Biology • Year 12 • Module 6 • Lesson 11
Biodiversity Change Caused by Genetic Techniques
Lock in the vocabulary of biodiversity at three levels, the negative/positive/mixed framing of biotechnology, and the difference between productivity and biodiversity.
1. Term–definition match
The ten definitions below are shuffled. In the right-hand column write the matching term from this list: biodiversity, genetic diversity, species diversity, ecosystem diversity, monoculture, conservation genetics, allele, clone, biotechnology, resilience. 10 marks
| # | Definition (shuffled) | Matching term |
|---|---|---|
| 1.1 | The variety of life measured across genetic, species and ecosystem levels. | |
| 1.2 | Variation in alleles within a population or species. | |
| 1.3 | The variety of species present in a habitat or ecosystem. | |
| 1.4 | The variety of ecosystems, communities and ecological interactions. | |
| 1.5 | Large-scale growth of genetically similar or identical crop plants. | |
| 1.6 | The use of genetic information or technologies to help manage and conserve populations. | |
| 1.7 | One version of a gene at a particular locus; the unit of variation within a population. | |
| 1.8 | An offspring genetically near-identical to its parent (produced asexually or by lab techniques such as somatic cell nuclear transfer). | |
| 1.9 | The use of living organisms, cells or molecular techniques to make products or modify traits. | |
| 1.10 | The ability of a population or ecosystem to absorb disturbance and continue functioning. |
2. Classify each effect by biodiversity level
For each scenario below, identify whether the biodiversity effect is mainly at the genetic, species or ecosystem level. Write your answer in the column on the right. 8 marks
| # | Scenario | Level (genetic / species / ecosystem) |
|---|---|---|
| 2.1 | A wheat crop in a region relies almost entirely on one elite genotype. | |
| 2.2 | Conservation genetics is used to prevent the extinction of a threatened mountain pygmy possum population. | |
| 2.3 | A change in agricultural practice alters the range of pollinators and soil microbes in surrounding hedgerows. | |
| 2.4 | DNA screening identifies which captive cheetah individuals carry rare alleles, so they are prioritised for breeding. | |
| 2.5 | A genetically modified cotton crop reduces pest pressure, which in turn changes the abundance of predator insects across the paddock. | |
| 2.6 | A single highly successful banana cultivar (Cavendish) is grown clonally worldwide. | |
| 2.7 | Reintroducing a captive-bred Tasmanian devil into the wild stops a regional population from disappearing. | |
| 2.8 | A river catchment loses three native fish species after long-term land-use change. |
3. True or false — with correction
For each statement, circle T or F. If the statement is false, write the corrected version. 10 marks (1 for T/F, 1 for the correction where needed)
3.1 Biodiversity refers only to the number of different species in an area. T / F
3.2 A genetic technique that increases crop productivity automatically increases biodiversity. T / F
3.3 Conservation genetics can identify low-diversity populations and guide management to reduce inbreeding. T / F
3.4 Reduced genetic variation always makes a population more resilient to environmental change. T / F
3.5 A biotechnology can have a positive effect at one biodiversity level and a negative effect at another. T / F
4. Cloze — fill the blanks
Use each term from the word bank exactly once. Word bank: genetic · species · ecosystem · uniformity · monoculture · conservation genetics · inbreeding · productivity · mixed · resilience. 10 marks
Genetic techniques can affect biodiversity at three levels: (4.1) ____________ diversity (the alleles within a population), (4.2) ____________ diversity (the number and abundance of species), and (4.3) ____________ diversity (the variety of communities and interactions). When a single elite genotype is used at scale, the resulting (4.4) ____________ can lower diversity, especially under (4.5) ____________ cropping. Although short-term (4.6) ____________ may rise, lower genetic variation can reduce (4.7) ____________ to disease or environmental change. By contrast, (4.8) ____________ uses DNA data to identify low-diversity populations and to reduce (4.9) ____________ in small populations. The honest conclusion is that biotechnology often has (4.10) ____________ biodiversity effects — positive at one level, negative or uncertain at another.
