Question

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

Answer 1

Hint: Species are those that have an incredibly high effect on a certain habitat compared to their population.

Complete Answer:
- A keystone species is a species which, compared to its abundance, has a disproportionately large effect on its natural environment, a concept introduced by the zoologist Robert T. Paine in 1969.
- Such species are defined as playing a critical role in maintaining the stability of an ecological community, affecting many other organisms of the ecosystem, and helping to decide the types and numbers of various other species of the community.
- Such species are defined as playing a critical role in maintaining the ecological community stability, affecting many other ecosystem organisms, and helping to decide the types and numbers of the community's various other species.
- The ecology will be radically distinct without keystone species or cease to exist entirely. Similarly, if a keystone species is removed, an ecosystem may experience a dramatic shift even though that species was a small part of the ecosystem through biomass or productivity measurements.
- It, along with flagship and umbrella species, became a popular notion in conservation biology. Although the term is respected as a descriptor of especially close inter-species relationships and has helped ecologists and conservation policymakers to communicate more effectively, it has been criticised for oversimplifying complicated ecological processes.

So the answer is “option A”.

Note: The definition of the keystone is characterised by its ecological consequences, and these make it relevant for conservation in turn. This overlaps with many other principles in biodiversity management, such as flagship species, reference species, and umbrella species.