UPSC CSE Prelims
Threats to Biodiversity Previous Year Questions (PYQs)

Detailed Explanation:

Answer: Option 4 — Mankind's over-exploitation/misuse of natural resources, fragmentation/loss of natural habitats, destruction of ecosystems, pollution and global climate change.

The term "sixth mass extinction" refers to the ongoing biodiversity crisis driven primarily by anthropogenic (human-caused) factors. Unlike previous mass extinctions caused by natural phenomena, the current extinction event is characterized by unprecedented rates of species loss due to human activities including habitat destruction, overexploitation of species, pollution, introduction of invasive species, and climate change. Scientists estimate that species are currently going extinct at rates 100 to 1,000 times higher than the natural background rate, making this a human-driven ecological catastrophe comparable to the five previous mass extinctions in Earth's 4.5-billion-year history.

📝 Short Notes: Mass Extinctions

• Current extinction rate: 100-1,000 times higher than natural background rate
• Primary drivers: Habitat loss (deforestation, urbanization), overexploitation (hunting, fishing), pollution, invasive species, climate change
• Most affected groups: Amphibians, marine mammals, large predators, island species
• IUCN Red List: Over 40,000 species currently threatened with extinction
• Holocene extinction: Another name for the sixth extinction, referring to the current geological epoch

Detailed Explanation:

✅ Statement 1 – Correct: Global warming causes climate change, leading to habitat loss, altered precipitation patterns, and species extinction due to inability to adapt to rising temperatures.

✅ Statement 2 – Correct: Habitat fragmentation divides large habitats into smaller, isolated patches, reducing genetic diversity, disrupting migration corridors, and making populations more vulnerable to extinction.

✅ Statement 3 – Correct: Invasive alien species (e.g., Lantana camara, Water hyacinth) outcompete native species for resources, disrupt ecological balance, and cause local extinctions.

❌ Statement 4 – Incorrect: Promotion of vegetarianism reduces pressure on ecosystems by decreasing demand for livestock farming, which causes deforestation and habitat destruction—thus it benefits biodiversity, not threatens it.