5. Function recall
Answer each in 1–2 sentences using precise terms from the lesson. 8 marks (2 each)
5.1 What is the function of measuring biodiversity at three levels (genetic, species, ecosystem) rather than just one?
5.2 What is the function of conservation genetics for a small, isolated threatened population?
5.3 What is the function of genetic variation in a crop population facing a new pathogen?
5.4 What is the function of using balanced "may/depends on" language when evaluating biotechnology and biodiversity?
6. Build a concept map
Draw labelled arrows between the six terms below to show how genetic techniques can push biodiversity in different directions. Each arrow must carry a linking phrase (e.g. "reduces", "supports", "may threaten"). Aim for at least 6 labelled arrows. 6 marks
Supplied terms: genetic technique · monoculture · genetic diversity · resilience · conservation genetics · threatened population.
Q1 — Term–definition matches
1.1 biodiversity • 1.2 genetic diversity • 1.3 species diversity • 1.4 ecosystem diversity • 1.5 monoculture • 1.6 conservation genetics • 1.7 allele • 1.8 clone • 1.9 biotechnology • 1.10 resilience.
Marking notes. 1 mark per correct term. No half-marks.
Q2 — Classify each effect by biodiversity level
2.1 genetic (a crop dominated by one genotype reduces allele variation within the species). 2.2 species (preventing extinction is a species-level outcome). 2.3 ecosystem (changes to pollinators and soil microbes are community-level / interaction-level effects). 2.4 genetic (prioritising rare alleles maintains allele variation). 2.5 ecosystem (changing pest/predator abundance is a community-interactions effect). 2.6 genetic (a single clonal cultivar lowers within-species allele variation). 2.7 species (reintroduction protects species persistence in that region). 2.8 species (loss of three species is a species-diversity outcome).
Marking notes. 1 mark per correct classification. Accept "ecosystem" for 2.5 even if students add a species-level note about predator abundance.
Q3 — True / false with correction
3.1 False. Correction: biodiversity has three levels — genetic, species and ecosystem — not just species count.
3.2 False. Correction: improved productivity is not the same thing as improved biodiversity; productivity may go up while genetic, species or ecosystem diversity is reduced.
3.3 True.
3.4 False. Correction: reduced genetic variation usually lowers resilience, because fewer individuals are likely to carry alleles suited to a new pressure (e.g. a new pathogen).
3.5 True.
Marking notes. 1 mark for the correct T/F; 1 mark for a biologically accurate correction (no mark for "no, that's wrong" without a stated fix).
Q4 — Cloze paragraph
4.1 genetic, 4.2 species, 4.3 ecosystem, 4.4 uniformity, 4.5 monoculture, 4.6 productivity, 4.7 resilience, 4.8 conservation genetics, 4.9 inbreeding, 4.10 mixed.
Marking notes. 1 mark per blank. Spelling must be recognisable.
Q5.1 — Function of three-level analysis (2 marks)
Measuring biodiversity at genetic, species and ecosystem levels prevents superficial answers, because a single technique can improve diversity at one level while reducing it at another (e.g. a crop technique can raise species-level food security while reducing genetic diversity within the crop) [1]. Three-level analysis is therefore what allows an honest, mixed judgement rather than a yes/no claim [1].
Q5.2 — Function of conservation genetics (2 marks)
Conservation genetics uses DNA information to identify low-diversity or inbred populations and to guide breeding decisions that maintain rare alleles [1]. For a small isolated threatened population, this can reduce inbreeding, protect genetic variation and improve the chance of long-term survival [1].
Q5.3 — Function of genetic variation in a crop facing a new pathogen (2 marks)
Genetic variation means individual plants carry different allele combinations, so some plants are more likely to carry alleles conferring partial or full resistance to the new pathogen [1]. This raises the chance that at least part of the population survives and reproduces, so the crop as a whole is more resilient [1].
Q5.4 — Function of balanced "may / depends on" language (2 marks)
Balanced language ("may increase / may reduce / depending on the level") reflects the actual biology: biotechnology effects are positive, negative or mixed depending on context and the biodiversity level considered [1]. It avoids the slogans "biotechnology always helps" and "biotechnology always harms", which are both rejected by the lesson [1].
Q6 — Sample concept map (6 marks)
A correct map should include arrows such as:
- genetic technique — can promote → monoculture
- monoculture — reduces → genetic diversity
- genetic diversity — supports → resilience
- monoculture — therefore lowers → resilience
- genetic technique — also enables → conservation genetics
- conservation genetics — helps protect → threatened population
- conservation genetics — maintains → genetic diversity
Any biologically valid linking phrases are accepted. Award 1 mark per correctly labelled arrow, up to 6. Award full marks for a map that shows the technique branching into a "reduces diversity" pathway and a "supports diversity" pathway.