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pscot Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-16-09 05:14 PM
Original message
Good news on the extinction front
Earth will probably get over us quicker than expected.

http://www.sciencedaily.com/releases/2009/09/0909021223...

Recovery Of Ammonoids After Most Massive Extinction Of All Time
ScienceDaily (Sep. 14, 2009) After the End-Permian extinction 252.6 million years ago, ammonoids diversified and recovered 10 to 30 times faster than previous estimates. The surprising discovery raises questions about paleontologists' understanding of the dynamics of evolution of species and the functioning of the biosphere after a mass extinction.

The study, conducted by a Franco-Swiss collaboration involving the laboratories Biogosciences (Universit de Bourgogne / CNRS), Paloenvironnements & Palobiosphre (Universit Claude Bernard / CNRS) and the Universities of Zurich and Lausanne (Switzerland), appears in the August 28 issue of Science.

The history of life on Earth has been punctuated by a number of mass extinctions, brief periods of extreme loss of biodiversity. These extinctions are followed by phases during which surviving species recover and diversify. The End-Permian extinction, which took place between the Permian (299 252.6 MY) and Triassic (252.6 201.6 MY), is the greatest mass extinction on record, resulting in the loss of 90% of existing species. It is associated with intensive volcanic activity in China and Siberia. It marks the boundary between the Paleozoic and Mesozoic Eras. Until now, studies had shown that the biosphere took between 10 and 30 million years to recover the levels of biodiversity seen before the extinction.

Ammonoids are cephalopod swimmers related the nautilus and squid. They had a shell, and disappeared from the oceans at the same time as the dinosaurs, 65 million years ago, after being a major part of marine fauna for 400 MY.

The Franco-Swiss team of paleontologists has shown that ammonoids needed only one million years after the End-Permian extinction to diversify to the same levels as before. The cephalopods, which were abundant during the Permian, narrowly missed being eradicated during the extinction: only two or three species survived and a single species seems to have been the basis for the extraordinary diversification of the group after the extinction. It took researchers seven years to gather new fossils and analyze databases in order to determine the rate of diversification of the ammonoids. In all, 860 genera from 77 regions around the world were recorded at 25 successive time intervals from the Late Carboniferous to the Late Triassic, a period of over 100 million years.

The discovery of this explosive growth over a million years takes a heated debate in a new direction. Indeed, it suggests that earlier estimates for the End-Permian extinction were based on truncated data and imprecise or incorrect dating. Furthermore, the duration for estimated recovery after other lesser extinctions all vary between 5 and 15 million years.

The result obtained here suggests that these estimates should probably be revised downwards. The biosphere is most likely headed towards a sixth mass extinction, and this discovery reminds us that the recovery of existing species after an extinction is a very long process, taking several tens of thousands of human generations at the very least.

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eleny Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-16-09 05:16 PM
Response to Original message
1. I'm ahsamed that I had to look up "ammonoids"
But when I saw the pictures I thought, "Oh, those cute little guys!"

:hi:
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stopbush Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-16-09 05:17 PM
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2. Isn't science great? To have the ability to increase our knowledge set.
Just think about it. How many human enterprises offer such a boon to the human condition?
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Nederland Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-16-09 06:13 PM
Response to Reply #2
7. Increasing our knowledge is impossible
The sum total of all truth was written down in the Bible long ago.

Or didn't you get the memo? :eyes:
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DCKit Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-16-09 05:34 PM
Response to Original message
3. Thank Dog and FSM. I was really beginning to sweat that whole "Global Warming" scam.
Knowing that some lower life-forms might recover after only a million or so years really puts my tiny mind at ease.
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pscot Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-16-09 05:43 PM
Response to Reply #3
4. That was my thought, exactly.
I think it was Kafka who said, There is hope, but not for us.
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phantom power Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-16-09 05:46 PM
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5. Surely, the *new* biosphere will thank us!

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pscot Donating Member (1000+ posts) Send PM | Profile | Ignore Wed Sep-16-09 06:10 PM
Response to Reply #5
6. Max Baucus, right?
He'll be bringing his keen intellect and finely honed consensus building skills to the climate bill next.
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