Question

Which of the following statements are correct? A. The Amazon rainforest being cut and cleared for cultivation of soyabeans is an example of habitat loss.
B. Steller's sea cow and passenger pigeon became extinct due to over-exploitation by humans.
C. The Nile perch introduced into Lake Victoria in East Africa helped in population growth of cichlid fish in the lake.
D. Water hyacinth is an invasive species.
E. When a species becomes extinct, the plant and animal species associated with it are not affected.

• A. B, C and D only
• B. A, B and D only
• C. A, B and E only
• D. C, D and E only

Hint:

The "Evil Quartet" includes: 1. Habitat Loss, 2. Over-exploitation, 3. Alien Species Invasion, and 4. Co-extinctions. If you see "benefit" in alien species questions, it's almost always a wrong statement!

Answer 1

The Correct Option is B

This question tests the "Evil Quartet" of biodiversity loss:
• Statement A is Correct: Habitat loss and fragmentation are the leading causes of extinction. Clearing the Amazon for soyabeans is a classic example.
• Statement B is Correct: Over-exploitation by humans led to the extinction of the Steller's sea cow and Passenger pigeon.
• Statement C is Incorrect: The introduction of the Nile perch was an "Alien Species Invasion" that led to the extinction (not growth) of more than 200 species of cichlid fish.
• Statement D is Correct: Water hyacinth (Eichhornia crassipes) is one of the most invasive weeds, known as the "Terror of Bengal."
• Statement E is Incorrect: This describes "Co-extinction." When a host species becomes extinct, its associated parasites or mutualists also face extinction. Therefore, statements A, B, and D are the only correct ones.