In comparison to temperate or polar areas, the tropics (latitudinal range of 23.5° N to 23.5° S) harbour ______ species.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → more
Species diversity is not spread evenly over the earth. The best-known pattern is the latitudinal gradient: in general, species diversity decreases as we move away from the equator towards the poles. With very few exceptions, the tropics harbour more species than temperate or polar areas, and this holds for both plants and animals.
Option (1) fewer — Incorrect. The tropics do not have fewer species. The number falls as we move away from the equator, not towards it.
Option (2) an equal number of — Incorrect. The diversity is not the same everywhere; it shows an uneven distribution with latitude.
Option (3) more — Correct. The tropics harbour more species. For example, Colombia near the equator has nearly 1,400 species of birds, while Greenland at 71° N has only 56.
Option (4) more animal species but fewer plant — Incorrect. The pattern is not split between plants and animals. A tropical forest in Ecuador has up to 10 times as many species of vascular plants as a temperate forest of equal area.
NCERT Extract:
Patterns of Biodiversity – “… In general, species diversity decreases as we move away from the equator towards the poles. With very few exceptions, tropics (latitudinal range of 23.5° N to 23.5° S) harbour more species than temperate or polar areas. Colombia located near the equator has nearly 1,400 species of birds while New York at 41° N has 105 species and Greenland at 71° N only 56 species.”