> Concerning the request for a list of alternative (competing) evolutionary
>mechanisms, I will just give a sample.
>The role of natural selection is highly debated within the scientific
>Some see it as a primary creative force at all levels of evolutionary
>change, others see it as having only a stabilizing role.
>Some see evolution as more mutation-driven than selection-driven. Random
>mutation and genetic drift in small isolated populations has been given
>different weights by different workers. The role of mutation and random
>assortment of apparently nonfunctional and repeated codes in DNA is a
>significant unresolved issue. The relative roles of different types of
>genes (structural vs regulatory) and gene complexes is debated. How easy
>is it to modify regulatory genes while maintaining viability of the
>The role of the external environment in directly influencing genetic change
>has been revived. Some recent work suggests the possibility of the
>alteration of an organism's genome in response to environmental stresses.
>Related to this is that some genes subject to selection are known to
>actually promote mutation. This opens up a "neo-Lamarkian" (my term) view
>The question of contingency has also emerged as a major pint of debate.
>How "open" is evolution? To what extent are the possible evolutionary
>solutions limited? Some workers see the inherent properties of matter set
>such that the emergence of creatures fundamentally similar to ourselves was
>a near certainty.
>The developing science of complexity theory is beginning to have an
>influence in evolutionary theorizing. I will leave it to others to
>elucidate these contributions.
>Keith B. Miller
>Department of Geology
>Kansas State University
>Manhattan, KS 66506