Question

outcomes of interspecific interactions

Answer 1

Interspecific competition usually results either in the local extinction of one of the competing species, or the two competitors will evolve differences that would allow them to avoid competition. As a result, examples of interspecific competition are relatively rare in nature, except when non-native species are introduced into an area recently, often by humans (either deliberately or inadvertently), so that one of the species has not become extinct nor have they evolved to exploit different resource.

A prime example of an introduced species competing against a native species is the introduced American gray squirrel in Great Britain, Ireland and Italy. There the grey squirrel has caused a decline in the population of the red squirrel. Another example is that of goats introduced into the Galapagos Islands causing a decline in the populations of the Galapagos tortoise. Tortoises often evolve gigantism on tropical islands because of the absence of mammalian herbivores. When goats were introduced onto the islands, they ate the island bare of vegetation, devastating the tortoise population.