Ecological Evidence & Environmental Design — Extension · Life Science & Scientific Inquiry, Grade 7
Five focused units, a three-session investigation, chapter review, and chapter quiz.
Compare samples and evaluate a habitat plan
Investigate
What can equal-area observations support about an ecological proposal?
Materials
- Supplied plot and design records
- Notebook and a labeled sketch
Before you begin
The core requires only data. Optional observation from an accessible safe place must avoid disturbing organisms, trespass, suspect water, and unsuitable weather. No outdoor construction or purchase is required.
Plan a fair test
Compare plots of 1 m² with equal detection effort. Design A costs 80 tokens and reduces model runoff by 12 L; B costs 60 and reduces it by 10 L; budget is 100 tokens.
Method
- Calculate detected count per total sampled area for both habitats.
- Describe variation and distinguish density from species richness.
- Compare the two feasible designs using total reduction and reduction per token.
- State a criterion, a conditional recommendation, and a maintenance uncertainty.
- Propose a matched repeated test rather than treating a sample as an exact census.
Illustrative course data — use for analysis without equipment
Illustrative records: these are invented teaching data, not published measurements or the learner’s own observations. Actual measurements may differ; record them separately if you perform an optional suitable activity.
| Plot (each 1 m²) | Habitat A plant count | Habitat B plant count |
|---|---|---|
| 1 | 2 | 1 |
| 2 | 4 | 2 |
| 3 | 3 | 1 |
| 4 | 3 | 4 |
Analyze and explain
- What are the sampled densities?
- Does this one-species count measure whole biodiversity?
- Can different supported design priorities lead to different choices?
What a strong explanation includes
- Explain the relevant biological process accurately.
- Use the supplied evidence and show calculation steps with units where needed.
- Connect a labeled model or mechanism with the claim.
- State an assumption, evidence limitation, or useful next observation.
Parent / teacher guide: discuss after the investigation
A has 12/4=3 detected plants/m² and B 8/4=2. These selected counts do not measure all species richness or exact habitat totals. Design A provides greater total runoff reduction; B provides greater reduction per token, approximately 0.167 versus 0.15 L/token. Both fit the initial budget. A conditional choice should state priorities, missing maintenance information, sample limits, and a repeatable test.
Compare this model with the learner’s actual evidence. Different measurements can support a different conclusion; check the reasoning and limitations, not matching wording.
Extend the chapter investigation by evaluating its evidence and proposing a better test.
Problem 1
Answer and explanation
A has 12/4=3 detected plants/m² and B 8/4=2. These selected counts do not measure all species richness or exact habitat totals. Design A provides greater total runoff reduction; B provides greater reduction per token, approximately 0.167 versus 0.15 L/token. Both fit the initial budget. A conditional choice should state priorities, missing maintenance information, sample limits, and a repeatable test.
Problem 2
Answer and explanation
A has 12/4=3 detected plants/m² and B 8/4=2. These selected counts do not measure all species richness or exact habitat totals. Design A provides greater total runoff reduction; B provides greater reduction per token, approximately 0.167 versus 0.15 L/token. Both fit the initial budget. A conditional choice should state priorities, missing maintenance information, sample limits, and a repeatable test.
Problem 3
Answer and explanation
A has 12/4=3 detected plants/m² and B 8/4=2. These selected counts do not measure all species richness or exact habitat totals. Design A provides greater total runoff reduction; B provides greater reduction per token, approximately 0.167 versus 0.15 L/token. Both fit the initial budget. A conditional choice should state priorities, missing maintenance information, sample limits, and a repeatable test.