Which of the following are patterns of biodiversity?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (i) Latitudinal gradients, (ii) Species-area relationships.
Biodiversity is not spread evenly over the Earth. The book describes two patterns in it. In the latitudinal gradient, species diversity falls as we move from the equator towards the poles. In the species-area relationship, species richness rises with the area explored, up to a limit.
Option (1) (i) Latitudinal gradients, (ii) Species-area relationships. — Correct. Both items are the patterns of biodiversity the book names: latitudinal gradients and species-area relationships.
Option (2) (i) Latitudinal gradients, (ii) Genetic diversity. — Incorrect. Latitudinal gradient is a pattern, but genetic diversity is a level of biodiversity: the variation in genes within a species. It is not a pattern of distribution.
Option (3) (i) Species diversity, (ii) Ecological diversity. — Incorrect. Species diversity and ecological diversity are both levels of biodiversity, together with genetic diversity. They describe kinds of diversity, not how it is spread.
NCERT Extract:
Patterns of Biodiversity – “(i) Latitudinal gradients : The diversity of plants and animals is not uniform throughout the world but shows a rather uneven distribution. For many group of animals or plants, there are interesting patterns in diversity, the most well-known being the latitudinal gradient in diversity. In general, species diversity decreases as we move away from the equator towards the poles.”
Patterns of Biodiversity – “… (ii) Species-Area relationships : During his pioneering and extensive explorations in the wilderness of South American jungles, the great German naturalist and geographer Alexander von Humboldt observed that within a region species richness increased with increasing explored area, but only up to a limit.”