Key term
OCR A-Level Biology H420
Cell Structure
Biological Molecules
Nucleotides and Nucleic Acids
Enzymes
Biological Membranes
Cell Division, Cell Diversity and Cellular Organisation
Exchange Surfaces
Transport in Animals
Transport in Plants
Communicable Diseases, Disease Prevention and the Immune System
Biodiversity
Classification and Evolution
Communication and Homeostasis
Excretion as an Example of Homeostatic Control
Neuronal Communication
Hormonal Communication
Plant and Animal Responses
Topic overviewTropisms and plant responses to stress and herbivoryPlant hormones and their commercial usesThe nervous system and the brainReflex actions and the knee jerk reflexFight or flight and the control of heart rateThe structure of skeletal muscleThe neuromuscular junction and the sliding filament model
Photosynthesis
Respiration
Cellular Control
Patterns of Inheritance
Manipulating Genomes
Cloning and Biotechnology
Topic overviewNatural plant cloning and taking cuttingsMicropropagationAdvantages and disadvantages of plant cloningAnimal cloning: embryo twinning and nuclear transferAdvantages and disadvantages of animal cloningMicroorganisms in food productionAseptic techniqueFermentation and its conditionsThe microbial growth curveImmobilised enzymes
Ecosystems
Populations and Sustainability
Practical Skills and Mathematical Requirements
Biodiversity
- 6 subtopics
- 11 things to know
- Components 02 and 03
What Biodiversity covers
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.
Where it is assessed
Components 02 and 03
Module 4 is examined on Biological Diversity, then the unified paper.
Check the OCR specification ↗The 6 subtopics
Each one has its own page.
- The three levels of biodiversityHabitat, species and genetic biodiversity, the species richness and evenness that together make up species biodiversity, and examples of each.Open →
- Sampling methods and equipmentRandom, opportunistic, stratified and systematic sampling and when each is appropriate, and quadrats, sweep nets, pitfall traps and pooters.Open →
- Simpson's Index of DiversityWhat the index takes into account, the formula and each step of the calculation, and what values close to one and close to zero indicate.Open →
- Measuring genetic biodiversityThe proportion of polymorphic gene loci and its calculation, and why captive breeding populations, rare breeds and pedigree animals are used.Open →
- Threats to biodiversity and reasons to maintain itPopulation growth, monoculture and climate change, and the ecological, economic and aesthetic arguments for maintaining biodiversity, including keystone species.Open →
- Conservation: in situ and ex situProtected areas, seed banks, botanic gardens and zoos, and the roles of CITES, the Rio Convention and the Countryside Stewardship Scheme.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Numbers
How is Simpson's Index of Diversity interpreted?
Key term
Compare in situ and ex situ conservation.
Evaluation
Why is opportunistic sampling limited?
Key term
What are quadrats and what organisms are they particularly suited for sampling?
Key term
What is systematic sampling?
Key term
What is the first step when calculating Simpson's Index of Diversity?
Key term
What is in situ conservation?
Key term
What is ex situ conservation?
Key term
What is a keystone species?
Process
How is genetic biodiversity measured, and which populations have documented genetic records?
Take Biodiversity further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Species richness vs Species evenness
Species richness: number of different species present in a habitat. Species evenness: relative abundance of individuals across the species present.
Questions from this topic
Each one with the model answer underneath.
- 1
What does the term biodiversity refer to?
Model answer
The range and intricacy of living things
- 2
Why is biodiversity considered an important indicator when studying habitats?
Model answer
It provides a measure of the health and stability of ecosystems, allowing comparison between habitats and detection of environmental changes
- 3
What is habitat biodiversity?
Model answer
The variety of different habitats within an area or ecosystem.
- 4
Define species biodiversity.
Model answer
The variety of different species present in an area or community.
- 5
What is meant by genetic biodiversity?
Model answer
The variety of genes or alleles within a species or population.
- 6
Name the three levels at which biodiversity can be considered.
Model answer
Habitat biodiversity, species biodiversity, and genetic biodiversity.
What is inside Levo
Six ways to work the same material.
Biodiversity revision questions
- What does Biodiversity cover in OCR A-Level Biology?
- 6 subtopics: the three levels of biodiversity, sampling methods and equipment, simpson's index of diversity, measuring genetic biodiversity, threats to biodiversity and reasons to maintain it and conservation: in situ and ex situ. Each one has its own page with questions and model answers.
- How is Biodiversity organised?
- By the OCR H420 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Biodiversity, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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