Evolution, Evidence & Life History — Investigation · Life Science & Scientific Inquiry, Grade 7
Five focused units, a three-session investigation, chapter review, and chapter quiz.
Explain inherited frequency change
Investigate
How can we test a selection explanation against other possibilities?
Materials
- Supplied population records and inheritance assumptions
- Notebook and paper for a branching or selection model
Before you begin
Use fictional organisms and paper models. Do not expose living organisms to predation or disease, and do not collect private family data.
Plan a fair test
The fictional color variant is stipulated heritable, and greater surviving-offspring contribution is reported for it under the stated ground conditions. Counts use the same stage and method; movement is not measured.
Method
- Calculate the variant percentage at each generation.
- Explain the connection among inheritance, conditions, and reproductive contribution.
- Distinguish an individual developmental change from population evolution.
- Consider movement or sampling as additional contributors.
- Write and revise a qualified explanation with an additional evidence test.
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.
| Generation | Dark variant | Total count |
|---|---|---|
| 1 | 20 | 100 |
| 2 | 35 | 100 |
| 3 | 50 | 100 |
Analyze and explain
- What is the overall percentage-point change?
- What supplied information strengthens selection beyond frequency alone?
- Which extra observations would address movement or sampling?
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
Frequencies are 20%,35%,50%, with a 30-percentage-point overall increase. The supplied inheritance and greater reproductive-contribution information support a selection mechanism under the stated conditions. Counts alone would be weaker evidence. Movement, sampling, and other changes need further records. No individual decided to acquire the variant, and the pattern does not predict a universal future rate or rank organisms by worth.
Compare this model with the learner’s actual evidence. Different measurements can support a different conclusion; check the reasoning and limitations, not matching wording.