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

Step 1: Understanding the Question
The question asks to identify the correct statements regarding the causes of biodiversity loss, commonly known as the "Evil Quartet" (Habitat loss, Over-exploitation, Alien species invasion, and Co-extinctions). Step 2: Key Formula or Approach
Evaluate each statement based on standard ecological facts: - Habitat loss: Amazon clearing. - Over-exploitation: Hunting (Sea cow). - Alien species: Nile perch (predator) vs. Water hyacinth (invasive). - Co-extinction: Symbiotic partners. Step 3: Detailed Explanation
Statement A: The Amazon is indeed being cleared for cattle ranching and soybean crops, leading to massive habitat loss. This is correct.
Statement B: Humans over-harvested Steller's sea cow and the passenger pigeon for food/oil, leading to their extinction. This is correct.
Statement C: The Nile perch is an alien predator that caused the extinction of over 200 species of native cichlid fish in Lake Victoria. It did {not} help them grow. This is incorrect.
Statement D: Water hyacinth ({Eichhornia}) is an invasive weed that clogs water bodies and depletes oxygen. This is correct.
Statement E: When a host species goes extinct, the parasites or mutualistic partners that depend on it also go extinct (Co-extinction). Thus, they {are} affected. This is incorrect.
Step 4: Final Answer
Statements A, B, and D are correct. Therefore, (B) is the right option.