Answer to "Guess What Species?"

Yesterday’s puzzler was to guess the species being talked about here:

One became super efficient at gobbling up its food, doing so at a rate that was about a hundred times faster than the other. The other was slower at acquiring food, but produced about three times more progeny per generation.

The answer is…

RNA molecules which self-catalyze and evolve in the lab.  This gets us one step closer to being able to show how life could have emerged on Earth without any endogenous materials (e.g. asteroids crashing into Earth carrying DNA).

I’ve never understood why such “exogenous origins” theories are popular since they seem like a pseudo-creationist punt rather than a truly scientific view.  Sure, DNA could have come from outer space.  But Stuart Kauffman showed years ago how — conceptually speaking — autocatalysis and cross-catalytic reactions could yield self-replicating molecules.  Now all that’s left is setting up the right initial conditions to show the existence proof.  No aliens — or god(s) — necessary.

  • danielhorowitz

    Very cool. But Is RNA a species?

  • “species” just means type. There is no good definition and all are flawed (except that Heng says in cellular and multicellular life we should equate species with the entire genome).

    What’s more relevant from this is that these in vitro RNA systems meet the criteria for Darwinian evolution: replication with heredity and selection. Therefore it shows plausibility that life could arise on Earth from scratch.

    BTW, I just noticed an error above, I should have said “exogenous” not “endogenous” (correcting now).

  • Lana Waggoner

    Drat! I really thought I was on to something with the Nth. Bog Lemmings. sigh. I guess the evolution – virus connection might have been too easy with all the studies and such currently being done. Interesting stuff. Thanks.