Read the paragraph and answer the Question given below:

There is no natural habitat on earth known that is inhabited just by a single species. For any species, the minimal requirement is one more species on which it can feed. Even a plant species, which makes its own food, cannot survive alone and needs soil microbes to break down the organic matter in soil and return the inorganic nutrients for absorption. It is obvious that in nature, animals, plants and microbes do not and cannot live in isolation but interact in various ways to form a biological community.

The 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 is known as:

Competition

The correct answer is Option (2) → Competition

Competition: 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.

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. Connell’s elegant field experiments showed that on the rocky sea coasts of Scotland, the larger and competitively superior barnacle Balanus dominates the intertidal area, and excludes the smaller barnacle Chathamalus from that zone. In general, herbivores and plants appear to be more adversely affected by competition than carnivores.