Question

What is a keystone species?

• A. A rare species that has minimal impact on the biomass and on other species in the community.
• B. A dominant species that constitutes a large proportion of the biomass and which affects many other species.
• C. A species, which makes up only a small proportion of the total biomass of a communities, yet has a huge impact on the communities organization and survival.
• D. A common species that has plenty of biomass, yet has a fairly low impact on the communities organization.

Answer 1

Answer: (C)

A species, which makes up only a small proportion of the total biomass of a communities, yet has a huge impact on the communities organization and survival.

Keystone species is a species, which has a significant and disproportionately large influence on the community structure and characteristics. It has often considerably low abundance and biomass as compared to dominant species. Removal or decrease in number of keystone species causes serious disruption in structure and function of community. In intertidal regions starfish feeds on mussels. Removal of starfish leads to dominance of mussel population, that excludes algae. In tropical rain forests figs function as keystone species as they provide fruit to a number of animals like birds, monkeys, bats etc during the periods of food scarcity.