Heritable or Acquired?

People often have intuitive ideas about whether a trait is inherited (through genes) or acquired (due to the environment)—but in practice, this distinction can be tricky to untangle! In this activity, students dig into the data to figure it out. They learn about a population of organisms with a trait that varies (8 tricky examples are provided). Then they analyze data about the organisms' offspring to decide whether the differences are inherited or acquired.

1. Remind students that traits are influenced by both genes and the environment by revisiting one or more of the following activities from the Traits module:
   1. Traits: Weigh the Evidence
   2. How Traits Are Made (video)
   3. Selected examples from Trait Shuffle
2. Distribute a pair of examples (e.g., tail length in dogs and cats) to each student or pair. The examples in the pdf are arranged from easiest to hardest. See answer key for more information about the examples.
3. (Optional) Discuss the meaning of acquired in this context: the trait difference is caused by environmental factors.
4. (Optional) Go through one example as a class, reviewing how to write a simple evidence statement.

• Placing this activity first in the module may encourage students to focus on traits rather than incorporating mutation and recombination in their explanations.

• An organism's traits are the product of both genetic and environmental factors.
• Only trait variations influenced by genes can be passed to offspring; trait variations due to the environment are not passed to offspring.

“Traits acquired during the life of an organism, such as large muscles, will be passed to offspring.”

Copies

Heritable or Acquired? (pdf) — Includes 8 examples.

Choose an example from Trait Shuffle and design an experiment to determine whether the trait is heritable or acquired.

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