|
It's interesting to re-read some of the material on genetics and
evolution in Life, Itself. Gregor Mendel is generally considered the originator
of the field of genetic research, and yet he was apparently more interested in
the functional _expression_ of inherited properties than in what "mechanism" was
at work. The dualism between genotype and phenotype was not quite a dualism
until after Mendel died and somebody named August Weismann wrote a book called
"Das Keimplasm", in which he proposed different names for the dualism; Soma and
germplasm. Soma refers to the living organism (phenotype) and germplasm refers
to hereditary genetic material (genotype). According to Robert Rosen, Weismann
was the first to identify "life" with germplasm-- which indirectly caused the
development of the modern view of living systems, genetics, and
evolution.
So there was a shift, over the years between Mendel's work in 1866,
Weismann's in 1874, and the mid-1900's; away from seeing heredity and genetics
in functional terms and towards the view that we could learn about life and
heredity from studying genes in and of themselves; in structural and
chemical terms. Therein lies the reduction, or over-simplification, of the
concept.
In evolutionary terms, (RR, page 260, Life Itself): "...the operation of Darwinian selection pertains to phenotypes; to
soma. On the other hand, evolution itself pertains to the flow of genotypes; to
germplasm. Thus, we must regard selection on phenotypes as a modulator of this
flow of genes from one generation to the next. This is where the notion of
fitness comes in.
As presently viewed [which is your tip-off that he does
not agree with it...] , fitness involves a decision
made by natural selection about a particular soma, a particular phenotype. It is
a decision that can be imputed to the associated genotype. A low fitness rating
translates operationally into a disadvantage in populating the next generation;
in leaving offspring. Thus, a low somatic fitness serves as a filter, which
prevents the associated genotype from reaching the next generation. Thus the
gene flow is modulated, and the "gene pool" will manifest itself in somatically
fitter individuals than we started with.
On the other hand, there are no "genes" for fitness,
either. Indeed, it cannot be regarded as a somatic feature in the usual sense at
all. Fitness can only be defined operationally and retrospectively as far as
individual organisms care concerned. In particular, it cannot be fractionated
from anything. It is in fact a very mysterious concept; evolution in the
Darwinian sense would be unthinkable without it, but it has always given
evolutionists the greatest difficulty."
This looks like another closed causal loop to me, like the chicken
and the egg. They entail each other and are, in fact, part of the same
entailment loop. The only difference between heredity and evolution is actually
a unifying feature: Time. As he said on page 258; "Evolution is concerned with "explaining" the characteristics of present
generations retrospectively, in terms of the characteristics of temporally
remote ones. Heredity is concerned with what passes between one generation and
the next. Thus, if we view evolutionary processes as a kind of time integral of
hereditary ones, in which a "generation" provides the individual time-step by
which evolutionary chronicles are indexed, it is important to have a tangible
bridge between today's generation and yesterday's, the immediately preceding
one. This, roughly, is where genetics enters the picture."
It's clear that he thinks science got too caught up in the details,
and lost the correct focus. "If you chase the particles, you will chase them
right through an organism and find yourself on the other side, missing
the organism completely," he said. One must keep track of the main driver
of evolution; which is the interactivity of the system as
a whole-- in interaction with "the ambience" (environment and everything in
it). You can tell, with the phrase; "It is important to have a tangible
bridge..." In RR-speak, he was saying "It is important to reductionistic
science to have a tangible bridge..." His point of view was that genetics
only plays a set of roles, roles which change, depending on context and
multiple different roles which can all be happening simultaneously, as
is the nature of complex organization. To identify life with genetics, in his
view, is "a reduction". It's a tangent off in the wrong direction.
Evolution is a side process of life, and is hugely interactive. The term
"fitness" is entirely context dependent. So, his conclusion was that
to try and understand evolution in terms of genes/genetics alone is to
chase an imaginary wild goose through the brambles.
But it's actually worse than that; science has also tried
really hard to understand genes purely in terms of structural details
and chemistry, as if that's all there is to genetics. So this is a further
reduction. However, there may be some hope that the limitations inherent
in this approach are becoming apparent and people are actively looking for
alternate perspectives which give more purchase on the subjects at hand. Already
this year, I've read several articles in mainstream publications which speak of
the importance of "relations between genes"...
Judith
|