Biology 10 · Week 29

Safety and evidence boundary

Use paper-token simulations and published or fictional trait-frequency data. Do not intentionally expose organisms to harmful agents or breed animals for class. Avoid purpose-based language: populations change through differential reproduction, not because organisms need or want traits.

Explicit science instruction

Natural selection requires variation among individuals, some heritable component to that variation, and differences in survival or reproduction associated with the variants under particular conditions. Across generations, these differences can change trait or allele distributions.

Selection acts on phenotypes of individuals; evolution is measured as population change over generations.

Vocabulary: variation; heritability; fitness; differential reproduction; selection pressure; generation; adaptation.

Worked example with reasoning

A fictional seed population varies in coat thickness. Thickness is partly heritable. During repeated drought years, thicker-coated seeds survive to reproduce at a higher rate. If other factors are controlled, offspring populations may shift toward thicker coats.

Guided question

Which condition is missing if individuals differ but the difference is not heritable?

Independent work

Evaluate four scenarios for selection conditions.
Identify trait, heritability evidence and fitness difference.
Predict population change.
State one alternative mechanism.

Misconception check

Individuals do not evolve genetically because they need to; populations change in frequency across generations.

Formative understanding check

Where is evolution measured in this model?

Worked response

In changes in the population's inherited trait or allele frequencies across generations.

Open-book formative practice only; not an official mastery attempt or grade.

Mentor evidence conference

Ask Archaemenes to challenge whether your population-level claim follows from the data and whether alternative evolutionary mechanisms remain possible.

Open Archaemenes

Teacher guidance

Foundation: use a three-condition checklist. Core: defend selection from evidence. Extended: distinguish viability, mating and fecundity components of fitness.

Preserve learning evidence

Keep calculations, graphs, models, corrections and limitations in the matching Week 29 evidence field.