Question

Identify the major threats to Biodiversity, that is, the evil quartette from the following:
I. Invasion of local species
II. Over exploitation
III. Introduction of alien species
V. Habitat loss
VII. Co-extinction

• A. I, III, VI, VII
• B. I, II, V, VII
• C. II, III, V, VII
• D. III, IV, VI, VII

Hint:

Habitat loss is the number one cause of species extinction worldwide.
Fragmentation divides large habitats into smaller patches, which particularly harms large mammals and migratory birds.

Answer 1

The Correct Option is C

Step 1: Recall the concept being tested.
Ecologists group the major man made causes of extinction under one label, the Evil Quartet. Getting this list right is really just memory work once you know the four items.
Step 2: List the four accepted causes.
They are habitat loss and fragmentation, over exploitation of species, invasion by alien species, and co-extinction, when a species disappears along with another it depended on. Invasion of local species is not part of this set.
Step 3: Match against the roman numerals given.
From the list in the question, II (over exploitation), III (introduction of alien species), V (habitat loss) and VII (co-extinction) line up exactly with the four accepted causes, while I (invasion of local species, really the reverse idea) does not belong.
Final answer: Option 3, II, III, V, VII, the four components of the Evil Quartet.