Populations and Sustainability | OCR A-Level Biology A (H420)
Populations and Sustainability
- 52 questions
- 5 subtopics
- Module 6: Genetics, evolution and ecosystems
- Component 02 and Component 03
Populations and sustainability closes Module 6.
It covers what sets the size of a population and its carrying capacity, predator and prey cycles, competition within and between species, the difference between conservation and preservation, sustainable timber and fishing, and how human impacts are controlled.
Sample questions from Populations and Sustainability
Answer each one closed book first, then open the answer.
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Population size and limiting factors
What is meant by carrying capacity?
Show the answer
Carrying capacity is the maximum population size that an environment can sustain indefinitely given the available resources. -
Population size and limiting factors
How can mineral ion availability limit a population?
Show the answer
Mineral ions are needed for synthesising essential molecules (e.g. proteins, nucleic acids); deficiency restricts growth and reproduction. -
Predator-prey cycles and competition
Describe the characteristic pattern seen in predator-prey population graphs.
Show the answer
Both populations show oscillations over time, with predator population peaks lagging behind prey population peaks. -
Predator-prey cycles and competition
Why does the predator population peak after the prey population?
Show the answer
Predator numbers rise only once prey are abundant enough to support breeding, so their peak lags behind. -
Conservation and preservation
Give an economic reason for conservation related to industries.
Show the answer
Conservation maintains resources for industries such as fishing, timber, and tourism, ensuring long-term economic benefits. -
Conservation and preservation
Why is education considered a social reason for conservation?
Show the answer
Conserved ecosystems provide opportunities for scientific research and environmental education. -
Sustainable timber production and fishing
Why is replanting important in sustainable timber production?
Show the answer
Replanting replaces harvested trees, maintaining forest cover and ensuring a continuous supply of timber for the future. -
Sustainable timber production and fishing
Explain how larger mesh sizes in fishing nets promote sustainability.
Show the answer
Larger mesh sizes allow immature fish to escape, enabling them to reach reproductive age and maintain the breeding population.
The 5 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Population size and limiting factors | Birth rate, death rate, immigration and emigration, and the abiotic and biotic limiting factors that set the carrying capacity of an environment. | 16 |
| Predator-prey cycles and competition | The lag between predator and prey numbers and the pattern it produces on a graph, and interspecific and intraspecific competition. | 10 |
| Conservation and preservation | What separates conservation from preservation, and the economic, social, cultural and ethical arguments made for protecting an ecosystem. | 9 |
| Sustainable timber production and fishing | Coppicing, selective cutting, replanting and rotational felling, and the quotas, mesh sizes, closed seasons and exclusion zones used in fishing. | 8 |
| Human impacts and how they are controlled | Habitat destruction, pollution, overexploitation and invasive species, and the legislation, protected areas, habitat restoration and captive breeding that respond. | 9 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby sections
OCR A-Level Biology A Active Recall Guide
Every section, not just this one. 1,833 questions with their answers.