Dawkins starts at the very beginning and explains the story of life and replication. Before life on earth, there still were simple compounds like water, carbon dioxide, methane and ammonia, all found in many other planets too. Chemists have put all these simple substances in a flask and supplied a source of energy such as ultraviolet light or electric sparks – artificial simulation of primordial lightning. And very soon “a weak brown soup forms containing a large number of molecules more complex than the ones originally put in.” Amino acids have been found – usually thought of as a diagnostic for the presence of life. More complex conditions yield organic substances like purines, building block of DNA itself.
“At some point a particularly remarkable molecule was formed by accident. We will call it the Replicator… it had the extraordinary property of being able to create copies of itself.” Soon we had a large population.
“But when the replicators became numerous, building blocks (in the primeval soup) must have become scarce… Some of them may even have ‘discovered’ how to break up molecules of the rival varieties chemically… others perhaps discovered how to protect themselves by building a physical wall of protein around themselves. This may have been how the first living cell appeared. Replicators began not merely to exist, but to construct for themselves containers… or survival machines.”
And then “the truth that still fills us with astonishment”: “We are survival machines – robot vehicles blindly programmed to preserve the selfish molecules known as genes… A monkey is a machine that preserves genes up trees, a fish is a machine that preserves genes in the water…”
Dawkins, Oxford professor that he is, then takes us through the details. “DNA molecules are chains of nucleotides and come in only four different kinds, whose names may be shortened to A, T, C and G. Identical in all plants and animals (the G in me is identical to the G in, say, a snail), the difference is only in “the order in which they are strung together”. And hence different survival machines for the same gene. The process how genes influence reality, through protein synthesis, is explained. Also genes work by cooperating with one other while they are competing too. For example, a carnivores animal needs the gene for sharp cutting teeth and the gene for the right kind of intestines for digesting meat.
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