Biodiversity | OCR A-Level Biology A (H420)
Biodiversity
- 70 questions
- 6 subtopics
- Module 4: Biodiversity, evolution and disease
- Component 02 and Component 03
Biodiversity is the second section of Module 4.
It covers the three levels at which biodiversity is measured, the sampling methods used to estimate it, Simpson's Index of Diversity and the calculation behind it, what threatens biodiversity and why it is worth keeping, and conservation in situ and ex situ.
Sample questions from Biodiversity
Answer each one closed book first, then open the answer.
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The three levels of biodiversity
Name the three levels at which biodiversity can be considered.
Show the answer
Habitat biodiversity, species biodiversity, and genetic biodiversity. -
The three levels of biodiversity
What is species biodiversity?
Show the answer
The diversity of species in an area, encompassing both species richness and species evenness -
Sampling methods and equipment
Describe stratified sampling as a non-random method.
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The habitat is divided into distinct sub-groups (strata) based on a particular characteristic, and samples are taken from each stratum in proportion to its size or importance. -
Sampling methods and equipment
What are quadrats and what organisms are they particularly suited for sampling?
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Square frames used to sample organisms in a defined area, particularly for plants and slow-moving animals -
Simpson's Index of Diversity
After counting individuals of each species, what is the next step in calculating Simpson's Index?
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Count the total number of all individuals of all species -
Simpson's Index of Diversity
What is the first step when calculating Simpson's Index of Diversity?
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Count the number of individuals of each species -
Measuring genetic biodiversity
How can genetic diversity be expressed in terms of alleles?
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As the percentage of gene variants (alleles) in a genome -
Measuring genetic biodiversity
Why does a low proportion of polymorphic gene loci matter for a population?
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It indicates little genetic variation, so the population is less able to adapt to a change in its environment and is more vulnerable to disease.
The 6 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| The three levels of biodiversity | Habitat, species and genetic biodiversity, the species richness and evenness that together make up species biodiversity, and examples of each. | 15 |
| Sampling methods and equipment | Random, opportunistic, stratified and systematic sampling and when each is appropriate, and quadrats, sweep nets, pitfall traps and pooters. | 14 |
| Simpson's Index of Diversity | What the index takes into account, the formula and each step of the calculation, and what values close to one and close to zero indicate. | 12 |
| Measuring genetic biodiversity | The proportion of polymorphic gene loci and its calculation, and why captive breeding populations, rare breeds and pedigree animals are used. | 10 |
| Threats to biodiversity and reasons to maintain it | Population growth, monoculture and climate change, and the ecological, economic and aesthetic arguments for maintaining biodiversity, including keystone species. | 8 |
| Conservation: in situ and ex situ | Protected areas, seed banks, botanic gardens and zoos, and the roles of CITES, the Rio Convention and the Countryside Stewardship Scheme. | 11 |
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.