Graham Cairns-Smith

molecular biologist at the University of Glasgow.^[1] He studied at the University of Edinburgh, where he gained a Ph.D. in Chemistry (1957).^[2]

crystals, preserve their external formal arrangement as they grow, snap,^{[clarification needed]} and grow further. Clay crystal masses of a particular external form may happen to affect their environment in ways that affect their chances of further replication. For example, a "stickier" clay crystal is more likely to silt a stream bed, creating an environment conducive to further sedimentation. It is conceivable that such effects could extend to the creation of flat areas likely to be exposed to air, dry, and turn to wind-borne dust, which could fall randomly in other streams. Thus—by simple, inorganic, physical processes—a selection environment might exist for the reproduction of clay crystals of the "stickier" shape.^[5]

silicates. When complex molecules perform a "genetic takeover" from their clay "vehicle", they become an independent locus of replication – an evolutionary moment that might be understood as the first exaptation