Question

Rank the following animal groups from greater to least (left to right) in the number of described species: Mammalia (mammals), Aves (birds), Mollusca (clams, snails, etc.), and Insecta

• A. Mollusca, Aves, Insecta, Mammalia
• B. Insecta, Mollusca, Aves, Mammalia
• C. Insecta, Aves, Mammalia, Mollusca
• D. Mammalia, Aves, Insecta, Mollusca

Hint:

Insects form the most diverse group of animals on Earth, accounting for the majority of known animal species.

Answer 1

The Correct Option is B

Different animal groups vary greatly in the number of species that have been described. Step 1: Insecta is the largest animal group, comprising more than half of all known animal species due to their high adaptability and reproductive rates.
Step 2: Mollusca is the second-largest group, including snails, clams, octopuses, and related organisms.
Step 3: Aves (birds) have fewer species compared to insects and molluscs but more than mammals.
Step 4: Mammalia has the least number of described species among the given groups. Hence, the correct descending order is: \[ \text{Insecta}>\text{Mollusca}>\text{Aves}>\text{Mammalia}. \]