Friday, August 15, 2008

Origin of life: Random origin of life was exploded by 1970s discovery - who didn't get the memo?

Recently, I've been reading Gerald Schroeder's The Hidden Face of God. Discussing the origin of life, he writes,
Until the mid-1970s, the accepted wisdom was that the origin of this organization that we refer to as life was the result of chance random reaction among atoms, gradually combining, one chance occurrence building upon another over eons of time until self-replication and then mutation produced the first biological cell. Three billion years were thought to have passed between the formation of liquid water on the formerly molten earth and the appearance of the first forms of life. ...

Two to three billion years was available for randomness to do its work. "Given so much time the [seemingly] impossible becomes the possible, the possible probable and the probable virtually certain. One had only to wait. Time itself [and the random reactions able to occur within those eons of time] performs the miracles." So wrote George Wald, professor of biology at Harvard University and Nobel laureate. The article appeared in the August 1954 issue of Scientific American, the most widely read science journal worldwide, the Broadway of scientific literature.

This speculation over life's origins has within it an important lesson: not to confuse accepted wisdom with revealed fact.

In the mid-1970s came the seminal discovery of Elso Barghoorn. He, like Wald, was at Harvard. Barghoorn assumed correctly that the first forms of life would be small, microbial in size. Using a scanning electron microscope, a tool able to identify minute shapes imperceptible to microscopes that probe images with visible light, Barghoorn searched the surfaces of polished slabs of stone taken from the oldest of rocks able to bear fossils. To the amazement of the scientific community, fossils of fully developed bacteria were found in rocks 3.6 billion years old. Further evidence based on fractionation between the light and heavy isotopes of carbon, a fractionation found in living organisms, indicated the origins of cellular life at close to 3,.8 billion years before the present, the same period in which liquid water first formed on Earth.

Overnight, the fantasy of billions of years of random reactions in warm little ponds brimming with fecund chemicals leading to life, evaporated. Elso Barghoorn had discovered a most perplexing fact: life, the most complexly organized system of atoms known in the universe, popped into being in the blink of a geological eye. (pp. 50-51)
Despite that, there are still people out there who believe that a random swish of chemicals is the origin of life. It's a cultural thing, I suppose. They need to believe that is true even if it can't be. It fits with the decor and the lifestyle, perhaps?

Yes, Schroeder appeared in Expelled. Book highly recommended.

(Note: Stephen E. Jones gives Wald's comment with in-line references:
"... since the origin of life belongs in the category of at-least-once phenomena, time is on its side. However improbable we regard this event, or any of the steps which it involves, given enough time it will almost certainly happen at least once ... The time with which we have to deal is of the order of two billion years. ... Time is in fact the hero of the plot. Given so much time, the `impossible' becomes possible, the possible probable, and the probable virtually certain. One has only to wait: time itself performs the miracles" (Wald, G., "The Origin of Life," Scientific American, Vol. 191, No. 2, August 1954, pp.47-48)