Harry Block: I’m no biologist, but how many cells do single-celled organisms have?
Ira Kane: Harry, if we’re going to be big important scientists you have to start to act the part.
I’ve been irresistibly reminded this month – ever since NASA scientists announced their work on an “arsenic-based life form” – of the 2001 movie Evolution. The story is of an alien organism that rides a flaming meteorite into the Arizona desert one night. The organism is single-celled on arrival but it evolves so rapidly that within a few days it’s bugs, it’s a bunch of big-toothed fish, it’s a hassle of dinosaurs, it’s an enormous earth-destroying giant mushroom thing.
What makes this organism so special? It’s a nitrogen-based life form! Why nitrogen? No idea. But, fortunately, the brilliant chemist in charge of the local community college’s science department, Dr. Ira Kane (David Duchovny) has nailed it. He and a geologist colleague, Harry Block (Orlando Jones) therefore call a meeting in front of – yes! – a wall chart version of the Period Table of the Elements, so that everyone can get the chemical picture.
No, really, he does. But more about that later. One of my favorite aspects of the NASA announcement – and the scientific controversy following – is that Periodic Table images have abounded. I just caught one in the Pharyngula dissection of the possibility (he thinks not) of arsenic-based life forms. Could this be a start on a better world, one in which we fly Periodic Table charts like triumphant banners?
Oops, digressing. If you haven’t heard – many times – here’s how all this started: On December 2, NASA held a press conference to announce publication of a paper by a research team, led by astrobiologist Felisa Wolfe-Simon. The scientists had developed a strain of bacteria that could thrive using arsenic rather than phosphorus, which is used by every organism on Earth to sustain life.
The implications of this – a life form based on arsenate (one arsenic atom and four of oxygen) rather than phosphate (one phosphorus atom and four of oxygen) were thrilling. As science journalist Carl Zimmer wrote for Slate, “Every living thing that scientists have ever studied uses phosphorus to build the backbone of its DNA… If the authors of the paper were right, we would have to expand our notions of what forms life can take.”
We might have to consider that across the universe, alien creatures might be bubbling up from their un-Earth-like environments, unfettered by our particular terrestrial chemistry.
Of course, on Earth, arsenate and phosphate do have well-established relationship. Arsenic is a dangerous poison because it’s structurally enough like phosphorus that the body will mistakenly take it up and circulate it into the cellular machinery. This is, in fact, the killing mechanism, allowing arsenic to infiltrate and destroy any phosphate-dependent cell that it enters. And this is the reason that NASA scientists had made a point of looking for arsenic-tolerant bacteria to begin with, hunting them down in the poison-rich waters of California’s Mono Lake.
So the NASA investigation was chemically logical. It was biologically logical. As we all know – from antibiotic resistance, if nothing else – bacteria are wonderfully adaptive, rapidly evolving creatures (although not rapidly evolving enough for a spectacularly crazed movie plot). In fact, three years ago, the National Academy of Sciences suggested that arsenic-based life might be a possibility on other worlds.
Although he acknowledged the exciting idea behind the work, Zimmer’s Slate piece was mostly a portrait of scientific unhappiness with the NASA results. The very real problem – the one that has dogged NASA since the announcement – is that many independent scientists found the experiment sloppy. This critical response is the way science works at its best, of course. Researchers announce a finding and other researchers scrutinize the work, testing its solidity. In the first few days, after the NASA paper was published, it appeared that only the agency itself was dazzled by the science.
Harry Block: Shouldn’t we call the government to help us out on this?
Ira Kane: Absolutely not! I know those people.
British science writer Ed Yong did a terrific job of chronicling the arsenic-based life story’s rise and fall on his blog, Not Exactly Rocket Science. Some scientists were especially bothered by the fact that the agency scientists didn’t entirely remove phosphorus from the solution that they used to grow the arsenic-loving bacteria; it seemed to muddy the findings. Others suggested that NASA hadn’t clearly demonstrated the presence of arsenic in bacterial structures at all.
And others suggested that part of the problem lay in the desire of space agency scientists and the journal Science, where the article was published, to hype the results. Not to mention the willingness of science journalists to swallow the hype whole. That was the point raised by Dave Munger, editor of ResearchBlogging.org, in a post for Seed magazine titled “Death of Arsenic-Based Life?” Still, Munger continues, “Despite all the misinformation and, perhaps, over-hyping of the study, the findings are still very interesting.”
And they are, if for no other reason that arsenic is a very crafty poison and any organism able to tolerate it in high doses is pretty damn fascinating. To me though, the hype, the buzz, the sense of let-down that followed the critiques, tells us something else as well. It says that we loved this story because most of us hoped it was true. We’re just here – spinning on a bright little island in the black emptiness of space. How could we not wish for other life forms, for the chemical chance of other beings spinning their own lives out on the twinkle of other planets?
Munger also points out that it’s too early to give up. All this up-and-down, back-and-forth is what eventually leads us to a really solid scientific result. And he’s right, of course. But that doesn’t mean that we don’t long occasionally for a Dr. Ira Kane who steps up to a Period Table, and just nails the alien life concept – it’s nitrogen, folks! - and, oh, by the way, uses that same arrangement of elements to save the world.
Harry Block: So, do they give the Nobel Prize out in yearly payments or is it just one lump sum, like the lottery?
Ira Kane: Let’s not get ahead of ourselves.
Harry Block: Oh, I’m not getting ahead of myself. I’m very concerned about the potential tax consequences.
See what I mean? Now that would have been a great story.
(All quotes from Evolution courtesy of IMDb)