Read the passage carefully and give the answers to the next five questions:
Does the number of species in a community really matter to the functioning of the ecosystem? This is a question for which ecologists have not been able to give a definitive answer. For many decades, ecologists believed that communities with more species, generally, tend to be more stable than those with less species. According to the International Union for Conservation of Nature and Natural Resources (IUCN) (2004), the total number of plant and animal species described so far is more than 1.5 million.
The scientist who proved that species richness directly correlates with the stability of a community, was _____________.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → David Tilman
Option (1) Paul Ehrlich — Incorrect. Paul Ehrlich, a Stanford ecologist, gave the rivet popper hypothesis.
Option (2) David Tilman — Correct. His long-term experiments on outdoor plots linked more species with steadier and higher production.
Option (3) Robert May — Incorrect. Robert May estimated the global species diversity at about 7 million.
Option (4) Edward Wilson — Incorrect. Edward Wilson, a sociobiologist, popularised the term biodiversity.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
The Importance of Species Diversity to the Ecosystem – “… For many decades, ecologists believed that communities with more species, generally, tend to be more stable than those with less species. … A stable community should not show too much variation in productivity from year to year; it must be either resistant or resilient to occasional disturbances (natural or man-made), and it must also be resistant to invasions by alien species. We don’t know how these attributes are linked to species richness in a community, but David Tilman’s long-term ecosystem experiments using outdoor plots provide some tentative answers. Tilman found that plots with more species showed less year-to-year variation in total biomass. He also showed that in his experiments, increased diversity contributed to higher productivity.”