To compare conservation options, judge each one against the criteria the question names, one criterion at a time, and then give a reasoned conclusion. This appears when a scenario describes a habitat under pressure and lists two or three possible actions.
It belongs to human influence on ecosystems and builds on the population ideas in explaining a limiting factor from data.
How do you compare options fairly?
- List the criteria the question gives. Do not add your own unless asked.
- Take each option and ask how it performs on criterion 1, then criterion 2, and so on.
- Record the result as yes, partly or no, with a short reason.
- Conclude by saying which option fits the stated criteria most closely, and name one thing it does not solve.
Writing the reason matters. “Partly, because it protects the forest but does not let animals reach the second fragment” earns marks; “partly” on its own does not.
Worked example
Invented scenario for practice. A forest has been split by a road into two fragments: one of 120 ha and one of 30 ha. Three options are proposed:
- Option A: Put guards on the larger fragment only.
- Option B: Plant a strip of native trees to link the two fragments.
- Option C: Breed one rare species in captivity and release it.
The criteria are: (1) protects many species, (2) allows animals to move and breed between populations, (3) keeps working without constant human effort.
| Option | Criterion 1 | Criterion 2 | Criterion 3 |
|---|---|---|---|
| A | Partly: protects the larger area only | No: the small fragment stays cut off | Partly: needs guards continuing |
| B | Yes: both fragments and the strip | Yes: animals can cross and mix | Yes: once trees grow, it works alone |
| C | No: helps one species only | No: releases do not link fragments | No: depends on ongoing breeding |
Conclusion: Option B meets all three criteria. It does not remove the road or deal with pollution, so the fragments may still face other pressures. Option A protects the core area but leaves the 30 ha fragment isolated, which can reduce gene flow and lower genetic diversity in the small population.
The mistake to watch for
A common error is to choose an option because it feels most helpful, without using the criteria.
Mistaken answer: “Option C should be chosen because saving a rare animal is most important.”
This is a personal judgement. It ignores that the criteria ask about many species and movement between populations, where Option C scores poorly.
The correction is to quote each criterion and show how the option performs. Then a preference is allowed only if the criteria support it.
Check yourself
Try these first, then open each answer.
1. Using the example above, which option meets the criterion most fully “allows animals to move and breed between populations”? Give a reason.
Show answer
Option B. The planted strip links the two fragments, so animals can cross and breed with individuals from the other population.
2. Why might a small isolated population have lower genetic diversity over time?
Show answer
There are fewer individuals to breed with and no new individuals arriving, so alleles can be lost and relatives may breed together.
3. Name one limit of captive breeding as a way to conserve a whole habitat.
Show answer
It helps only the species being bred. The habitat itself, and the other species that live in it, are not protected or restored.
Where this leads next
Once you can compare options against criteria, practise reading sample data behind such decisions in interpreting biodiversity sampling limitations, and keep opinion separate from evidence in separating environmental science evidence from political recommendations. The practice set mixes all of these.
Students who know the content but still write one-sided comparisons often need help structuring the judgement. That is a good use of time in online one-to-one Biology tuition.