Evolutionary feedback: a new mechanism for stasis and punctuated evolutionary change based on integration of the organism.
This paper argues that organisms are integrated, holistic systems whose phenotypic traits and genes interact with each other and natural selection. More than this, organisms are feedback systems. I introduce the term integration of the organism to refer to this idea that organisms are such interacting systems. Integration of the organisms is a major reason why most mutations are deleterious, and why the larger a mutation's effect, the greater the probability that a mutation will be deleterious. Yet, it is also why macromutations can occasionally be adaptive. Such adaptive mutations of large effect, an example of which is neoteny, must be coordinated with the generic system and ontogeny of the organism. Integration of the organism and the ability of both the phenotype and genotype to influence and interact with natural selection means a species can undergo sequential evolution, a term I coin in this paper to refer to a change in a trait causing a change in selection on a second trait, which leads to a change in the second trait, which in turn causes a change in selection on a third trait, changing it, and so on. Sequential evolution can sometimes result in closed feedback loops, in which a trait farther down the sequence affects a trait earlier in the sequence of traits. I call this process evolutionary feedback. Both sequential evolution and evolutionary feedback can sometimes cause punctuated evolutionary change. Evolutionary feedback can also act as a mechanism for stasis. Hence, evolutionary feedback is a mechanism for punctuated equilibrium. I propose that species to a large extent influence, even drive, their own evolution. This, of course, is not to suggest they do so willfully or consciously. It is proposed that there are three mechanisms for punctuated evolutionary change; these are described. Examples of and evidence for sequential evolution and punctuated evolution by evolutionary feedback are presented.