Facilitated variation
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.
http://www.what-is-cancer.com/papers/EvolutionNewPerspective.html
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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