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.
Those are some of the worst kind.
Actually it is quite easy to tell you are an evolutionist from the posting of this thread.Very poor assumption, which is staggering to see you make after I pretty much told you it would be a mistake to do.
I went to google news. I typed in evolution. Got one. Posted it. I went back to google. I typed in creationism. Got one. Posted it. So unless google works like my Magic 8 Ball on my desk, and could sense what my views are when it returned those two stories, there was nothing to tell from the choice of stories.
(I left out a step. I checked for duplicates before posting).
On both, I gave the same warnings. No flame wars, no baiting. And on both, I said it would be wrong to figure out my views from posting it.
I think I am getting a feel for what the problem is on these threads though. People drag things from old threads over. People make assumptions of the motives and views of others. People add insults into responses, just to try to get the goat of someone else; they may not be big insults but just little digs.
And people are not taking the hint that they are skating on thin ice.
Well, they are.
I remember reading that the CO2 content in the deep ocean is so low that a shell dropped into the ocean will dissolve before it reaches the bottom. I don't know whether that's correct.
As for the calcium, I suppose it's just there in solution in sufficient quantity.
Just passin through, friend, and I mean friend. God bless you. :^)
That's the same method I use. But I suspect that your thread will last longer than some of mine ...
Care to comment on Glenn Morton's masterful examination of the Cambrian "explosion" claim, where he documents all the major phyla that are known to have developed before the Cambrian?
If one considers the Vendian/Cambrian animals as constituting the Cambrian Explosion, then we have 13 phyla appearing in the Cambrian Explosion and 20 AFTER the Cambrian Explosion. While one can assume that the 13 phyla which have no fossil record arose in the Cambrian, assumptions are NOT data. The plain fact is that the Cambrian Explosion doesn't even represent the majority of the phyla. Will these other phyla be found in the Cambrian? Maybe. But one can't rationally assume what the future holds in order to argue to his case.
And if one adds the plant phyla which appear after the Cambrian (why plant phyla should be excluded as Ray seems to imply is beyond me. They ARE phyla after all (Bohlin, 2001, p. 138)), one gets the following chart.
Period # total phyla which appear in period
(same note as above concerning phyla in the Vendian)
This yields Cambrian Explosion 13, Post-Cambrian 32! Sounds like a football score! And given that 13 phyla first appear within the past 10,000 years (having no fossil record) one could, if one wanted, claim that we are in another explosion. I wouldn't make that claim but it would fit within the data. To claim that all or even the majority of animal phyla appear in the Cambrian is demonstrably FALSE yet the claim is blindly made being repeated endlessly by apologist to apologist with no one even questioning the validity of the statement.
PS- I just got told via Freepmail that I am an Objectivist. Think my preacher will mind?
Audio(meaning of life 1.83mb)
a little late; but what the heck,keeps them out of trouble.
Why is it not possible that human knowledge/consciousness/existence will evolve to the life that the Creator established?
Scientific American is really going off the deep end. In a world covered with ice there could never have been the numerous marine life we know existed long before the Cambrian.
What the creator established is called ... creation --- what's so hard about that ?
Well, that depends. Consider Barbara Walters' interview question to Katherine Hepburn: "If you were a tree, what kind would you be?"
So, please forgive my ignorance - when the writers talk about "buffering", does this mean that they are talking about pH?
Hard to tell from the brief article above. pH buffering is one of the most common kinds of buffering, but any process (chemical or otherwise) which limits or softens the effects of something is properly called a buffer, so the paper may have been talking about something other than pH buffering.
Even in computers, message or data storage areas which temporarily store information as it's being passed from one place to another are called buffers, because they prevent data overruns from occurring if the incoming data momentarily arrives faster than it can be accepted by the destination. The memory buffer gives the data a safe place to pile up in a "traffic jam" until the "road" ahead opens up.
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