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Science & Technology
When Mollusks Ruled The Earth
2007-07-31
The rise of mollusks across the globe was a harbinger of doom roughly 250 million years ago, ushering in the most devastating mass extinction in Earth's history, research now reveals.

This clammy conclusion suggests the disaster was long in coming, as opposed to the result of a more catastrophic extraterrestrial cause such as an asteroid impact, scientists added.

The largest die-off in Earth's history was not the cataclysm that ended the Age of the Dinosaurs some 65 million years ago. Instead, it was the so-called end-Permian mass extinction, which eliminated as much as 95 percent of the planet's species before even the earliest dinosaurs strode the planet.

One supposed consequence of this mass extinction was the dominance of oysters, snails and other mollusks all over the world. Now scientists studying mollusks fossils find they started rising to prominence some 8 million years before the end-Permian.

"Our results aren't really consistent with a more catastrophic extraterrestrial cause, such as an asteroid impact — although they don't directly contradict the impact theory either," said researcher Matthew Clapham at Queen's University in Kingston, Canada.

Instead, these findings support theories suggesting the end-Permian was triggered by ocean changes long in the making, "the climax of a prolonged environmental crisis," Clapham said.

The whole Permian period, stretching from about 300 million to 250 million years ago, saw gradual warming. This would have slowed down circulation in the ocean, eventually leading to very low levels of oxygen in the water. Massive volcanism near the end of the Permian might have wreaked even further havoc on the environment.

"Mollusks are better adapted to such stressful and changing environments, and so could have thrived," Clapham told LiveScience. "The abundance of mollusks we see are symptoms of the conditions that ultimately caused the extinction."

The research involved gleaning more than 33,000 Permian fossils from blocks of limestone that researchers gathered from China, Greece, Thailand, Nevada and Texas over the course of four years. These blocks were then dunked in vats of hydrochloric acid. Although the acid dissolved the limestone, over millions of years the building blocks of the fossil shells were replaced one by one with silica. This silica resisted the acid and helped the fossils survive.

"Most of the fossils were less than one centimeter in size, typically four to eight millimeters [roughly the size of an ant], so it was very delicate work to find them among all of the other detritus in the sample," Clapham recalled.

He and his colleague David Bottjer at UCLA detailed their findings online July 30 in the Proceedings of the National Academy of Sciences.
Posted by:Anonymoose

#18  The rise of mollusks across the globe was a harbinger of doom

Aaa-balone!
Posted by: Pappy   2007-07-31 22:45  

#17  I for one welcome our new mollusk masters!
Posted by: borgboy2001   2007-07-31 20:05  

#16  I assume this was another in the 'consequences of global warming' series.

So how come the Chesapeake Bay oysters are not thriving now? Are they not better adapted to such stressful and changing environments, and so could have thrived?
Posted by: Bobby   2007-07-31 17:24  

#15  The largest die-off in Earth's history was not the cataclysm that ended the Age of the Dinosaurs some 65 million years ago. Instead, it was the so-called end-Permian mass extinction, which eliminated as much as 95 percent of the planet's species before even the earliest dinosaurs strode the planet.

Man, if only I'd have gotten in on the Halliburton stock back then! I could probably drive a Toyota Prius over 100 mph, get busted for pot and a DUI and still get a slap on the wrist today, eh?
Posted by: BA   2007-07-31 14:37  

#14  All your clam chowder are belong to us!
Posted by: DarthVader   2007-07-31 13:10  

#13  We have met the enemy and they are delicious.
Posted by: Anguper Hupomosing9418   2007-07-31 13:03  

#12  Quick! Break out the melted butter and lemon juicw! If you squirt it at them it repels them!
Posted by: Deacon Blues   2007-07-31 12:08  

#11  The rise of mollusks across the globe was a harbinger of doom roughly 250 million years ago

Our weapons are useless against them! Boiling water! Melted butter! Beer batter!
Nothing can stop them! Nothing! Run for your lives!
Posted by: tu3031   2007-07-31 12:01  

#10  Nah, the song for this is Murray Head - One night in Bangkok

"One night in bangkok and the world's your oyster ..."
Posted by: bombay   2007-07-31 11:56  

#9  We should be grateful and sing!


A fish-like thing appeared among the annelids one day.
It hadn't any parapods nor setae to display.
It hadn't any eyes nor jaws, nor ventral nervous cord,
But it had a lot of gill slits and it had a notochord.

Chorus:
It's a long way from Amphioxus. It's a long way to us.
It's a long way from Amphioxus to the meanest human cuss.
Well, it's goodbye to fins and gill slits, and it's welcome lungs and hair!
It's a long, long way from Amphioxus, but we all came from there.

It wasn't much to look at and it scarce knew how to swim,
And Nereis was very sure it hadn't come from him.
The mollusks wouldn't own it and the arthropods got sore,
So the poor thing had to burrow in the sand along the shore.

He burrowed in the sand before a crab could nip his tail,
And he said "Gill slits and myotomes are all to no avail.
I've grown some metapleural folds and sport an oral hood,
But all these fine new characters don't do me any good.

(chorus)

It sulked awhile down in the sand without a bit of pep,
Then he stiffened up his notochord and said, "I'll beat 'em yet!
I've got more possibilities within my slender frame
Than all these proud invertebrates that treat me with such shame.

My notochord shall turn into a chain of vertebrae
And as fins my metapleural folds will agitate the sea.
My tiny dorsal nervous cord will be a mighty brain
And the vertebrates shall dominate the animal domain.
Posted by: Eric Jablow   2007-07-31 08:05  

#8  Since the discovery of steaming, breading, and deep-frying, the world has been safe from the mollusk threat.

Me, I just keep some cocktail sauce on hand, just in case.
Posted by: Rob Crawford   2007-07-31 07:44  

#7  

The whole Permian period, stretching from about 300 million to 250 million years ago, saw gradual warming. This would have slowed down circulation in the ocean, eventually leading to very low levels of oxygen in the water. Massive volcanism near the end of the Permian might have wreaked even further havoc on the environment.
So my neighbors' SUVs caused warming in the environment 258 million years ago?

Now THAT'S POWER! I gotta get me one of those.
Posted by: eLarson   2007-07-31 07:37  

#6  we have a world that is dominated by the nematode

Between the huge populations of both liberals and Muslims, it becomes rather clear that this world holds a superabundance of worms.
Posted by: Zenster   2007-07-31 04:10  

#5  And so now we have a world that is dominated by the nematode. Nematodes are the dominant life species on the planet if you go by numbers of them. If someone were to look at the fossil record, though, they will never see them because nematodes probably won't leave any fossils, just as any soft bodied animals without bones from that period didn't either.
Posted by: crosspatch   2007-07-31 02:52  

#4  And they were as happy as clams!

Until those nasty ammonites mussled their way in.
Posted by: Zenster   2007-07-31 02:01  

#3  The world was their oyster?

And they were as happy as clams!
Posted by: Angie Schultz   2007-07-31 01:23  

#2  Okay-y-y. so to save planet Earth and all humanity, the oysters have to be properly and righteously wiped out. Alrighty then, Global Oyster(s) Barbecue it is.
Posted by: JosephMendiola   2007-07-31 00:39  

#1  When Mollusks Ruled The Earth

The world was their oyster?
Posted by: Zenster   2007-07-31 00:13  

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