Breeder's Challenge

What you'll do

This is a breeding lab simulation. For each of five stages you'll get a brief explanation, build a Punnett square prediction, breed a batch of original fictional creatures called Florns, compare your prediction to the actual outcome, and explain what you observed.

Learning objectives

• Predict ratios Predict offspring genotypes and phenotype ratios from a cross (NGSS* HS-LS3-3).
• Probability Use probability to explain why actual offspring vary from the prediction (NGSS* HS-LS3-3).
• Determine genotype Determine an unknown genotype from observed traits and offspring (NGSS* HS-LS3-1).

Meet the Florn

Florns are a fictional diploid organism with two independently assorting Mendelian traits: horns (H, horned, is dominant over h, hornless) and body color (G, green, is dominant over g, purple). No real organism was used as a model; all genetics are original.

Five stages

1. A — One trait, small batch: Predict then breed 8 Florns. See how they scatter from 3:1.
2. B — Large batches converge: Keep breeding the same cross and watch the running tally approach 3:1.
3. C — Test cross: Uncover a hidden genotype using a strategic cross.
4. D — Dihybrid: Fill a 4×4 Punnett square and predict 9:3:3:1.
5. E — CER capstone: Build a Claim–Evidence–Reasoning response about why real breeding never lands exactly on prediction.

Start Stage A