Biodiversity Change Caused by Genetic Techniques

Q1 — Sample Band 6 response (8 marks), annotated

Biodiversity is the variety of life measured at three levels: genetic diversity (allele variation within populations), species diversity (the range of species in a habitat) and ecosystem diversity (the variety of communities and ecological interactions). [1 — definition + three levels]

At the genetic level, the data show a clear reduction: the number of canola cultivars planted has fallen from 12 to 2, and one cultivar now occupies about 78% of the sown area. This is the lesson's "uniformity" pattern — a few successful varieties dominate, so allele variation within the crop falls. [1 — genetic-level effect with data]

At the species level, farmland bird richness has dropped from 17 to 14 species and native solitary bee species richness has fallen 22%. The change is modest for birds but substantial for native solitary bees. The honeybee result reminds us that an abundance figure for one species does not capture species diversity. [1 — species-level effect with data]

At the ecosystem level, the change in pollinator species composition (native solitary bees down, honeybees flat) implies altered pollination interactions in the surrounding plant communities, which can ripple into other species over time. The lesson's Card 2 warns that uniformity in one crop "may also" make surrounding ecosystems less varied or more vulnerable, even when productivity rises. [1 — ecosystem-level effect with reasoning]

Yield rose by 56%, which is genuinely a productivity gain, but the lesson's Copy Notes explicitly say "improved productivity is not the same thing as improved biodiversity". Productivity measures food output per hectare; biodiversity measures variation at three different levels. In this region, productivity went up while two of the three biodiversity levels went down. [1 — explicit productivity ≠ biodiversity argument with the lesson's own line]

This is therefore a mixed rather than positive or negative outcome. Calling it "positive" because yield rose is the equivalent of the misconception in the Think First task. Calling it "negative" because two diversity levels fell ignores the legitimate species-level food-security benefit. [1 — rejects both absolute claims with explicit lesson reference]

The defensible judgement is that this GM technique may support short-term productivity and one species-level outcome (food yield), but reduces biodiversity at the genetic level within the crop and creates uncertain ecosystem-level changes. Whether the overall biodiversity verdict is acceptable depends on whether genetic and ecosystem-level diversity continue to fall over the next decade, or whether management (rotating cultivars, restoring hedgerows, monitoring pollinators) stabilises them. [1 — balanced, conditional judgement]

So the lesson's three-level framework, applied to this data, shows that this GM canola adoption has a positive productivity effect, a negative genetic-level biodiversity effect, and a mixed-to-negative species- and ecosystem-level biodiversity effect — exactly the kind of "positive at one level, negative at another" verdict that the lesson treats as the strongest HSC response. [1 — overall synthesis in lesson terminology]

Marking criteria.

• 1 mark — Defines biodiversity and names the three levels (genetic, species, ecosystem).
• 1 mark — Uses the data to describe the genetic-level effect (cultivars 12 → 2, one cultivar dominates).
• 1 mark — Uses the data to describe the species-level effect (bird and/or solitary bee species fall).
• 1 mark — Uses the data to describe the ecosystem-level effect (changed pollinator community / altered interactions).
• 1 mark — Explicitly distinguishes productivity (+56% yield) from biodiversity and rejects equating the two.
• 1 mark — Rejects both "biotechnology always increases" and "biotechnology always decreases" biodiversity using the lesson's framing.
• 1 mark — Reaches a balanced "positive at one level, negative at another" verdict conditional on management.
• 1 mark — Uses lesson-specific terminology throughout (genetic / species / ecosystem diversity, uniformity, monoculture, mixed effects, productivity ≠ biodiversity).

Q2 — Sample Band 6 response (8 marks), annotated

Conservation genetics is the use of genetic information and technologies (e.g. DNA fingerprinting, marker-assisted breeding, SCNT) to manage and conserve populations. It operates primarily at the genetic level of biodiversity by identifying allele variation within a population, then guiding management to maintain or restore that variation. Because species persistence depends on genetic variation, this genetic-level action also has direct consequences at the species level. [1 — definition + genetic level link]

Strategy A — Insurance population. A captive insurance population managed with DNA fingerprinting to maximise MHC variation directly protects genetic-level biodiversity: rare alleles are preserved in a controlled setting even while wild populations collapse. [1 — A: genetic-level effect named] Its main limitation is that it does not by itself restore wild populations — without release, species-level continuity in the wild still depends on the wild population coping with DFTD. [1 — A: limitation named]

Strategy B — Genetic-rescue SCNT cloning. SCNT cloning from tissue of devils that died before DFTD spread can reintroduce MHC alleles now lost from the wild population, raising allele variation in the wild gene pool. The benefit is therefore genetic-level (more MHC variation), translating into a species-level benefit (better chance of resisting DFTD and persisting as a species). [1 — B: genetic and species-level effect named] Limitations include the small number of individuals likely to be cloned (a narrow founder genetic contribution), high cost, and the need for continuing human management. [1 — B: limitation named]

Strategy C — Do nothing genetic. Habitat protection and DFTD-free quarantine zones operate at the ecosystem level and protect species persistence in those zones, but they do nothing to address the underlying genetic-level problem of MHC variation loss. So under continued DFTD pressure, even protected wild populations remain genetically vulnerable. [1 — C: level identified + key limitation]

The lesson explicitly rejects both "biotechnology always saves species" and "biotechnology always disrupts nature". Each of A, B and C is positive at one biodiversity level and limited at another — A protects genetic variation but not the wild ecosystem, B restores genetic variation but at high cost and with small founder numbers, C protects habitat but not allele variation. A balanced "may help / may not be enough on its own" framing reflects this multi-level reality and prevents the single-level oversimplifications the lesson warns against. [1 — balanced multi-level framing applied across all three strategies]

The strongest recommendation is therefore a combination: maintain A (insurance + DNA-managed breeding) to protect genetic-level variation in captivity, deploy B (SCNT-based genetic rescue) selectively to restore lost MHC alleles in the wild, and continue C (habitat and quarantine) so that the wild population released into is ecologically supported. This combined recommendation supports continuity of the Tasmanian devil species at all three biodiversity levels and is the kind of mixed, conditional verdict the lesson treats as the strongest evaluation. [1 — justified recommendation, integrated and using precise lesson terminology]

Marking criteria.

• 1 mark — Defines conservation genetics and links it to the genetic level of biodiversity.
• 1 mark — Identifies a biodiversity-level effect of Strategy A (insurance population protects within-species genetic variation).
• 1 mark — Identifies a clear limitation of Strategy A (does not by itself restore the wild population / species level).
• 1 mark — Identifies a biodiversity-level effect of Strategy B (SCNT restores lost MHC alleles → genetic + species level).
• 1 mark — Identifies a clear limitation of Strategy B (narrow founder genetics / cost / requires ongoing management).
• 1 mark — Identifies a biodiversity-level effect and limitation of Strategy C (ecosystem protection but no allele restoration).
• 1 mark — Explicitly applies the lesson's balanced "may help / may not be enough" framing rather than ranking one strategy as universally best.
• 1 mark — Reaches a justified integrated recommendation using precise lesson terminology (genetic / species / ecosystem diversity, conservation genetics, threatened population, mixed outcomes).