IB DP Biology- A4.2 Conservation of biodiversity- IB Style Questions For HL Paper 1A -FA 2025
▶️ Answer/Explanation
✅ Answer: (D) Overhunting
Question.
Which of the following best explains why many different species can live together within an ecosystem with limited resources?
(A) Each species lives in a slightly different habitat.
(B) Each species occupies a different niche.
(C) Each species inhabits a different biome.
(D) Each species makes up a different population.
(E) Each species functions at a different trophic level.
▶️Answer/Explanation
Answer: (B)
Explanation:
An ecosystem has limited resources like food, water, space, and shelter. The reason many different species can live together without direct competition wiping them out is because:
Each species occupies a different niche — their unique role or job in the ecosystem.
- A niche includes everything about how a species lives — what it eats, where it lives, when it’s active, how it interacts with other organisms, etc.
- By having different niches, species reduce competition for the same resources.
- This concept is known as resource partitioning, which allows for coexistence even in ecosystems with limited resources.
Question
A researcher is investigating the relationship between the existing species diversity in a community and the ability of an introduced nonnative species to destabilize the community. Which of the following graphs is most consistent with the claim that communities with high diversity are more resistant to change than are communities with low diversity?
▶️Answer/Explanation
Answer: (D)
Explanation:
What’s the claim?
Communities with high species diversity are more resistant to change from invading (nonnative) species.
So logically, this means:
More diversity = less survival of invaders
(The community is tougher and less likely to let outsiders thrive.)
Let’s examine the graphs:
| Option | Trend | Meaning | Conclusion |
|---|---|---|---|
| A | Flat line | Survival of invaders is unaffected by diversity | Not consistent with the claim |
| B | V-shaped | Initially declines then increases — makes no sense biologically | No |
| C | Positive slope | More diversity = more survival of invaders?? | Completely opposite |
| D | Negative slope | More diversity = less survival of invaders | Correct |