The Great Filter

John K Clark (
Tue, 20 Aug 1996 23:23:32 -0700 (PDT)


On Tue, 20 Aug 1996 (Eric Watt Forste) Wrote:

>the jump from simple to complex single-cell life. Am I safe
>in assuming that this means the same thing as the jump from
>prokaryotic to eukaryotic life?

Yes. For two and a half billion years all you had on earth was simple
prokaryotic cell, for 700 million years after that you got much more complex
eukaryotic cells, but still no multicellular organisms. After that,
570 million years ago, the Cambrian explosion happened and things started
to get interesting.

There were multi cellular life forms called " The Ediacaran Fauna" before
the Cambrian Explosion, but it only predated it by an instant, just
100 million yeaes. All the Ediacaran fauna looked pretty much the same,
flat and soft bodied. The Tommotian Fauna was even closer to the Cambrian
Explosion, just 40 million years before, they were the first animals with
hard parts, but they also all looked much the same , blade or cup like in
this case. Neither fauna had the huge diversity that the animals in the
Cambrian Explosion had. Many, including Stephen Jay Gould think both these
faunas were failed independent experiments in multicellular life that have
no living descendants, just footnotes in the history of life, others think
they had descendants and were key to the explosion.

John K Clark

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