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About That Arsenic-Gobbling Microbe...Bad News for Darwinists?

NASA's discovery of an arsenic-ingesting microbe in California's forbidding Mono Lake looks, on the surface, like bad news for Darwinists hopeful to show what a no-big-deal it is for a planet to bring forth life unguided. The bacterium evidently uses arsenic for purposes that all other known organisms would use phosphorus, including incorporating it in DNA. A reporter for Nature News cites UC Santa Barbara geomicrobiologist David Valentine as observing that the discovery may mean "you can potentially cross phosphorus off the list of elements required for life."

That's interesting. Under Darwinian assumptions, the observation that such an alternative life chemistry is possible means that some planets previously assumed to be inhospitable to life, due to being poor in phosphorus, would now turn out after all to be potential theaters for life's presumed spontaneous arising. That would seem to bump up the number of possible dice rolls available out there to jump-start an unguided chemical and biological evolutionary process on some other planet. Yet we still have no indication from SETI or anything else that intelligent or complex life exists anywhere but here. Which makes the existence of life on earth look just a bit more special than it did before, right?

Well, maybe yes or maybe no. Astrophysicist Guillermo Gonzalez, a senior fellow with Discovery Institute's Center for Science and Culture, urges caution before drawing conclusions from the find:

I think it is too soon to be sure that arsenic can replace phosphorus in all the key cellular functions from just this study. I'll be convinced when two or three additional studies by independent groups are published backing them up. Someone is going to have to prove that this organism can thrive for many generations in a completely phosphorus-free environment to show that arsenic can substitute for phosphorus. And, if it does turn out to be true, what does this cost the organism? The results from this study indicate that the bacteria don't grow as well in the arsenic-rich solution. And, more complex organisms seem to be far more intolerant of arsenic. So, arsenic-rich, phosphate-poor planets may be limited to single-celled life.
Given Dr. Gonzalez's final point, materialists may have dodged a bullet on this after all.

Gonzalez also adds this prediction:

The enhanced fitness of the organism in an arsenic-enhanced environment compared to other organisms comes from additional chemical machinery that makes the arsenic bonds more stable. This comes at an overall cost to the organism.