Biodiversity: Definition and Significance — NEET Biology
📚 Practice ConceptIf an alien from a distant galaxy were to visit our planet Earth, the first thing that would amaze and baffle him would most probably be the enormous diversity of life that he would encounter. Even for humans, the rich variety of living organisms with which they share this planet never ceases to astonish and fascinate us. The common man would find it hard to believe that there are more than 20,000 species of ants, 3,00,000 species of beetles, 28,000 species of fishes and nearly 20,000 species of orchids. Ecologists and evolutionary biologists have been trying to understand the significance of such diversity by asking important questions– Why are there so many species? Did such great diversity exist throughout earth's history? How did this diversification come about? How and why is this diversity important to the biosphere? Would it function any differently if the diversity was much less? How do humans benefit from the diversity of life?
Which of the following statements are correct regarding the reasons for high tropical biodiversity? S1. Tropical latitudes have remained relatively undisturbed for millions of years, providing a long evolutionary time for species diversification. S2. Tropical regions experience high seasonality and unpredictable climatic conditions, which promote frequent extinction and recolonisation. S3. Greater solar energy availability in the tropics directly increases primary consumption, leading to higher biodiversity without involving productivity. S4. Temperate regions have experienced frequent glaciations in the past, reducing the evolutionary time available for speciation compared to tropical regions. S5. Long-term ecosystem experiments showed that communities with higher species diversity have greater year-to-year variation in total biomass production.
View solution & NCERT explanation
Correct answer: B — S1 and S4 only
Let's evaluate each statement concerning the reasons for high tropical biodiversity: S1: Tropical latitudes have remained relatively undisturbed for millions of years, providing a long evolutionary time for species diversification. This statement is correct. S2: Tropical environments are less seasonal, more constant, and predictable, which promotes niche specialisation, leading to greater diversity. The statement claims high seasonality and unpredictable climates, which is incorrect. S3: Higher solar energy availability in the tropics contributes to higher productivity, which *indirectly* contributes to greater diversity, not directly through increased primary consumption as stated. Therefore, this statement is incorrect. S4: Temperate regions experienced frequent glaciations in the past, leading to reduced evolutionary time for speciation compared to the stable tropical regions. This statement is correct. S5: David Tilman's long-term experiments showed that plots with more species (higher diversity) exhibited *less* year-to-year variation in total biomass, not higher variation. Therefore, this statement is incorrect. Thus, statements S1 and S4 are correct. The correct option is B.
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Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.