Pre-adaption 

The most subtle and most recent of biological solutions to evolutionary novelties is to invoke a process called pre-adaptation.  It is a word that seems to have two  slightly  different meanings. At its simplest, the case quoted in chapter two, of the bacteria that became antibiotic-resistant serves as an example. The few mutants that turned out to be  unaffected  by the drug are said to be pre-adapted to the catastrophic change in their environment, and were therefore able to take over an ecological niche when their fellow bacteria were wiped out. 

Pre-adaptation also means being lucky enough to inherit an organ that can be put to some different purpose later on. What use is a feather until it is a 'proper' feather? What use is a lung that is half-developed, and cannot give you enough oxygen? 

The answer comes back that if dinosaurs were warm blooded (which is nowadays increasingly thought to be the case), then rudimentary feathers instead of scales might be very useful, for they would help to conserve heat. Half a lung, or even a quarter of a lung, might be freakily useful to a fish, for the air bubble would make it more buoyant, and it would not have to put in so much effort keeping off the bottom of the water.

In other words, incipient or intermediate organs do not necessarily work in the same way as their perfected descendants. Stephen Gould gave an answer to one of the challenges listed in panel 11 (page 80) in this way: 

The first fishes did not have jaws. How could such an intricate device, consisting of several interlocking bones, ever evolve from scratch? 'From scratch' turns out to be a red herring. The bones were present in ancestors, but they were doing something else - they were supporting a gill arch located just behind the mouth. They were well designed for their respiratory role; they had been selected for this alone and 'knew' nothing of any future function. In hindsight, the bones were admirably pre-adapted to become jaws. The intricate device was already assembled, but it was being used for breathing, not eating.^l0 

This sophisticated approach towards evolutionary change has obvious uses, and offers some plausible explanations. The criticism of it that has been made is that it is too widely applied - it has become a convenient catch-all solution that is sometimes true, but also serves as a rubbish bag for all evolution's awkward odds and ends. It is hard to imagine - and certainly there is no fossil evidence for - the lucky pre-adaptations that would have twisted a bat's pelvis through 180°; or helped change the snakes salivary glands into sacs producing some of the most virulent poisons known. 

Or, to return to that puzzle of puzzles, the human eye. Here, talking about pre-adaption is simply a way of avoiding the issue, as Stephen Gould cheerfully admitted: ‘We avoid the excellent question, What good is five per cent of an eye? By arguing that the possessor of such an incipient structure did not use it for sight.'¹¹ 

But if not sight, what else? It is unreasonable to ask for a speculative evolutionary scenario for every single novel creature and organ that appears suddenly in the fossil record, but the most obvious and daunting ones continue to stare us in the face, unexplained. 

At this point a disinterested outsider might fairly conclude that evolutionary theory has reached an impasse. In three crucial areas where neo-Darwinism can be tested, it has failed:

	The fossil record reveals a pattern of evolutionary leaps rather than gradual change.
	Genes are a powerful stabilizing mechanism whose main function is to prevent new forms evolving.
	Random step-by-step mutations at the molecular level cannot explain the organized and growing complexity of life.

     Some other process it seems, must be involved - and as we shall see shortly, there are many possibilities outside the straitjacket of neo-Darwinism. 

But there is one last puzzle before coming to alternatives. ‘Natural selection’, ever since Darwin put the words, at his publisher's request, in the subtitle of The Origin of Species, has become not just biology's unifying principle, but its mantra: a phrase embodying a kind of spiritual power. 

Darwin himself endowed it with an almost metaphysical quality:  'Natural selection is daily and hourly scrutinizing every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working at the improvement of each organic being.' Ernst Mayr compared it to a sculptor, Gavin de Beer called it a master of ceremonies, George Simpson thought it like a poet or a builder, Theodosius Dobzhansky said it was similar to 'a human activity such as performing or composing music'. 

But is the phrase, at heart, empty? Is it anything more than a statement of the obvious?