Another puzzle piece?
In his 1986 book The Blind Watchmaker, Richard Dawkins argued that the origins of life were no longer as mysterious as they once appeared. He suggested that life began with inorganic crystals, which spontaneously stack new materials into a shape determined by their “seed.” Two crystals built out of the same raw materials, introduced into the same environment, will compete for those resources; the one with the superior stacking technique absorbs and destroys the loser. This kind of “natural selection” among crystals has produced the geometric crystal shapes we see today–less efficient stacking forms were weeded out in this competition.
Certain kinds of inorganic crystals attract the building blocks of organic matter, weaving them into their stacking patterns to create simple protein shapes. At some point, says Dawkins, a crystal stacked in such a way that the protein shape it created–only a side effect–could continue to absorb new protein materials and stack them on its own. (He wrote this before prions were discovered, but this hypothetical first living thing sounds an awful lot like a prion, a single rogue protein molecule that dissassembles your useful proteins and turns them into copies of itself.)
Now, this goes a way towards explaining the origins of life, but it doesn’t explain a second mystery: sexual reproduction. Asexual reproduction is so much more successful–think of how many simple single-celled creatures there are, compared to multi-celled colonies of sexual creatures like us. The traditional answer is that sexual reproduction leads to greater complexity through mutation. (Introduce some sexually-reproducing single-celled creatures to the right environment, give them enough time, and they will turn into elephants. With asexual creatures, they’ll stay pretty much the same.) But mutation has great risks, and complex organisms are more prone to breakdowns. Where is the reward?
Maybe it’s here. Scientists examining the Chernobyl mutations have found that several species of area worms have begun to change over from asexual to sexual reproduction. That in itself isn’t remarkable–I seem to recall that a bunch of creatures can switch their own gender after the fact, including frogs and the mutant dinosaurs from Jurassic Park. But the number of sexually reproducing worms in the Chernobyl area keeps increasing, year after year, while the asexuals die out. The theory is that a mutation produced by sexual reproduction is making them more resistant to radiation.
Yay for our side, I guess. ‘Course, it was us complex organisms that irradiated the little guys in the first place….