Posted on 06/07/2006 1:35:56 PM PDT by areafiftyone
WASHINGTON (AP) -
The best evidence yet for the oldest life on Earth is found in odd-shaped, rock-like mounds in Australia that are actually fossils created by microbes 3.4 billion years ago, researchers report.
"It's an ancestor of life. If you think that all life arose on this one planet, perhaps this is where it started," said Abigail Allwood, a researcher at the Australian Centre for Astrobiology and lead author of the new study. It appears Thursday in the journal Nature.
The strange geologic structures - which range from smaller than a fingernail to taller than a man - are exactly the type of early life astrobiologists are looking for on Mars and elsewhere.
They are known as stromatolites. They're produced layer by layer when dirt sediments mix with carbon dioxide expelled from bacteria, water, and minerals - all trapped in the microbes' sticky mucilage.
The theory is that these ancient mounds dotting a large swath of western Australia are not merely dirt piles that formed randomly into odd shapes, but that microbes built them a few billion years ago.
Some look like frosting swirls on cupcakes; others look like the inside of an egg carton. Allwood even nicknamed one 6 1/2-foot mound "crocodile back" because of its appearance.
Stromatolites have been studied for a long time, but the big question has been: Were they once teeming with life? Recently, more scientists have been leaning toward answering yes.
Allwood's research included examining thousands of the rocky mounds and grouping them into seven subtypes. It is the most comprehensive and compelling evidence that these are fossils of life, not funny-shaped rocks, according to a top expert not on her team.
"It is the best bet for the best evidence of the oldest life on Earth," said Bruce Runnegar, director of the NASA Astrobiology Institute in Moffett Field, Calif. "These are too complicated to be attributed to non-biological processes - but we don't know that for a fact."
Allwood said her study made the case for life by looking at how the stromatolites fit with the rock formations around them, with each other, and with what would have been happening on Earth at that time. One of the clinchers was categorizing them into seven repeating subtypes, which indicates they weren't random.
"It's just the sheer abundance of material and to be able to put it all in context," Allwood said.
Runnegar who has examined the mounds in western Australia several times said the first time he saw them - some of which jut out from hills at eye-level - he experienced an otherworldly feeling.
In a similar situation 10 years ago, scientists at NASA claimed they found evidence of fossilized microbial life in a Martian meteorite. Those claims have been sharply disputed and are not generally accepted.
One of the chief skeptics of the Martian meteorite claims, Ralph Harvey, a geology professor at Case Western Reserve University in Cleveland, said he is far more inclined to believe that the Australian mounds were once alive.
The key difference is that on Mars, scientists were looking for evidence of life on "a potentially dead planet" and the requirement for proof is extraordinary, Harvey said. Less evidence, he said is needed for Allwood's claims because "we already know that life has been on Earth for a very, very long time; all we're trying to do is push it further back."
Just a suggestion...
Quit lying about me, I never went to prison, just more of your lies, rumors and speculation no wonder why you believe in evolution. If someone was once on probation they must have been in prison or jail... some failed logic you have.
Just a suggestion...
No thanks, that blog is for "parodys"
Absolutely astounding placemarker.
MORE LIES!!!!! I was NEVER ARRESTED! and was never on parole.
Ah, a great film, Angels with Dirty Faces...tho Cagney was always so great in those bad guy gangster type roles, I found him to be the greatest song and dance man...I love Yankee Doodle Dandy, the way he prances on the stage...no one could ever dance like him...he was great at it, but did it very seldom in his films....
"MORE LIES!!!!! I was NEVER ARRESTED! and was never on parole."
Then why did you say you had a parole officer?
More pics...more pics...give me one from Yankee Doodle Dandy...
Since I was NEVER imprisoned I have never been on parole...
"probation officer a little different I believe."
My bad. I'll redact my post again:
As for why you were arrested, I could care less. I don't care what type of assault charge it was. That's between you and the police.
Ponder why you were suspended 3 days, for your sake.
Oh wait, I didn't have to change it this time. Cool!
If you were driving home from work and witnessed a man punching a 16 year old girl in the face maybe you would have a similar reaction? who knows in the fog of war.
Fantastic...that scene is from one of the best numbers in Yankee Doodle Dandy...thanks...
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