D'Abrera on Science and Philosophy

[Patrick Foley]

Ecologers,

The role of natural selection is well documented in Lepidopteran mimicry, 
crypsis and other wing pattternings. If you doubt this examine the work 
of E. B. Ford, H. Kettlewell, J. Turner and many others. This is not just 
a matter of casual observation. Lots of careful data collection and 
hypothesis testing has been done on the subject.

Evolution depends on natural selection working on whatever genetic 
variability is available, and it is certainly true that this variability 
has arisen in complex ways. Although the ultimate source of variability 
is random mutation, the mutations express themselves through 
developmental channels that have been themselves selected. Butterfly 
variants show many constraints, as may be seen by an examination of F. 
Nijhout's 1991, book The Development and Evolution of Butterfly Wing 
Patterns. 

It is no rejection of Darwin to argue that the course of evolution is 
guided by not only selection but also the patterns of genetic 
variability. In fact that is exactly what Darwin believed. To imagine 
that the genetic variability is guided by supernatural forces is to reject 
the consensus of scientists (reflected most notably in the work of Darwin, 
Lyell and Newton) that natural phenomena depend on natural laws.

patrick foley
patfoley at csus.edu