Posted on 02/03/2006 3:49:20 AM PST by PatrickHenry
Study suggests steps a planet must go through for complex animal life to arise.
Clay made animal life possible on Earth, a UC Riverside-led study finds. A sudden increase in oxygen in the Earth’s recent geological history, widely considered necessary for the expansion of animal life, occurred just as the rate of clay formation on the Earth’s surface also increased, the researchers report.
“Our study shows for the first time that the initial soils covering the terrestrial surface of Earth increased the production of clay minerals and provided the critical geochemical processes necessary to oxygenate the atmosphere and support multicellular animal life,” said Martin Kennedy, an associate professor of sedimentary geology and geochemistry at UCR, who led the study.
Study results appear in the Feb. 2 issue of Science Express, which provides electronic publication of selected Science papers in advance of print.
Analyzing old sedimentary rocks, the researchers found evidence of an increase in clay mineral deposition in the oceans during a 200 million year period that fell between 1.1 to 0.54 billion years ago – a stretch of time known as the late Precambrian when oxygen suddenly increased in the Earth’s atmosphere. The increases in clay formation and oxygen shortly preceded – in geological time – the first animal fossils about 600 million years ago.
“This study shows how we can use principles developed from the study of modern environments to understand the very complex origin of life on our planet – studying a time in history that has left us only a scanty record of its conditions,” said Lawrence M. Mayer, a professor of oceanography at the University of Maine and a co-author of the Science paper.
Clay minerals form in soils through biological interactions with weathering rocks and are then eroded and flushed to the sea, where they are deposited as mud. Because clay minerals are chemically reactive, they attract and absorb organic matter in ocean water, and physically shelter and preserve it.
The UCR-led study emphasizes the possibility that colonization of the land surface by a primitive terrestrial ecosystem (possibly involving fungi) accelerated clay formation, as happens in modern soils. Upon being washed down to the sea, the clay minerals were responsible for preserving more organic matter in marine sediments than had been the case in the absence of clays. Organic matter preservation results in an equal portion of oxygen released to the atmosphere through the chemical reaction of photosynthesis. Thus an increase in the burial of organic carbon made it possible for more oxygen to escape into the atmosphere, the researchers posit.
“One of the things we least understand is why animals evolved so late in Earth history,” Kennedy said. “Why did animals wait until the eleventh hour, whereas evidence for more primitive life dates back to billions of years? One of the best bets to explain the difference is an increase in oxygen concentration in the atmosphere, which is necessary for animal life and was likely too low through most of Earth’s history.”
To establish a change in clay abundance during the late Precambrian, the researchers studied thick sections of ancient sedimentary rocks in Australia, China and Scandinavia, representing a history of hundreds of millions of years, to identify when clay minerals increased in the sediment from almost nothing to modern depositional levels.
“We predicted we would only find a significant percentage of clay minerals in sediments toward the end of the Precambrian, when complex life arose, while earlier sediments would have less clay content,” Kennedy said. “This test is easier than it sounds. Because clay minerals make up the bulk of sediment deposited today, we are saying that it should be largely absent in ancient rocks. And this is just what one finds.”
The study attracted the attention of the National Aeronautics and Space Administration during the proposal stage, and the agency helped fund the research.
“NASA is interested in what conditions to look for on other planets that might lead to the arrival of life,” Kennedy said. “What are the processes? Using earth as our most detailed study site, what are the necessary steps a planet needs to go through to enable complex animal life to arise? If oxygen is the metabolic pathway, then we need to know what conditions have to allow for that to happen. The geologic record provides us with a record of these steps that occurred on Earth.”
[Author info and contact info omitted here, but it's at the end of the original article.]
Six-Fingered Clay, busy, busy, busy!!!
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"I am also formed out of clay. . ."
--Job 33:6
"And the Lord God formed man out of the dust of the ground. . ."
--Genesis 2:7
Good. That "might" means it is just a guess, just a theory. And that's the mentally sane way to express legitimate scientific ideas that are not facts.
Not to be confused with Gene Chandler:
Duke, Duke, Duke, Duke of Earl
Duke, Duke, Duke of Earl
Duke, Duke, Duke of Earl
Duke, Duke, Duke of Earl
Duke, Duke, Duke of Earl
Duke, Duke, Duke of Earl
Duke, Duke, Duke of Earl
As I walk through this world
Nothing can stop the Duke of Earl
And you, you are my girl
And no one can hurt you, oh no
Yes, I'm gonna love you
Come on let me hold you darlin'
'Cause I'm the Duke of Earl
I guess that was before he changed his named to Ali.
No surprises here.
Exactly the sequence written 3000 years ago in Genesis: One sea/one continent. Then plant life. Then oxygen and a suddenly clear atmosphere .... that revealed the sun, stars, and moon. Then animal life: starting with sea creatures and birds (dinosaurs) and (only later) mammals.
"a stretch of time known as the late Precambrian when oxygen suddenly increased in the Earth’s atmosphere."
--- If the enviro-whackos, gaia worshippers and global warming chicken littles where around then, do you think that they would have been whining about "global oxygenation"?
When all is said and done, when all knowledge about the beginnings of life is known, my personal view of all this will remain: "I believe that God created us in his own image, regardless of the amount of time it took, and it does not diminish that faith"
To me, there is no 'time line'. No one has ever stated the number of minutes or hours in a 'God-day', therefore, intelligent design and evolution are the same to me. Life cannot start from nothing.
And Gumby life and and Pokey life and ...
They just don't write stuff like that anymore.
They just don't write stuff like that anymore.
___________
See, there is a God!!
Good stuff my friend. :-)
I thought that it started when a lightening bolt hit some dirty water which produced a piece of DNA or a cell or whatever.
And then of course we ended up with Redwood trees, sharks, eagles, and people.
At least that's what they taught in school. Totally logical.
Or this:
I AM THE GOD OF HELLFIRE!
And I bring you
Fire, I'll take you to burn
Fire, I'll take you to learn
I'll see you burn
You fought hard
And you saved and earned
But all of it's going to burn
And your mind, your tiny mind
You know you've really been so blind
Now's your time burn your mind
You're falling far too far behind
Oh no, oh no, oh no
You gonna burn
Fire, to destroy all you've done
Fire, to end all you've become
I'll feel you burn
You've been living like a little girl
In the middle of your little world
And your mind, your tiny mind
You know you've really been so blind
Now's your time burn your mind
You're falling far too far behind
Fire, I'll take you to burn
Fire, I'll take you to learn
You're gonna burn
You're gonna burn
You're gonna burn, burn Burn, burn, bur
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