Statement 1: Competition is best defined as a process in which the fitness of one species (measured in terms of its ‘r’ the intrinsic rate of increase) is significantly lower in the presence of another species.

Statement 2: The Abingdon tortoise in Galapagos Islands became extinct within a decade after goats were introduced on the island, apparently due to the greater browsing efficiency of the goats.

Both statements are correct.

The correct answer is Option (1) –Both statements are correct.

Competition is best defined as a process in which the fitness of one species (measured in terms of its ‘r’ the intrinsic rate of increase) is significantly lower in the presence of another species. It is relatively easy to demonstrate in laboratory experiments, as Gause and other experimental ecologists did, when resources are limited the competitively superior species will eventually eliminate the other species, but evidence for such competitive exclusion occurring in nature is not always conclusive. Strong and persuasive circumstantial evidence does exist however in some cases. The Abingdon tortoise in Galapagos Islands became extinct within a decade after goats were introduced on the island, apparently due to the greater browsing efficiency of the goats.

Another evidence for the occurrence of competition in nature comes from what is called ‘competitive release’. A species whose distribution is restricted to a small geographical area because of the presence of a competitively superior species, is found to expand its distributional range dramatically when the competing species is experimentally removed.