UGC NET Questions (Paper – 1)

Biodiversity encompasses variation at three main levels: genetic diversity within species,species diversity within communities and ecosystem diversity across landscapes. The stem explicitly mentions diversity within species,between species and of ecosystems. This threefold description is the standard way of defining biodiversity,so the correct term is biodiversity.

Option A:
Biomagnification refers to increasing concentration of certain pollutants as they move up food chains. It is a process affecting organisms but is not a measure of variety of life. Hence it does not fit the definition in the question.

Option B:
Bioaccumulation denotes the progressive build up of substances,such as pesticides,in an organism over time. While related to ecological health,it does not capture the multiple levels of diversity specified in the stem.

Option C:
Biodiversity is the umbrella term for the total variety and variability of living organisms and the ecological complexes they form. It directly corresponds to the three dimensions of diversity mentioned,so this option correctly names the concept.

Option D:
Biodegradation is the breakdown of substances by microorganisms. It relates to waste management and nutrient cycling rather than to variation in living forms. Therefore it is not the intended concept here.

Ecologists describe biodiversity at multiple hierarchical levels to capture different kinds of variation in life. Genetic diversity refers to variation in genes within and between populations of a species. Species diversity concerns the number and relative abundance of species in a community. Ecosystem diversity encompasses the variety of habitats, communities and ecological processes within a region. Together, these three levels provide a comprehensive picture of biodiversity, making option A correct.

Option A:
Option A is correct because it reflects standard ecological classification used in textbooks and conservation planning. Protecting biodiversity means considering genes, species and ecosystems, not just counting species numbers.

Option B:
Option B is incorrect since atmospheric, hydrological and geological diversity refer to physical systems, not biological variation. While relevant to Earth science, they are not the three core biodiversity levels.

Option C:
Option C is incorrect because rural, urban and industrial categories describe types of human land use. They can influence biodiversity but are not themselves levels of biological diversity.

Option D:
Option D is incorrect as economic, political and cultural diversity are important social dimensions but lie outside the ecological framework for biodiversity.