Evil Quartet — Four Causes of Biodiversity Loss (NCERT)
✅ Asked in NEET 2026'The Evil Quartet' of biodiversity loss includes which of the following?
'The Evil Quartet' of biodiversity loss includes which of the following?
Match List-I with List-II and choose the correct combination. (NEET 2025) Column I A. The Evil Quartet B. Ex situ C. Lantana camara D. Dodo Column II I. Cryopreservation II. Alien species invasion III. Causes of biodiversity losses IV. Extinction
These are regarded as major causes of biodiversity loss: (NEET 2024) A. Over exploitation B. Co-extinction C. Mutation D. Habitat loss and fragmentation E. Migration Choose the correct option:
Habitat loss and fragmentation, over-exploitation, alien species invasion and co-extinction are causes for: (NEET 2022 Phase 1)
Answer & NCERT explanation
Correct answer: C — Habitat loss and fragmentation; over-exploitation; Alien species invasions; Co-extinctions
The 'Evil Quartet' refers to the four major causes of biodiversity loss: habitat loss and fragmentation, over-exploitation, alien species invasions, and co-extinctions.
Read more NCERT concept on the PYQ
Causes of biodiversity losses: The accelerated rates of species extinctions that the world is facing now are largely due to human activities. There are four major causes ('The Evil Quartet' is the sobriquet used to describe them).
The accelerated rates of species extinction the world faces now are largely due to HUMAN activities. NCERT names four major causes collectively called 'The Evil Quartet': (1) HABITAT LOSS AND FRAGMENTATION — the most important cause; tropical rainforests are destroyed for agriculture, urbanisation and other uses. (2) OVER-EXPLOITATION — humans harvest species faster than they can recover (e.g., Steller's sea cow, passenger pigeon extinct from over-exploitation). (3) ALIEN SPECIES INVASIONS — introduced species outcompete or eliminate natives (e.g., Nile perch in Lake Victoria wiped out cichlid fishes; Lantana camara; water hyacinth). (4) CO-EXTINCTIONS — extinction of one species drags down obligately associated dependents.
NEET 2026, 2025, 2024 and 2022 have repeatedly drilled the EXACT four members of the Evil Quartet. Common distractors NTA inserts to confuse students: air pollution, water pollution, soil pollution, mutation, migration and competition — NONE of these are in the Evil Quartet. Habitat loss is the SINGLE MOST IMPORTANT cause. Co-extinction is the most commonly missed member because students forget it. Lantana camara (alien) and Dodo (extinct) are paired with this concept in NEET 2025.
The Evil Quartet includes habitat loss, over-exploitation, air pollution and mutation.
Evil Quartet = (1) Habitat loss and fragmentation, (2) Over-exploitation, (3) Alien species invasions, (4) Co-extinctions. NO pollution, NO mutation, NO migration.
HOAC: Habitat loss + Over-exploitation + Alien species + Co-extinction. Pollution/mutation/migration are NOT in the quartet.
- Evil Quartet member 1: Habitat loss and fragmentation — the MOST IMPORTANT cause.
- Evil Quartet member 2: Over-exploitation (Steller's sea cow, passenger pigeon driven to extinction).
- Evil Quartet member 3: Alien species invasions (Nile perch wiping out Lake Victoria cichlids; Lantana camara; water hyacinth).
- Evil Quartet member 4: Co-extinctions — when one species goes extinct, obligately associated species also vanish.
Consider the following candidates for causes of biodiversity loss: S1: Habitat loss and fragmentation is the most important cause of biodiversity loss. S2: Over-exploitation of natural resources by humans contributes to species extinction. S3: Air pollution and water pollution are members of the 'Evil Quartet'. S4: Co-extinction occurs when extinction of one species leads to extinction of dependent obligate species. S5: Alien species invasions (e.g., Nile perch, Lantana camara) cause native species decline.
View bonus solution & explanation
Correct answer: B — S1, S2, S4 and S5
S1 CORRECT: Habitat loss and fragmentation is explicitly the MOST important cause (NCERT). S2 CORRECT: Over-exploitation is Evil Quartet member 2. S3 WRONG: Air and water pollution are NOT in the Evil Quartet — the four members are habitat loss, over-exploitation, alien species and co-extinction. NEET 2026 directly tested this trap. S4 CORRECT: Co-extinction = extinction of one species drags down obligately dependent species. S5 CORRECT: Nile perch (Lake Victoria) and Lantana camara are NCERT alien-species examples.
What is Evil Quartet?
What did NEET 2026 ask on Evil Quartet?
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Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.