Coevolution and species interactions

Abstract

Ecosystems are characterized by a network of interrelationships among species and species group which leads to community homeostasis. Occasional mutations or recombination in one component of the coevolving species pair may lead to a new set of defense characteristics making it possible for that component to enter a new adaptation zone from which evolutionary radiation might follow. The other component of the pair through genetic feedback might evolve to develop morphological, behavioural or biochemical features to overcome the new characteristics of the other component. Selection would carry this population to new adaptive zone allowing it to diversify further. Coevolution thus is a manifestation of selective evolutionary interactions between species or species group with a close ecological relationship. Coevolutionary instances are illustrated in plant-herbivore, host-parasite, plant-pollinator and several similar relationships. In coevolution, the biotic environment plays an active role within a relatively passive physical environment. however, change in the physical environment might favour or disfavor one component of the coevolved pair more than the other component. This differential response might lead to disruption of the relationship and may even result in loss of species.