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."
look at post 539.
Just because you don't get arrested(at the scene of the "crime") doesn't mean that you still don't have to go to court at a later date.
You're not supposed to have more than one screen name!
I'm not allowed to have a private blog?
We don't do it to convert the street preachers or the holier-than-thou crowd. We do it for the lurkers -- those who might be sitting on the fence or who haven't gotten a decent science education because they went to some execrable government school. The fundies are a lost cause; that doesn't mean we surrender the next generation to them.
Thanks very much for your post....You make several interesting points to ponder...
I guess we all come to these threads, some mostly willing to just read and learn, others come to argue and discuss the issues...
I am like you, when it comes to the the religious threads...I read them, but seldom ever enter into discussion on them...and they can get every bit as nasty, as any CREVO thread...but I do enjoy reading the religious threads, to see the differences in doctrines between the different religions...
I, also am no atheist...but because I support evolution, I have been called an atheist...thats really irksome...if someone wants to believe that God created everything in just 6 24hr days, then fine, do so...but for that same person to call me an atheist just because I dont believe that very same thing, is just wrong, as I see it...but there you have it...
Glad tho, that you checked into this thread, for whatever reason, and offered your views...
those that don't care for facts may not care.
I'm pretty much in the same mind set as you.
Sadly few science threads ever go past a half dozen posts before they are hijacked and turn into a brawl.
Like you I too learned several years ago to not waste my time responding to the hijackers.
This thread has now been moved to the "smoky back room." I do wonder if there had been a "science forum" in which to originally post it if it would have stayed science rather than devolve to the typical food fight.
Surely God does.
However, that particular phrase is usually the final argument I hear from those who can't defend what supposed to be God's own literal infallible account written in His own hand with lightning bolts.
There seems to be a convenient chasm of difference between unrevealed mystery and an infallible literal history.
You know, it seems that we can't often make a post on your forum about geology or zoology without it becoming a thread about theology.
Why do you think that happens?
I don't know. Guess people like to argue.
Another reason for homeschooling.
I see no reason to dignify your question with another response.
You continue to clutch at the rotting straws that line your foul den, seeking only non-arguments.
FWI
How about if you just say?
No. ^_^
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.