Biology · Biodiversity and Conservation · NEET
They are two different things. 2.4 per cent is India's share of the world's LAND AREA (how much ground India covers). 8.1 per cent is India's share of the world's SPECIES DIVERSITY (how much life India holds). The point of the comparison is that India packs a lot of life into a small space: small land (2.4%), big life (8.1%). NTA loves to swap these two numbers, so lock them: land = 2.4, species = 8.1.
NCERT says nearly 45,000 species of plants and TWICE as many species of animals. Twice 45,000 is about 90,000 animals. So the total recorded is about 45,000 + 90,000 = 1,35,000 species. Remember the rule 'animals = 2 x plants' because the exam often gives you only the plant number and asks for animals.
A mega-diversity country is one of a small group of nations that together hold most of the Earth's species. NCERT states India is one of the 12 mega-diversity countries of the world. It earns this because of its 8.1 per cent share of global species diversity despite only 2.4 per cent of the land. Keep the number 12.
NCERT applies Robert May's estimate that only about 22 per cent of total species have been recorded so far. Using this, India probably has MORE THAN 1,00,000 plant species and MORE THAN 3,00,000 animal species yet to be discovered and named. So the recorded numbers (45,000 plants, 90,000 animals) are only a fraction of what truly exists.
Two NCERT-linked reasons help here. First, much of India's land lies in the tropical latitudes, and the tropics have the highest species diversity. Second, India has very varied habitats (Himalayas, deserts, Western Ghats, coasts, islands), giving high ecological diversity. Together these let a small land area (2.4%) hold a large share of life (8.1%).
Try the real previous-year questions from this chapter — each with the answer and a full solution.
India's share of the global species diversity is 8.1 per cent, even though India has only 2.4 per cent of the world's land area.
About 45,000 species of plants and twice as many, roughly 90,000, species of animals have been recorded in India (total about 1,35,000).
There are 12 mega-diversity countries in the world, and India is one of them, mainly because of its 8.1 per cent share of global species diversity.
Using Robert May's estimate that only about 22 per cent of species are recorded, India likely has more than 1,00,000 plant species and more than 3,00,000 animal species still to be discovered.
NEET repeatedly tests these exact figures (2.4% land, 8.1% species, 45,000 plants, twice as many animals, 12 mega-diversity countries). They are easy one-mark recall questions if the numbers and their labels are memorised correctly.
