the imperfection of the geological record," p. 428)
"Widely ranging species vary most, and varieties are often at first local, -- both causes rendering the discovery of intermediate links less likely. Local varieties will not spread into other and distant regions until they are considerably modified and improved; and when they do spread, if discovered in a geological formation, they will appear as if suddenly created there, and will be simply classed as new species. [Charles Darwin, Origin of Species 1st Edition 1859, p.439]
[All quotes from Darwin's 1859 "On the Origin of Species"]
So where, exactly, do you think that Gould and Eldredge "completely rejected" Darwin?
because the Cambrian showed that organisms appeared suddenly and could not have evolved over time.
Really? Cite, please?
For this reason they took up and formulated what they themselves called punk-eek,
...returning closer to Darwin by doing so...
a totally silly theory similar to claiming that ghosts exist but have never been photographed because they are too shy to have their picture taken.
Fascinating. Please outline the manner in which you think this actually parallels Punctuated Equilibrium. It bears no resemblance to *my* knowledge of PE.
They said that new species arise suddenly and leave no trace of what happened.
No, they say that as a direct consequence of the manner in which evolution works, species-to-species transitions would be quite difficult to find, because they occur relatively quickly in geological terms, and most often locally rather than over a broad geographical area. Thus tripping over fossils of such transitions is rather like trying to find needles in a very, very large haystack.
Nonetheless, contrary to your implication that such finds are non-existent, due to the large numbers of speciation events in Earth's history, we *are* lucky enough to find some. For details, check out for example the 139 examples presented in Cuffey, RJ, 1984, Paleontologic Evidence and Organic Evolution, in Montagu, A., ed., Science and Creationism: New York, Oxford University Press.
For a quick overview:
Examination and collection of the rock and fossil record (either outcrops or subsurface cores) naturally produces many such stratigraphically, superpositionally, and hence geochronologically successive samples that show gradual and continuous morphologic change from older species into younger species (Cuffey, 1984). Numerous examples of such transitional individuals, consisting of sample by sample intermediate forms, completely documenting morphologic change between species (in some cases connecting more than one higher taxon) exist among protists, several invertebrate phyla, and vertebrates, especially mammals including hominids (Cuffey, 1984, p. 258, 259). Additional research has provided many other examples of transitional individuals in protists (Lazarus, 1983, 1986; Malmgren, Berggren, & Lohmann, 1983, 1984; Arnold, 1983), bryozoans (Cuffey, 1999), brachiopods (Hurst, 1975), conodonts (Barnett, 1972), mammals (Rose & Bown, 1984; Bookstein, Gingerich, & Kluge, 1978; Gingerich & Simons, 1977; Gingerich & Gunnell, 1979; Chaline & Laurin, 1986; Clyde & Gingerich, 1994; Gingerich, 1974, 1976a, 1980, 1985), and hominids (Cronin, et al., 1981; Wolpoff, 1984).I'm sorry, what's that you've been saying about no transitional fossils, and no evidence for evolution?
Based upon these data, we can conclude that new species arise by descent with modification that occurs through successive generations, each produced by normal reproductive processes. Furthermore, the rates of morphologic change are highly variable. Some change is essentially constant and unidirectional, slow or fast; this is classic phyletic gradualism (Gingerich, 1974, 1976a). Other change is irregular consisting of intervals of slow change or stasis interrupted by intervals of very rapid change. This rapid change may be clearly resolvable but compressed into a narrow interval (termed punctuated gradualism; Malmgren, Berggren, & Lohmann, 1983) or so rapid that, on a geologic time frame, the transitional samples are not resolvable (termed punctuated equilibrium; Cheetham, 1986). Moreover, such change can proceed in a straight line linking a succession of several species (termed anagenesis or phyletic transformation; Ziegler, 1966; Gingerich, 1974, 1976a, 1985; Sheldon, 1990) or one species can produce two or more species in a branching pattern (termed speciation or cladogenesis; Gingerich, 1974, 1976a, 1985; Lazarus, 1986; Sheldon, 1990). These empirical observations are direct evidence of descent with modification, and lead to the inescapable conclusion that evolution has occurred.
- (excerpt from THE FOSSIL RECORD: EVOLUTION OR "SCIENTIFIC CREATION". The entire paper is excellent and worth a read.)
But then you knew that already did you not?
I'm pretty sure that she was not previously aware of your erroneous statements.
That's going to come as a big surprise to these folks:
"Creation Education: Is Creationism Important in Education?" by Henry M. Morris, Ph.D. [...] " In the case of the American nation, its educational and political institutions were in fact originally established on creationist principles." [from http://www.answersingenesis.org/home/area/magazines/docs/v10n3_educate.asp]And so on.
"Reproduced below are the ICR Educational Philosophy and its Tenets of Scientific Creationism and Biblical Creationism. [...] ...providing the most satisfying and meaningful structure of a consistently creationist and Biblical framework..." [from http://www.icr.org/abouticr/tenets.htm]
"Scientific Creationism is a web site dedicated to refuting evolution and promoting creationism, but in particular promoting the Bible as true in all it says and claims. [...] The views of creationists [...] Common misconceptions about the beliefs of Creationists" [from http://www.scientificcreationism.org/]
"Creationism Connection [...] The purpose of this page is to provide information resources for Biblical Creationists or anyone interested in creationism (go to Directory ). [from http://members.aol.com/dwr51055/Creation.html
Those opponents most often call themselves Christians or ID'ers or just non-believers in evolution than creationists.
If you think that using the words "creationism" or "creationist" is a sign that "gives someone away" as not being a real Christians/ID'ers, then I guess the Institute for Creation Research, Answers in Genesis, Henry Morris, and so on are all now exposed, eh?
If the authors made this claim in their paper, they are mistaken. CaCO3 will dissolve below the CCD (carbonate compensation depth), thus in all but shallow regimes, calcareous remains are absent.
That's it...we're confiscating your modem.
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