Prelims 2018 · Q60
Easy“छठा व्यापक विलोप / छठा विलोप” यह शब्द किसकी विवेचना के संदर्भ में समाचारों में प्रायः उल्लिखित होता है ?
Read this question in English
The term "sixth mass extinction/sixth extinction" is often mentioned in the news in the context of the discussion of
(a) Widespread monoculture practices in agriculture and large-scale commercial farming with indiscriminate use of chemicals in many parts of the world that may result in the loss of good native ecosystems. · (b) Fears of a possible collision of a meteorite with the Earth in the near future in the manner it happened 65 million years ago that caused the mass extinction of many species including those of dinosaurs. · (c) Large scale cultivation of genetically modified crops in many parts of the world and promoting their cultivation in other parts of the world which may cause the disappearance of good native crop plants and the loss of food biodiversity. · (d) Mankind's over-exploitation/misuse of natural resources, fragmentation/loss of natural habitats, destruction of ecosystems, pollution and global climate change.
उत्तर और व्याख्या · explanation in English
Answer: (d) मानव द्वारा प्राकृतिक संसाधनों का अतिशोषण/दुरुपयोग, प्राकृतिक आवासों का संविभाजन/नाश, पारितंत्र का विनाश, प्रदूषण और वैश्विक जलवायु परिवर्तन ।
The "sixth extinction" is the loss of species happening now, at a pace far above the natural rate, and it is driven by human activity: habitat loss and fragmentation, over-exploitation, invasive species and the like. Option (d) names these human pressures. Earlier mass extinctions were natural events, and the current one is what makes this episode different.
- ✓ (d) Species are now disappearing an estimated 100 to 1,000 times faster than before humans, and human activities are responsible. Habitat loss and fragmentation, over-exploitation, alien species and co-extinctions are the main causes.
- ✗ (b) This describes a feared natural event, a meteorite impact. The sixth extinction is not a fear about the future but an ongoing loss caused by people.
- ✗ (a) Monoculture and chemical use damage ecosystems, but they are only some of the pressures. They do not define the term, which covers the whole human-driven loss of species.
- ✗ (c) Loss of native crop varieties is a narrower concern, agricultural biodiversity. The sixth extinction is about species loss across all ecosystems.
Remember · Five natural mass extinctions came before; the sixth is human-driven, at 100 to 1,000 times the pre-human rate. The four main causes are the 'Evil Quartet'.
📘 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 “The difference is in the rates; the current species extinction rates are estimated to be 100 to 1,000 times faster than in the pre-human times and our activities are responsible for the faster rates.”
- NCERT Class 12 · Biology, Chapter 13 “The accelerated rates of species extinctions that the world is facing now are largely due to human activities. There are four major causes”
Question and answer: UPSC's official GS Paper I (2018, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink ·