Pharyngula

There’s nothing I detest more than intellectual dishonesty, and the Discovery Institute is a world leader in that. They have a ghastly little article up on their website, “Is origin of life in hot water?”, which cites a recent paper in PNAS to argue that life couldn’t have evolved without the enzymes that catalyze chemical reactions. Here’s what they say about it:

So it seems according to a new paper in the Proceedings of the National Academy of Sciences. The authors address the conundrum of origin of life chemists between the rate of (un-catalyzed) organic reactions and the lack of time available for these reactions to occur. From the article (note: an enzyme is a biological catalyst):

Whereas enzyme reactions ordinarily occur in a matter of milliseconds, the same reactions proceed with half-lives of hundreds, thousands, or millions of years in the absence of a catalyst. Yet life is believed to have taken hold within the first 25% of Earth’s history. How could cellular chemistry and the enzymes that make life possible, have arisen so quickly?” [Internal citations omitted]

Indeed this is one of the problems with origin of life scenarios, particularly those scenarios that presume a metabolism-first world (as opposed to an RNA-first world). The half-life of certain reactions without a catalyst can be millions of years, but studies show that the emergence of early bacteria could be dated as far back as 3.5 billion years (see ENV post on a cold origin of life and Schopf, J. William, “The First Billion Years: When Did Life Emerge?” Elements vol 2:229 (2006) for more on this). This means there was a limited amount of time for fundamental biological reactions to occur. Reaction kinetics can be prohibitive. However, the authors of this paper have a theory to solve the reaction kinetics problem.

No, the authors provide data to support a dramatic (and unsurprising) effect of temperature on the rate of chemical reactions, and the Discovery Institute uses a paper demonstrating the feasibility of life’s early chemistry to argue the exact opposite.

It’s stunningly arrogant — I guess they’re used to their readers simply accepting whatever they say. They quote the first three sentences of the paper, and leave off the rest of the paragraph. Would you like to know what it says?

Do you think the DI might have accurately represented the sense of the paper?

Place your bets now. Here’s the remainder of the paragraph:

Here, we show that because of an extraordinarily sensitive rela- tionship between temperature and the rates of very slow reactions, the time required for early evolution on a warm earth was very much shorter than it might appear. That sensitivity also suggests some likely properties of an evolvable catalyst, and a testable mechanism by which its ability to enhance rates might have been expected to increase as the environment cooled.

It reminds me of the infamous quote mine of the that section of Darwin’s Origin on the evolution of the eye, in which he rhetorically sets up the problem and then goes on to explain exactly how it occurred…and the creationists only ever quote the part where the problem is laid out, and pretend the answer was missing. That’s exactly what the creationists have done to this paper by Stockbridge et al. — they’ve pulled out just the few sentences at the beginning where the authors explain why this is an important problem, and then gloss over the whole point of the paper, which is to solve the problem.

Just in case you’re curious, here’s the abstract — there’s absolutely nothing in here to provide any consolation to a creationist.

All reactions are accelerated by an increase in temperature, but the magnitude of that effect on very slow reactions does not seem to have been fully appreciated. The hydrolysis of polysaccharides, for example, is accelerated 190,000-fold when the temperature is raised from 25 to 100 °C, while the rate of hydrolysis of phosphate monoester dianions increases 10,300,000-fold. Moreover, the slow- est reactions tend to be the most heat-sensitive. These tendencies collapse, by as many as five orders of magnitude, the time that would have been required for early chemical evolution in a warm environment. We propose, further, that if the catalytic effect of a “proto-enzyme”—like that of modern enzymes—were mainly enthalpic, then the resulting rate enhancement would have increased automatically as the environment became cooler. Several powerful nonenzymatic catalysts of very slow biological reactions, notably pyridoxal phosphate and the ceric ion, are shown to meet that criterion. Taken together, these findings greatly reduce the time that would have been required for early chemical evolution, countering the view that not enough time has passed for life to have evolved to its present level of complexity.


Stockbridge RB, Lewis CA, Yuan Y, Wolfenden R (2010) Impact of temperature on the time required for
the establishment of primordial biochemistry,
and for the evolution of enzymes. Proc Nat Acad Sci USA. www.pnas.org/cgi/doi/10.1073/pnas.1013647107.