Biodiversity Loss and Extinction Rates — NEET Biology
📚 Practice ConceptIt is believed that communities with high diversity tend to be less variable, more productive and more resistant to biological invasions. Earth's fossil history reveals incidence of mass extinctions in the past, but the present rates of extinction, largely attributed to human activities, are 100 to 1000 times higher. Nearly 700 species have become extinct in recent times and more than 15,500 species (of which > 650 are from India) currently face the threat of extinction. The causes of high extinction rates at present include habitat (particularly forests) loss and fragmentation, over-exploitation, biological invasions and co-extinctions.
Which of the following statements are correct concerning biodiversity loss and extinction patterns? S1: Careful analysis of records indicates that extinctions across taxa are not random. S2: Among vertebrates, amphibians are currently the least vulnerable group to extinction, facing a minor threat. S3: The accelerated rates of species extinctions today are primarily due to natural evolutionary processes rather than human activities. S4: The IUCN Red List (2004) recorded the extinction of 784 species in the last 500 years, including a significant number of invertebrates. S5: Over-exploitation, alien species invasions, and co-extinctions are considered three of the 'Evil Quartet' causes of biodiversity loss.
View solution & NCERT explanation
Correct answer: C — S1, S4 and S5 only
Let's evaluate each statement based on NCERT: S1: Correct. The NCERT states, 'Careful analysis of records shows that extinctions across taxa are not random'. S2: Incorrect. The NCERT indicates the opposite, stating 'some groups like amphibians appear to be more vulnerable to extinction' and '32 per cent of all amphibian species... face the threat of extinction'. They are among the most vulnerable, not the least. S3: Incorrect. The NCERT clearly states, 'The accelerated rates of species extinctions that the world is facing now are largely due to human activities'. S4: Correct. The NCERT mentions, 'The IUCN Red List (2004) documents the extinction of 784 species (including 338 vertebrates, 359 invertebrates and 87 plants) in the last 500 years'. S5: Correct. The 'Evil Quartet' consists of four major causes of biodiversity loss: Habitat loss and fragmentation, Over-exploitation, Alien species invasions, and Co-extinctions. The statement correctly lists three of these. Therefore, statements S1, S4, and S5 are correct. The tested concept is the pattern and causes of biodiversity loss, specifically the non-random nature of extinctions and the primary threats.
What does NCERT say about It believed that communities?
Has this concept appeared in NEET?
Which chapter is this from?
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.