A black Labrador standing beside a wicker basket of four puppies: two black, one yellow and one chocolate brown, all with the same floppy ears.

Why don't puppies from the same litter look the same?

Like Parent, Like Baby? Traits and Families

The mission

The farm dog had seven puppies. Both parents were black, so everyone expected seven black puppies. But when Lena looked in the basket, she counted four black puppies, two yellow ones and one brown one. "Are they really from the same parents?" she asked. They all had the same floppy ears and thick tails. So why don't puppies from the same litter look the same?

Your team's job

Your team's job: read the family files, count the evidence, and explain what the young share and what makes each one different.

A simple figure of Gregor Mendel in a dark monk's robe standing between two staked pea plants, holding out an open pea pod with three yellow peas and one green pea.

In the real world

Meet Gregor Mendel

Gregor Mendel was a monk and teacher at St Thomas's Abbey in Brno, in what is now the Czech Republic. From 1856 to 1863 he grew thousands of pea plants in the abbey garden and counted their traits: tall or short stems, yellow or green peas, round or wrinkled peas. He found that traits could skip a generation and come back, and that the counts followed a pattern, about 3 to 1. He published his work in 1866, but almost nobody noticed until 1900, sixteen years after his death. Today he is called the father of genetics.

Materials

No materials needed: just the printed sheets.

Safety

When the class lines up as a bar graph, walk to your line and leave space so no one is pushed into furniture.
Peas are pictures only; nothing is eaten.

See the whole lesson as slides

Predict, Hunt, Reveal and Act, with your teacher notes on the N panel. Included with your plan, or use one of your free lessons.

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