Biology Reference
In-Depth Information
Unlike the impression created by Statement 14.5, DNA is not the whole solution
to the problems of evolution but only a part of the solution. According to the so-
called
Kirschner-Gerhart thesis
, Statement 14.6 given in Sect.
14.2
, the complete
solution to the evolutionary problems may lie in our understanding
how the living
cell works
.
14.2 The Cell Theory of Evolution
There is no doubt that
evolution
results from complex interactions between
organisms and their environment over the geological time scale. Evolution
implicates a system of complex interactions that may be schematically represented
as in Fig.
14.1
.
If Fig.
14.1
is valid, the evolving phenotype (i.e., evolution) is a function of three
variables that are irreducible.-
1. The genotype at time n that varies among different individuals of a group.
2. Environmental conditions that change from n to (n + 1) with speeds much
slower than the lifetime of individual organisms, and
3. Mechanisms of interactions between individual organisms and their environ-
ment constrained by developmental mechanisms. That is, organisms are
postulated to be genetically endowed with the capacity to survive only within
a fixed range of environmental conditions and die otherwise.
Variables (1) and (3) are determined by
cell biology
and variable (2) by
geology
.
The scheme shown in Fig.
14.1
may thus be viewed as a diagrammatic representa-
tion of the
cell biology of evolution
that seems consistent with the prediction made
by M. Kirschner and J. Gerhart (1997):
...
with the explosion in molecular biology, cell biology could assert itself in evolutionary
thought and allow a reinterpretation of evolution as a cellular process.
(14.6)
Phenotype (n)
EVOLUTION =
Phenotype (n + 1) Mechanism
Env: n → (n + 1)
Fig. 14.1 A diagrammatic representation of the biological evolution. Evolution is viewed as
the emergence of cell phenotype (n + 1) from cell phenotype (n) as the result of the interaction
between the cell (symbolized by the
triangle
) and the environment as Environment (n) changes
to Environment (n + 1) (Notice that this diagram is similar to [or isomorphic with] the diagram
processes)
