Lesson 3

How Hairy is a Population of Radish Plants?

Big Idea: Variation in traits can be measured. A graph gives us a picture that describes the trait variation collectively within a population.

Activity: Students investigate the hairiness trait in radish plants. They count hairs on plants and represent their data on a class graph. They find that variation in a population can be described by identifying the “mode” (the tallest stack of data values) and the “range” ( the lowest and the highest value). They speculate about what future generations of radish plants will look like if the environment stays the same or changes, for example, if hungry caterpillars arrive.

Materials to Have Ready

  • 50 sticky notes

  • 25 hand lenses

  • 25 small rulers

  • Radishes planted 4 weeks before the lesson

    • 8 pots

    • 48 radish seeds

    • 8 cups of potting soil

    • 1 lamp

    • 1 hydroponic lightbulb

    • 1 shallow container

Video Overview (2:08)

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