Darwin’s theory of natural selection explains evolution in terms of three independent factors:
1. Each living entity has a genetic memory which contains a blueprint of the organism that is manifested by its phenotype. The genetic memory and blueprint may change randomly (mutation) in an unpredictable way, leading to a change of the phenotype.
2. Genetic memory is inherited.
3. Blueprint changes affect the chances of the individual to survive in the hostile environment. Actually the environment "selects" the best fitting individuals.
The theory has little to say about the immense variability of life. It seems even to contradict itself since a selection of the fittest actually reduces variability contributed by the non-fitting who are eliminated. Selection seems to filter variability. Many properties are conserved (universal) and appear in diverse species like similar brains and limbs, and many metabolic processes. For example, roughly 15 percent of our genes are like those of bacteria, 25 percent are like those of single-celled fungi, 50 percent are like those of fruit flies, and 70 percent are like those of frogs. How might these conserved universal properties account for variability? Above all how does complex novelty, like the brain or eye arise?
In the recently published book “The Plausibility of Life: Resolving Darwin's Dilemma “, Marc W. Kirschner and John C. Gerhart introduced the theory of "facilitated variation". Structure is never inherited as such only genes (blueprint) are inherited. Suppose that when sperm and ovum unite the sperm carries a mutation in one of its genes, its effect will be constrained by the evolving embryo known as phenotype. Phenotypic variation is biased by the structure that evolves. The authors illustrate their idea by the following example. Suppose that you give a monkey a pen and paper, and let it randomly scribble, how long will it take until it writes “Monkey”? Next let the monkey hit typewriter keys, its chances to type “Monkey” will obviously improve. Finally if you let the monkey type on a computer keyboard with a spell checker that eliminates non English words, it may succeed.
Many species have conserved genetic blueprints and when their genes change (mutate) the outcome will be constrained. This is why phenotypic variation cannot be random. It is biased and creative. Kirschner and Gerhart provide interesting ideas how complexity evolves.
In a previous section the hierarchy of living complexity was defined as:
WOB(i+1) = Sum[WOB(i)]. WOB has two meanings: 1. The process set and 2. The faculty to optimally control the set. WOB is also an open system.
Whenever two living entities merge or change they are subject to this recursion. Any change (mutation) will be constrained by the WOB which emerges from this change. This recursion is a concise expression of how “facilitated variation” operates during evolution.
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