Ecology, Populations & Biodiversity — Investigation · Physics & Environmental Science, Grade 12
Use food webs, population models, habitat patterns, and representative sampling.
Biodiversity Sampling Plan
Investigate
Do equal-effort samples support a site comparison?
Use two dedicated sessions: first define the model, boundary, variables and comparison, then collect suitable records or analyze the complete supplied-data route; second complete calculations/graphs, compare alternatives, revise and prepare the report. Extend collection time where needed. Supplied-data work does not certify supervised laboratory minutes or mandated investigations.
Materials
- Notebook, graph paper, and calculator
- The supplied data table is sufficient for analysis
- Optional household setup described in the method; an adult checks safety
Before you begin
Use only the listed household materials or analyze the supplied data. An adult should review setup. No flames, strong acids/alkalis, unknown chemicals, household mains, radiation sources, or high-speed projectiles are needed. Keep food-study materials separate from eating and wash hands afterward.
Plan a fair test
Compare equal 1 m² quadrats with consistent organism categories and season. Use representative independent locations.
Method
- Write a prediction and the mechanism that supports it.
- Draw the setup or boundary; label axes, quantities, and units.
- Select quadrat locations without favoring dense or interesting patches.
- Count categories and calculate density and D=1−Σpi².
- Compare variation across quadrats and plan more sampling before a broad site claim.
- Record independent repetitions where possible, raw values, and instrument resolution.
- Write a claim citing numerical evidence, a limitation, and a follow-up test.
Example data — for analysis when materials are unavailable
Illustrative teaching data, not measurements from a real district laboratory. Analyze these when materials are unavailable and identify them as provided data. Do not claim to have performed a measurement you did not make.
| Site/quadrat | Species Acount | Species Bcount |
|---|---|---|
| A1 | 8 | 2 |
| A2 | 6 | 4 |
| B1 | 5 | 5 |
| B2 | 4 | 6 |
Analyze and explain
- Find diversity D for every quadrat.
- Do the supplied densities differ?
- What additional evidence would support a restoration claim?
- Link the pattern to a labeled particle, structure, energy or amount model from the chapter.
- Distinguish supplied illustrative records from measurements actually collected.
- Identify uncertainty and propose a comparison that would test an alternative explanation.
What a strong explanation includes
- A stated prediction, conditions, and controlled variables or explicit model boundary.
- A labeled table/graph with units, calculations, and attention to repeated values or uncertainty.
- A claim citing numerical evidence and a scientifically accurate mechanism.
- A limitation, alternative explanation, and useful follow-up test.
- Preserve initial reasoning and an evidence-supported revision.
- Check units, object/material identity, system boundary and physical assumptions.
Parent / teacher guide: discuss after the investigation
The diversity values are 0.32, 0.48, 0.50, and 0.48; density is 10 individuals/m² in each. These few samples suggest different evenness, not a complete habitat ranking. Comparable before/after and comparison-site data plus wider replication would improve inference. Preserve the original observations, intermediate working and a labeled mechanism. Report the relevant boundary and model assumptions, discuss an alternative explanation, and identify the next useful measurement; do not replace unexpected data with the illustrative record.
Compare this model with the learner’s actual evidence. Different measurements can support a different conclusion; check the reasoning and limitations, not matching wording.