A Short History Of Nearly Everything by Bill Bryson

Author:Bill Bryson
Language: eng
Format: mobi, epub
Tags: sci_phys
Published: 2007-10-07T23:00:00+00:00

So what accounts for all this wondrous complexity? Well, one possibility is that perhaps it isn’t quite-not quite-so wondrous as at first it seems. Take those amazingly improbable proteins. The wonder we see in their assembly comes in assuming that they arrived on the scene fully formed. But what if the protein chains didn’t assemble all at once? What if, in the great slot machine of creation, some of the wheels could be held, as a gambler might hold a number of promising cherries? What if, in other words, proteins didn’t suddenly burst into being, but evolved.

Imagine if you took all the components that make up a human being-carbon, hydrogen, oxygen, and so on-and put them in a container with some water, gave it a vigorous stir, and out stepped a completed person. That would be amazing. Well, that’s essentially what Hoyle and others (including many ardent creationists) argue when they suggest that proteins spontaneously formed all at once. They didn’t-they can’t have. As Richard Dawkins argues in The Blind Watchmaker, there must have been some kind of cumulative selection process that allowed amino acids to assemble in chunks. Perhaps two or three amino acids linked up for some simple purpose and then after a time bumped into some other similar small cluster and in so doing “discovered” some additional improvement.

Chemical reactions of the sort associated with life are actually something of a commonplace. It may be beyond us to cook them up in a lab, à la Stanley Miller and Harold Urey, but the universe does it readily enough. Lots of molecules in nature get together to form long chains called polymers. Sugars constantly assemble to form starches. Crystals can do a number of lifelike things-replicate, respond to environmental stimuli, take on a patterned complexity. They’ve never achieved life itself, of course, but they demonstrate repeatedly that complexity is a natural, spontaneous, entirely commonplace event. There may or may not be a great deal of life in the universe at large, but there is no shortage of ordered self-assembly, in everything from the transfixing symmetry of snowflakes to the comely rings of Saturn.

So powerful is this natural impulse to assemble that many scientists now believe that life may be more inevitable than we think-that it is, in the words of the Belgian biochemist and Nobel laureate Christian de Duve, “an obligatory manifestation of matter, bound to arise wherever conditions are appropriate.” De Duve thought it likely that such conditions would be encountered perhaps a million times in every galaxy.

Certainly there is nothing terribly exotic in the chemicals that animate us. If you wished to create another living object, whether a goldfish or a head of lettuce or a human being, you would need really only four principal elements, carbon, hydrogen, oxygen, and nitrogen, plus small amounts of a few others, principally sulfur, phosphorus, calcium, and iron. Put these together in three dozen or so combinations to form some sugars, acids, and other basic compounds and you can build anything that lives.

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