Which of the following statements are correct?

I. Plants have greater species diversity than animals
II. Around 3,00,000 plant species are yet to be discovered in India
III. The species diversity shown by algae is more than that of lichens
IV. There are more existing species of birds as compared to that of mammals

The correct option is C III and IV
The global inventory of biological species shows that only 22% of the existing species across the world belong to plants and fungi.

Animals occupy 70% of the total global species diversity. Thus animals have greater species diversity than plants.

Statement I is incorrect.

India is known to be the home for about 90,000 different animal species and 45,000 different plant species. Based on the estimates of Robert May, which states that only 22% of the world’s existing species have been described so far, it is believed that more than 1,00,000 plant species and 3,00,000 animal species are yet to be discovered in India.

Thus statement II is incorrect.

Considering the 22% of global species diversity exhibited by plants and fungi, the highest species diversity is shown by angiosperms (flowering plants) and fungi. This is followed by algae, mosses (bryophytes) and ferns (pteridophytes) and lichens (symbiotic associations between algae and fungi).

Thus algae shows more species diversity than lichens and Statement III is correct.

Amongst vertebrate animals, maximum species diversity is seen in the superclass Pisces (fishes), and the diversity level descends in the order - class Aves (birds) > Reptilia > Mammalia.

Thus, there are more existing species of birds as compared to that of mammals and Statement IV is correct.