hypothesis-that macromutations occur in large numbers, making
the emergence of new species possible-conflicts with known
facts of genetics.
One rule, put forward by R.
A. Fisher, one of the last century's best known geneticists,
and based on observations, clearly invalidates this hypothesis.
Fisher states in his book The Genetical Theory of Natural
Selection that the likelihood that a particular mutation
will become fixed in a population is inversely proportional
to its effect on the phenotype.175 Or,
to put it another way, the bigger the mutation, the less chance
it has of becoming a permanent trait within the group.
It is not hard to see the reason for this. Mutations,
as we have seen in earlier chapters, consist of chance changes
in genetic codes, and never have a beneficial influence on
organisms' genetic data. Quite the contrary: individuals affected
by mutation undergo serious illnesses and deformities. For
this reason, the more an individual is affected by mutation,
the less chance it has of surviving.
Ernst Mayr, the doyen of Darwinism, makes this
comment on the subject:
The occurrence of genetic
monstrosities by mutation … is well substantiated, but they
are such evident freaks that these monsters can be designated
only as 'hopeless'. They are so utterly unbalanced that
they would not have the slightest chance of escaping elimination
through stabilizing selection … the more drastically a mutation
affects the phenotype, the more likely it is to reduce fitness.
To believe that such a drastic mutation would produce a
viable new type, capable of occupying a new adaptive zone,
is equivalent to believing in miracles … The finding of
a suitable mate for the 'hopeless monster' and the establishment
of reproductive isolation from the normal members of the
parental population seem to me insurmountable difficulties.176
It is obvious that mutations cannot bring about
evolutionary development, and this fact places both neo-Darwinism
and the punctuated equilibrium theory of evolution in a terrible
difficulty. Since mutation is a destructive mechanism, the
macromutations that proponents of the punctuated equilibrium
theory talk about must have "macro" destructive effects. Some
evolutionists place their hopes in mutations in the regulatory
genes in DNA. But the feature of destructiveness which applies
to other mutations, applies to these, as well. The problem
is that mutation is a random change: any kind of random change
in a structure as complex as genetic data will lead to harmful
Two famous proponents of the
punctuated evolution model: Stephen Jay Gould and Niles
In their book The Natural Limits to Biological
Change, the geneticist Lane Lester and the population
biologist Raymond Bohlin describe the blind alley represented
by the notion of macromutation:
The overall factor that
has come up again and again is that mutation remains the
ultimate source of all genetic variation in any evolutionary
model. Being unsatisfied with the prospects of accumulating
small point mutations, many are turning to macromutations
to explain the origin of evolutionary novelties. Goldschmidt's
hopeful monsters have indeed returned. However,
though macromutations of many varieties produce drastic
changes, the vast majority will be incapable of survival,
let alone show the marks of increasing complexity. If
structural gene mutations are inadequate because of their
inability to produce significant enough changes, then regulatory
and developmental mutations appear even less useful because
of the greater likelihood of nonadaptive or even destructive
consequences… But one thing seems certain: at present, the
thesis that mutations, whether great or small, are capable
of producing limitless biological change is more an article
of faith than fact.177
Observation and experiment both show that mutations
do not enhance genetic data, but rather damage living things.
Therefore, it is clearly irrational for proponents of the
punctuated equilibrium theory to expect greater success from
"mutations" than the mainstream neo-Darwinists have found.
175 R. A. Fisher,
The Genetical Theory of Natural Selection, Oxford
University Press, Oxford, 1930.
176 Ernst Mayr, Populations, Species,
and Evolution, Belknap Press, Cambridge, 1970, p. 235.
177 Lane P. Lester, Raymond G. Bohlin, The
Natural Limits to Biological Change, Probe Books, Dallas,
1989, pp. 141-142. (emphasis added)