The source of all multi-cellular life may turn out to be, well, poop:
Every now and then, science puts forth a theory that — at least on a bitterly cold December day, with a flu infection stirring fatigue in a certain science journalist — resonates with grand poetic truth. The theory: the incredible complexity of life on Earth, the myriad of forms and forms and functions, owes its existence to poop.
So suggested Australian geoscientist Graham Logan, one of many scientists to contemplate the mystery of Cambrian species radiation. For three billion years, life plodded along at a pace that makes glaciers look frantic; then, during the Cambrian, the major animal groups appeared. Clumps of single-celled bacteria and plankton suddenly gave way to creatures with shells, nervous systems, sensory organs and maybe even backbones.
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A decade ago, he pointed out that the first food consuming, feces-excreting organisms appeared about 40 million years before the Cambrian.
At that point, Earth’s oceans were rich in carbon and poor in oxygen. Photosynthesizing plankton produced some oxygen, but it was consumed by bacteria and offset by slow-sinking carbon. The arrival of multicellular organisms changed all that: they competed with bacteria for plankton, and their carbon-rich feces dropped quickly to the ocean floor. Bacteria dwindled; oxygen levels rose, especially in sunlit upper waters; and the ecological gates were thrown wide-open to the parade of animals that soon followed.
True ? Who knows. But that’s the great thing about science.
December 6th, 2007 at 10:55 pm
“True ? Who knows.”
Creationism. True? Who knows? That’s the great thing about faith…you can have it in something that is praised for its unknowns…or you can have it in God…who never changes.