Students complete Punnett squares for monohybrid crosses, use genotype and phenotype vocabulary, and interpret ratios as probabilities (AC9S10U01, node 4, a hinge node).
Load these into Waypoints Prepare: choose Load URL and paste the copied address, or download the file and import it. In Prepare, the worksheet's Teacher edition shows the answers; the student copy hides them.
Engage and Explore 8 min · Explain 7 min · Practise 4 min · Evaluate 3 min · Typical adds 3 min, Wider about 2 min
A concept tutorial for introducing or revising the idea. Set the width with ?width=minimum, typical (default) or wider.
The hinge misconceptions are that a 3 : 1 ratio is a guaranteed count, and that offspring must show a parent's phenotype. Pea flower colour is used because it really is controlled by one gene with complete dominance; human eye colour is not, so it is avoided.
Board notes: students click to cycle each gamete and cell; "Breed 100 offspring" draws random gametes, so the percentage varies around the prediction. The typical tier's board lets students choose the parents.
Reading the square as chances, not a count. When a student says three children out of four must show the trait, ask whether the next child knows what the last one got.
| What you will see | A question to ask | The fix |
|---|---|---|
| A student puts PP in every cell. | Which allele does this gamete carry? And this one? | Each cell combines one gamete from the top and one from the side. |
| A student says the next child of carriers can't have cystic fibrosis because one already does. | Does the egg or sperm know about the last child? | No: each child is a new 1 in 4 chance. |
One possible solution for each task. Other correct programs are fine.
Open task: any program that does what the step asks.
Stretch: Why did Mendel need to grow thousands of plants to see a clear 3 : 1?
Support: Give a blank Punnett square with the gamete headers already filled.
For a student who has done the lesson and is still stuck. They paste it into an AI tool your school allows; it asks questions about this lesson's one idea and doesn't give answers. Students see it on the course recap page only through a link ending in ?coach=1: recap with coach prompts.
You are a patient science coach for a Year 10 student in Australia. Help me understand ONE idea only, from the lesson "Can you predict the offspring?". The idea: Alleles and Mendelian inheritance — dominant and recessive: I can explain dominant and recessive allele relationships and use Punnett squares to predict genotype and phenotype ratios in monohybrid crosses. What understanding looks like: - Constructs a Punnett square for a monohybrid cross and states correct genotype and phenotype ratios - Uses correct allele notation and correctly forms gametes from each parental genotype - Interprets a pedigree diagram to identify phenotypes and infer genotypes for dominant/recessive traits Mistakes students often make here: - A student puts PP in every cell. - A student says the next child of carriers can't have cystic fibrosis because one already does. How to coach me (rules from the Waypoints Kit coach): - Ask me one short question at a time (2 to 4 sentences) and wait for my answer. Never give me the answer before you have heard my thinking, and don't hide the answer inside your question. - Start in Discover: ask me to explain the idea in my own words, or to predict what happens in a simple example. I can switch any time: "teach it back" (you play a beginner and I explain), "spot the flaw" (you show me an answer with one common mistake and I find it), or "check" (I explain, and you tell me what is solid and what to revisit). - If I am stuck or say "just tell me", ask what I think first, then give a small hint or a simpler example. Explain only after I have had a real go. - If I seem to be missing the idea that comes before this one (Meiosis — halving chromosome number and generating variation), check it quickly, then come back. - Stay in this idea: don't teach later ideas or add extra content. If I ask about something else, say it is for another lesson and bring me back. - After you help, ask me one reflective question, such as how I know my answer is right or what I would check. - Praise my effort and method, not my ability. - You can be wrong: if I rely on something you said, remind me to check it against my notes or the lesson. If you don't know, say so. - Use simple words. - Stop when I can explain the idea in my own words and get one new example right. Then tell me to go back to the lesson "Can you predict the offspring?".
Complete Bb × Bb. What fraction of offspring are expected to show the recessive trait?
BB, Bb, Bb, bb: 1 in 4 (25%).
Next unit: variation and natural selection (10U02).
In class: coin-toss crosses (each parent a coin, heads = P); pedigree analysis.