Posted: Jun 25, 2010 8:01 pm
by scruffy
CharlieM wrote:
What you're doing here is calling what amounts to a textbook definition of evolution by natural selection "unsubstantiated belief", never mind the fact that it's an observed phenomenon.

What I'm calling unsubstantiated belief is the power of evolution by natural selection to produce anything but small changes within a limited area. What observed phenomenon did you have in mind?

Your Behe quotes change nothing about what I said regarding his arguments.

I've never understood why it's so difficult for some to go from believing the evidence for short-term, multi-generational adapation via natural selection (for example, the oft quoted example of industrialized moths) to extrapolating this evidence to macro evolutionary change, over evolutionary time-spans. Although we cannot directly observe this phenomena, we can resort to broad comparisons and and direct references from such sources as the paleontological record to make some very strong inferences.

For example, we can trace the evolution of gill arches into ear ossicles and jaw musculature by looking at the ancient jawless fishes (late Triassic), and extrapolating all the way up to current day Opossums. (Wake 1979; Radinsky 1987; Luo 2007; and Francois Jacob 1977)

There are also well documented examples of laboratory recreated Macro evolution in Monkey Flowers (Mimulus). In this example, two species of flowers known to have shared a common ancestor both reproduce via pollination by insects. One species using Bees, the other Hummingbirds. These two distantly related species show some striking differences in flower shape, flower color, sexual organs, etc. all having co-evolved with their respected insect pollinators. From what I understand Schemske and Bradshaw used some modern molecular methods to to recreate this evolution in a controlled laboratory experiment. (Schemske and Bradshaw 1999; Bradshaw and Schemske 2003).

It is one thing to change the color of a moth, and quite another creating an ear ossicle from jaw arches, that I'll give you. One needs to keep in mind though that the former occured over a time-span of a few generations with the latter taking place over the span of millions of years. Cumulative selection over geological time spans is a powerful force, one that us humans are quite incapable of being able to understand. This is what makes studies and evidence like the above so important to our understanding of adaptations via natural selection.


EDIT: On a side note, from what I seem to have gathered here is that you (CharlieM) have no problem with limited forms of micro evolutionary change, but reject the notion of macro evolution. My question is what exactly DO you think to be the cause of all the diversity and change in life we see around us?