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.
I'm not sure if that seminar is really going to address whether the Apex fossils are life forms. At least, the brochure doesn't explicitly say that.
Nevertheless, it puts all of Schopf's work in a poor light. But I'm not ready to throw the baby out with the bath water, not until we see what the interdisciplinary seminar hammers out next month.
But is presenting papers the sum of all they are going to accomplish in the seminar? I got the impression they were going to round-table the issues to come up with an integrated approach.
I'm almost tempted to stay up for the answer to this one. Then again, nah!
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.
LOL, course they would have to explain how these climate-stabilizing marine organisms functioned quite well in CO2 concentrations upto mid-Cambrian 7000ppm levels (over 16 times current levels) with no probs.
Late Carboniferous to Early Permian time (315 mya -- 270 mya) is the only time period in the last 600 million years when both atmospheric CO2 and temperatures were as low as they are today (Quaternary Period ).
Temperature after C.R. Scotese
Keep in mind that this is apparently a very large conference with many simultaneous events - I haven't looked through all of them to find a scheduled roundtable on pre-Cambrian fossils per se, but if you want to look, the full schedule of events is here - discussions and roundtables and cocktail hours and dinner dances and so forth are probably all going to be under the "Other Daily Events" column on the right side of the page...
Presenting papers is propably the sum of it. Usually, at these meetings, important topics will warrant a panel discussion with audience participation.
Here's another interesting one: Determining the Biogenicity of Residual Carbon within the Apex Chert
There are whole ecosystems in the deep sea vents of the world's oceans now that don't depend upon photosynthesis
I already answered that objection in the part of my post which you did not quote:
Life needs sunlight to produce the food which all life needs. And do not talk to me about chemosynthesis, because the life that existed before the Cambrian was photosynthetic bacteria.
So kindly do not repeat points which have already been refuted. Such bacteria were abundant in the period just before the Cambrian. Such life could not have survived without sunlight. So yes, the SciAm article you linked to is shameful for a magazine which claims to be scientific but no longer is now that it is under the editorship of a virulent evolutionist.
No, we can agree that the Cambrian totally disproves evolution since those species could not have gradually evolved. That means that evolution's main claim - that it can explain how species arose and change is false since it is obvious that God created the Cambrian species and that His hand in subsequent changes cannot be denied.
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