Friday, October 27, 2006

When Life Begins: No, This Isn't About Abortion

It involves something even a bit more miraculous. I mentioned a while back recently published research suggesting that the Earth already had an oxygen-rich atmosphere 3.8 billion years ago--which pushes photosynthetic life to earlier than 3.8 billion years ago. This cuts the time available for inorganic molecules to randomly, without direction, make the transition to life--and then evolve the really astonishingly sophisticated and complex ability to convert sunlight, water, and carbon dioxide into oxygen and glucose.

Now I see mentioned in the October 2006 Astronomy this new piece of evidence pushing back the first complex life to a surprisingly early stage:
Scientists studying the mysterious mounds along a 6-mile-long (10 kilometers) formation in Western Australia's Pilbara region say microbes formed the structures 3.4 billion years ago. The research, led by Australian Centre for Astrobiology doctoral student Abigail Allwood and published in the June 8 issue of Nature, challenges the idea that chemical processes formed the rocks.

Geologists call these layered features stromalites. Todays' rare examples arise as mats of microbial colonies trap and cement particles. But ancient rock rarely preserves microbes, so proving organisms formed these structures is difficult.

Allwood found seven different stromalite types. Each, she says, was part an ancient reef and occupied its own nice in that environment.

If you start at the [formation's] deep-water end and trace it along the reef system, the numbers of stromolite shapes increase and become more complex and varied, juas as occurs in biological reef systems throughout the geologic record," Allwood says. Physical and chemical processes alone can't mimic this classical environmental response.
If this is correct--and it corroborates the other evidence suggesting that life was already present 3.8 billion years ago--it creates what I call the anti-Young Earth problem.

A lot of Creationists are absolutely insistent that the Earth is only a few thousand years old, even though the Bible doesn't ever make such a claim. (Hint: taking the Bible as literally true when you are reading a translation from a langugage with less than ten thousands words in its vocabulary creates some interesting problems.) They get insistent about this because if the Earth is 10,000 years old, there's no time for evolution.

At the other end, if these pieces of evidence demonstrate that life was already of surprising complexity at 3.8 billion or 3.4 billion years ago, then evolution starts to run into problems of "not enough time" from the other end. Evolutionary theory is built on random, undirected processes, relying on mutations, the vast majority of which are lethal, and many of the rest provide no advantage.

The transition from inorganic chemicals to something capable of self-replication is a major leap--one that evolutionary biologists are wise to avoid discussing too much, because it is a major step (dare I call it a leap of faith?) that makes evolutionary advancement seem pretty simple. Then to make the leap to photosynthesis--and have microbial fossils sufficiently abundant that we manage to find examples that are 3.4 billion years old?

Remember that skeletal fossil formation requires fairly unusual geological conditions, and microbial fossil formation, because it does not involve hard materials, is even more unusual--and from that far back? For everything to fall together so that in somewhere between 700 million and 1.1 billion years we have evidence of widespread and fairly complex life on this planet implies an astonishingly rapid development for a random, undirected process reliant on a mechanism (mutuation) that more 99% of the time produces a non-viable result.

A bit less arrogance from evolutionary biologists would seem wise.

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