Punnett Squares: Predicting Traits

What You'll Learn

Punnett squares are tools for predicting the probability of offspring inheriting particular traits. They show all possible combinations of alleles from two parents.

Key Words

species
variation

Materials Needed

slides
onion skin
iodine stain
paper
colored pencils
coins (for Punnett squares)

Safety First

Adult supervision recommended.
Do not taste any materials.

Steps

Step 1 — Read

Look at the vocabulary words and write a definition for each in your own words.

Step 2 — Do

Survey your class for a genetic trait (attached vs. free earlobes, tongue rolling, hitchhiker's thumb). Create a bar graph of the results.

Step 3 — Observe

Draw a detailed diagram of what you observe.

Step 4 — Record

Write a conclusion: what did your results show? Did they match your prediction?

Check Your Understanding

Question 1

1 of 3

What is a Punnett square used for?