In this thread, I hope to explore a consequence of Intelligent Design
theory which is seldom discussed: parallel interventions.
Last year on the evolution@calvin mailing list I posted the following
questions (slightly modified):
Suppose we are examining a complex biological feature which we
suspect could not have evolved, but required intelligent
intervention. Now suppose this feature is found in multiple groups
or organisms whose common ancestors go back well before the first
appearance of that feature (e.g. bat wings and bird wings). Should
we hypothesize that, historically, multiple instances of intervention
took place to achieve similar features in each group? Does this seem
less elegant than a single (historical) intervention? Should we
hypothesize a single intervention with a very long dormancy? Or
would this pattern suggest to us that, perhaps, that *particular*
feature probably arose through natural mechanisms? If so, why?
In particular, consider the marsupials. The isolation of marsupials
to Australia (and nearby islands) --- combined with fossils which
record a divergence between marsupials from other mammals at the
same time as Australia became separated from the continent --- strongly
suggest that the creator used *some* degree of genealogical
continuity to create modern marsupials. There are many different
species of marsupials, covering a wide variety of climates, ecological
niches, and survival strategies. Their distribution into these niches
parallels, on a smaller scale, the distribution of non-marsupial mammals
on other continents.
Here, then, is the nub of my question for intelligent design theorists:
Do you think the wide variety of marsupials could have evolved, or do
you think that such a wide variety of anatomies and adaptations is
beyond evolution's capabilities?
If your conclusion is that the wide variety of anatomies and adaptations
found in marsupials could not have evolved, then it seems to follow that
there must have been separate and parallel interventions in the
marsupial and non-marsupial mammal populations, in order to achieve very
similar adaptations in each population.
No doubt this pattern is repeated in many different places, in many
different groups of plants and animals: A complex adaptation to a
particular environment or ecological niche is found in isolated
populations whose common ancestors predate the development of those
adaptations. (e.g. bat wings and bird wings) So the hypothesis that a
particular biological feature is too complex to evolve necessarily entails,
in many cases, the hypothesis of multiple, parallel interventions in
isolated populations (to achieve essentially the same biological effect).
This poses, at a minimum, an aesthetic challenge ID theory. I would
appreciate others' thoughts on this topic.