Rapid speciation --
Speciation is the process of splitting a lineage and originating a new
species. A key part of speciation is the development of reproductively
isolated groups, in strict terms, groups that cannot interbreed with others
even if they had the opportunity and desire. (Mayr and others note that
Darwin never actually discussed this 'origin of species' in his book of that
name. Rather, Darwin focused on anagenesis, the *transformation* of one
species through time.)
Neo-Darwinists have a difficulty explaining the speciation process. That
is, they have difficulty justifying why increasing a reproductive barrier
would be BENEFICIAL to individuals or to the population. If the winners of
the Darwinian game are those who pass on more of their genes, then how could
a reproductive barrier possibly be any help? Population genetics, together
with strict Darwinian principles, has a difficulty here. They typically
resolve it by allowing that at some stage HARMFUL change plays a key role.
(In the currently most accepted theories of speciation, the "harmful" stage
is lessened, and implicit rather than directly discussed. For example, in
Mayr's theory the speciation is said to occur in a small sub-population,
isolated from the parent species. In those small populations the harmful
effects of inbreeding and genetic drift tend to dominate more over
selection. In such cases, neutral or even harmful mutations can rapidly be
substituted into the population.)
Currently, the speciation process at the genetic level is largely a
theoretical debate, as we lack sufficiently detailed observations of it
actually occurring. In that theoretical debate, harmful change plays a key
role (either explicitly or implicitly). In a previous post I pointed out
that evolutionists frequently brush aside harmful mutation, by automatically
assuming these will be eliminated by selection. (They also generally
ignored the issue of error catastrophe.) But harmful mutation (and perhaps
even error catastrophe) might supply a means for rapid speciation. From a
neo-Darwinian point of view, harmful mutation supplies an ingredient needed
for speciation.
For example, the doubling of chromosome number causes rapid (virtually
immediate) speciation among some plants, such as from the application of
certain chemical mutagens. (This was regularly done by growers of illicit
smoking materials because the chromosome doubling also resulted in an
increased potency of their product.) Overall such chromosome doubling is
harmful, but it can result in rapid speciation.
On a related issue. If harmful mutation and error catastrophe are important
in speciation, then it might also produce a SLOWING of the speciation rate
through time. That is, as error catastrophe slowly proceeds, the species
would gradually accumulate more harmful mutations, the mutational load would
increase, and the species would live closer to "the edge." The key
mutations necessary for speciation (and any requirement for prolonged
isolation as a small sub-population) might be enough to put organisms "over
the edge" and reduce (through non-survival) the origin of new species. In
this way, error catastrophe would result in a higher speciation rate in the
past, with a slowing as time proceeds.
Allow me a few concluding remarks. At the first sight of problems we
creationists ought not succumb to hasty suggestions of special intervention.
Like the boy who cried "Wolf!", or the feminist who over-claimed "Sexual
harassment!", or the civil right leader who over-played the "Racist!" card,
our cause suffers when we make ill-supported claims of special intervention.
Especially since the issues discussed here lately (namely, rapid rates of
genetic variation and speciation) are hardly serious problems yet. The
current state of knowledge doesn't allow anyone to mount a serious case
against creationists on these issues. Harmful mutation provides a plausible
avenue for solutions.
Walter ReMine
P.O. Box 28006
Saint Paul, MN 55128