Prelims 2012 · archive
EasyWhich of the following can be threats to the biodiversity of a geographical area?
- 1.Global warming
- 2.Fragmentation of habitat
- 3.Invasion of alien species
- 4.Promotion of vegetarianism
Select the correct answer using the codes given below:
Answer & explanation
Answer: (a) 1, 2 and 3 only
Global warming, habitat fragmentation and invasive alien species are all established causes of biodiversity loss. Promoting vegetarianism is a dietary choice and is not one of the drivers of biodiversity decline.
- ✓ 1. Climate change has altered marine, terrestrial and freshwater ecosystems around the world. It plays an increasingly important role in the decline of biodiversity.
- ✓ 2. NCERT lists habitat loss and fragmentation as the most important cause driving animals and plants to extinction. It is the first of the four causes called the 'Evil Quartet'.
- ✓ 3. Some alien species, whether introduced deliberately or by accident, turn invasive and cause decline or extinction of native species. NCERT's example is the Nile perch in Lake Victoria.
- ✗ 4. The recognised causes are habitat loss, overexploitation, alien species invasions and co-extinctions. A dietary preference like vegetarianism is not among them.
Remember · Evil Quartet of biodiversity loss: habitat loss and fragmentation, overexploitation, alien species invasions, co-extinctions. Climate change is an added, growing threat. Vegetarianism is not a threat.
📘 Read it in NCERT: Class 12 Biology, Ch 13 (practise this chapter) · Class 12 Biology, Ch 13 (practise this chapter)
Sources
- NCERT Class 12 · Biology, Chapter 13 “Habitat loss and fragmentation: This is the most important cause driving animals and plants to extinction.”
- NCERT Class 12 · Biology, Chapter 13 “When alien species are introduced unintentionally or deliberately for whatever purpose, some of them turn invasive, and cause decline or extinction of indigenous species.”
- United Nations: Biodiversity - our strongest natural defense against climate change ↗ “climate change is playing an increasingly important role in the decline of biodiversity. Climate change has altered marine, terrestrial, and freshwater ecosystems around the world.”
Question: UPSC Civil Services (Preliminary) 2012, General Studies paper. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·