Free Republic
Browse · Search
News/Activism
Topics · Post Article

Skip to comments.

Scientists find evolution of life
EurekAlert ^ | 10/30/03

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.


TOPICS: News/Current Events
KEYWORDS: crevolist
Navigation: use the links below to view more comments.
first previous 1-20 ... 121-140141-160161-180 ... 621-639 next last
To: gore3000
Here's a frozen lake. What are these people doing, and why?


141 posted on 10/30/2003 8:20:56 PM PST by jennyp (http://crevo.bestmessageboard.com)
[ Post Reply | Private Reply | To 123 | View Replies]

To: AndrewC
Welcome back :-)
142 posted on 10/30/2003 8:21:47 PM PST by RadioAstronomer
[ Post Reply | Private Reply | To 66 | View Replies]

To: Semper
The Bible does say we will not be tempted above our rank - ability ... if you do see truth - love you will see power and evil --- the righteous will run to one and flee - eschew the other !
143 posted on 10/30/2003 8:23:00 PM PST by f.Christian (evolution vs intelligent design ... science3000 ... designeduniverse.com --- * architecture * !)
[ Post Reply | Private Reply | To 140 | View Replies]

To: Physicist
Particularly when there's a powerful heater at the bottom of the lake.

Totally false! The snow on the surface would quench any heat coming from the core! <whoa, must be channeling someone... feeling lightheaded... must go eat dinner...>

144 posted on 10/30/2003 8:23:44 PM PST by jennyp (http://crevo.bestmessageboard.com)
[ Post Reply | Private Reply | To 117 | View Replies]

To: VadeRetro; Nebullis
Sorry, but I cannot resist this! Your chart at post 88 mentions the 3.5 billion year dating which you and Nebullis and I were discussing on a previous thread. This are evidently the Schopf cyanobacterium-like pre-Cambrian fossils.

Lurkers might be interested in knowing that there is a dispute about the fossils:

Ancient Fossils or Just Plain Rock

And that dispute will be a subject of a seminar scheduled for November:

First Announcement: The Hunt for Precambrian Life: An Integrated Approach


145 posted on 10/30/2003 8:29:14 PM PST by Alamo-Girl
[ Post Reply | Private Reply | To 88 | View Replies]

To: Dales
I should point out that increasing the amount of heat energy in the atmosphere and oceans may not lead to just global heating. One could have more evaporation and snowfall leading to hotter tropics and ice covered poles. The average temperature may be hotter but the extremes more pronounced than at present. Current climate models don't predict things in this detail. Or one could have desert conditios around the equator and warm poles (this is the press's view.) Or the first scenario could lead to a higher albedo (ice and snow reflect more heat than land) and thus trigger a cooling effect. About all that is known is that more carbon dioxide and more methane in the atmosphere will lead to more solar energy deposit; what happens after that isn't so clear. (My guess is just longer summers and more violent storms.)
146 posted on 10/30/2003 8:29:53 PM PST by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
[ Post Reply | Private Reply | To 5 | View Replies]

To: Jim Robinson
That little christian wont play

knock knock
147 posted on 10/30/2003 8:31:15 PM PST by JethroHathAWay (If all you got to do is follow me around you need to chingate)
[ Post Reply | Private Reply | To 138 | View Replies]

To: f.Christian
The Bible does say we will not be tempted above our rank - ability

And is this ability not "evolving" as we experience life - both individually and as a civilization?

148 posted on 10/30/2003 8:31:22 PM PST by Semper
[ Post Reply | Private Reply | To 143 | View Replies]

To: VadeRetro
Snowcone Earth?
149 posted on 10/30/2003 8:32:03 PM PST by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
[ Post Reply | Private Reply | To 29 | View Replies]

To: Alamo-Girl
Indeed, the article is from January, 2000. Dispute over Schopf's claim of 3.5 giga-year-old cyanobacterial look-alikes dates from after that, maybe a year ago.
150 posted on 10/30/2003 8:32:59 PM PST by VadeRetro
[ Post Reply | Private Reply | To 145 | View Replies]

To: Semper
Evil is evolving !
151 posted on 10/30/2003 8:33:01 PM PST by f.Christian (evolution vs intelligent design ... science3000 ... designeduniverse.com --- * architecture * !)
[ Post Reply | Private Reply | To 148 | View Replies]

To: Doctor Stochastic
About all that is known is that more carbon dioxide and more methane in the atmosphere will lead to more solar energy deposit; what happens after that isn't so clear.

Those chaos theorists ruined everything... ;)

152 posted on 10/30/2003 8:34:06 PM PST by general_re ("I am Torgo. I take care of the place while the Master is away.")
[ Post Reply | Private Reply | To 146 | View Replies]

To: RadioAstronomer
Welcome back :-)

Well thank you very much for the welcome, but as I said to general_re, I'm just passin' through, friend. And as I also said to him, I do mean friend ;^). God bless you.

153 posted on 10/30/2003 8:35:23 PM PST by AndrewC
[ Post Reply | Private Reply | To 142 | View Replies]

To: VadeRetro
Thank you for your reply!

Indeed, I figured the Lurkers here might not have been following the previous thread and thus might not know about this upcoming seminar. I wonder how long it will be before we hear the results of it?

154 posted on 10/30/2003 8:36:24 PM PST by Alamo-Girl
[ Post Reply | Private Reply | To 150 | View Replies]

To: jennyp
whoa, must be channeling someone...

channeling - Devil's cable -- occult/EVO-(Ouija)-lution! // chaneg channels...Bible/ANTENNA -- creation!!1!

155 posted on 10/30/2003 8:36:52 PM PST by Physicist (Weird. Now I'm doing it.)
[ Post Reply | Private Reply | To 144 | View Replies]

To: CobaltBlue
Buffering means having a repository of the item being buffered. So while the carbon dioxide levels swing wildly in the atmosphere, the plankton absorb excess to keep the active amount in the atmosphere more nearly steady. It's the same idea of a buffer in an acidic solution. Or a buffer in a computer I/O system. (Not the same as a buffer to polish a car.)

Calcium just exists in the crust. (Ultimate it was produced in a nova or supernova.) Calcium is very active and comines with acids such as carbonic acid to produce limestone (and marble.)
156 posted on 10/30/2003 8:37:00 PM PST by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
[ Post Reply | Private Reply | To 41 | View Replies]

To: AndrewC
Welcome back, AndrewC - for however long you'll be staying!!!
157 posted on 10/30/2003 8:38:01 PM PST by Alamo-Girl
[ Post Reply | Private Reply | To 153 | View Replies]

To: Alamo-Girl
This part in particular hurts Schopf the most:

Brasier says his examination of the specimens revealed structures "indistinguishable from graphitic mineral growths that occur alongside [the purported fossils] - they frequently branch chaotically in the same way and intergrade continuously with the shapes of inanimate matter."
I tend to only quote Schopf now on matters rather far from his Apex chert fossils.
158 posted on 10/30/2003 8:39:29 PM PST by VadeRetro
[ Post Reply | Private Reply | To 145 | View Replies]

To: Alamo-Girl
Thanks, God bless you, Ali
159 posted on 10/30/2003 8:44:15 PM PST by AndrewC
[ Post Reply | Private Reply | To 157 | View Replies]

To: Doctor Stochastic
Buffering placemarker
160 posted on 10/30/2003 8:44:22 PM PST by Ogmios (Since when is 66 senate votes for judicial confirmations constitutional?)
[ Post Reply | Private Reply | To 156 | View Replies]


Navigation: use the links below to view more comments.
first previous 1-20 ... 121-140141-160161-180 ... 621-639 next last

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
News/Activism
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson