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Author Topic: What was the Cambrian Explosion ?  (Read 5734 times)

Offline neilep

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What was the Cambrian Explosion ?
« on: 29/01/2008 23:53:01 »
*enter stage left News-Report Music*

"Derr derr derr derr derrrr derr derr naa naa na nn nerrrrrrrrrrrrr !"




Good Evening..I am Lien Nietspe and here is some late news.

Records indicate a massive explosion ,which geologists have labeled "The Cambrian Explosion" has literally just happened about a zillion years ago (no oxymorons here then !!)

What the nature of the Cambrian Explosion is has still yet to be answered.....so.....what was it ?

Further details we hope to bring you from our roving reporters out in a field somewhere !!

...and that is the end of the news.........


 

Offline JimBob

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What was the Cambrian Explosion ?
« Reply #1 on: 30/01/2008 20:43:08 »
Good evening, Lien

JimBob here from the Cambrian and you wouldn't believe your eyes. Two weeks ago there were just a few different stromatolites, a cluster of algae here and there and a small scattering of colonies of bacteria.

Now, in just TWO WEEKS! there are more phyla (and species) of animals than have ever existed and will ever exist. There are the normal things, trilobites, protocordates, and echinodems, pre-brachiopods and things that you wouldn't recognize. There are also hard sponges, shelled animals of unknown origin. Worms in shells, and a yard long carnivorous soft-bodied critter named Anomalocaris saron. Nothing like it since.

If you want to have lunch, join me and the camera crew at our camp in what will one day be Greenland.

Back to you, Lien.

In reality, there were triploblastic animals probably about a billion years ago about the size of an earthworm. ("Triploblastic" means three layered - having an ectoderm, endoderm, and mesoderm.) So there was a long period leading up to the first fossils and that is why the beginning of the Cambrian - originally defined as the beginning of life on earth - is so troublesome. It is dated by the International Stratigrphic Commission at 542 M.Y.A. (million years ago). However, trace fossils - worm tracks, molds of the shape of other organisms, etc. - are found sporatically to at least 1 billion Y.A. or the end of the Mesoproterozoic Era. The period between the latter and the beginning of the Cambrian is called the Neoprpterozoic.

I just love stratigraphers - the people who argue about these things. They are so anal. They argue about centimeters. The base of the Cambrian is defined as "2.4 m above base of Member 2 of Chapel Island Fm., Fortune Head, Burin Peninsula, southeast Newfoundland, Canada" It took years to get this established. Some wanted it lower, other higher. ANAL I tell you.

So essentially what the explosion was was an explosion of the preservation of the remains of the animals that were already alive but for one reason or another - this is another discussion - these remains were not preserved before. And it took at least 40 million years for this revolution to occur.


 

Offline neilep

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What was the Cambrian Explosion ?
« Reply #2 on: 30/01/2008 23:38:43 »
....Thank You Jim Bob ....Our Hero Geo In the Know !

Astonishing report.Yes indeed, this anchor man will indeed join you for lunch. For what you describe in all it's complex organism detail reads like a menu from my local Kazakhstan restaurant (no offense to Kazakstanians !!)

This rapidity in accelerated preservation on a scale never seen before is one for the record books. Do you think JimBob that you may be able to furnish us with a picture or two that denotes an example of the aforementioned phyla and any other subdivision or group organism ?

Thank you again .

*turns to camera*

Jimbob there....a man as old as the rocks he studies !
 

Offline JimBob

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What was the Cambrian Explosion ?
« Reply #3 on: 31/01/2008 04:03:03 »
I don't know if I can hobble over to the computer, Lian. I'll be back in two days - trip to the big city for me.
 

Offline Bass

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What was the Cambrian Explosion ?
« Reply #4 on: 03/02/2008 00:55:15 »
Lien, methinks Bobmij ventures forth to the temple of big city to discover fire??? ;D
 

Offline JimBob

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What was the Cambrian Explosion ?
« Reply #5 on: 03/02/2008 04:12:34 »
If money be fire, then yes
 

Offline JimBob

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What was the Cambrian Explosion ?
« Reply #6 on: 03/02/2008 04:16:06 »
....Thank You Jim Bob ....Our Hero Geo In the Know !

Astonishing report.Yes indeed, this anchor man will indeed join you for lunch. For what you describe in all it's complex organism detail reads like a menu from my local Kazakhstan restaurant (no offense to Kazakstanians !!)

This rapidity in accelerated preservation on a scale never seen before is one for the record books. Do you think JimBob that you may be able to furnish us with a picture or two that denotes an example of the aforementioned phyla and any other subdivision or group organism ?

Thank you again .

*turns to camera*

Jimbob there....a man as old as the rocks he studies !

Picture, I'll give you pictures - just link up to http://en.wikipedia.org/wiki/Cambrian_explosion

I especially like the picture near the bottom of Dickinsonia costata. Strange critter that. Looks like some worms I have known.
 

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What was the Cambrian Explosion ?
« Reply #6 on: 03/02/2008 04:16:06 »

 

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