Traits and Heredity

This unit introduces students to the basic laws of heredity and the origins of classical genetics. Students will learn about Gregor Mendel’s experiments with patterns of inheritance and practice using the principles of heredity to determine traits.

Students will also learn about genetic diseases and consider the problem of whether or not potential parents should find out if they are carriers of these diseases.

Activities

Scene: How Now Brown Bunnies?

In this scene, several students struggle to understand how their two black rabbits produced six black baby rabbits as expected, but also two brown ones!

Duration: Approximately 50 minutes

Lab: Punnett Square and Probability

Noticing that the genetic information is not always immediately apparent, students connect data they collected by way of a probability experiment to the format of the Punnett Square.

Duration: Approximately 50 minutes

Lesson: Meet Mendel the Monk

This lesson is a brief introduction to the famous work done by Gregor Mendel related how genetics works. It is intended to be a light-hearted way to introduce Mendel.

Duration: Approximately 30 minutes

Reading: Mendel's Experiments

Entirely focused on a corresponding 8-page document, this section of the unit examines that work of Mendel and his pea plants with meticulous detail and illustration.

Duration: Approximately 180 minutes

Conversation: Pros and Cons of Genetic Testing

This activity is an opportunity for students to apply their introductory knowledge of genetics to a difficult real-life policy question. Ultimately they take a position and argue for it.

Duration: Approximately 90 minutes

Reading: Athletics and Sickle Cell Trait

This brief article will ideally lead to a policy discussion about the NCAA’s rule about testing for sickle cell trait.

Duration: Approximately 30 minutes

Teacher Tune-ups

• What is a Punnett Square and how does it relate to dominant and recessive traits?
• What are the big ideas related to Mendel’s experiments?
• Beyond Mendel’s Laws: What else do we know about genetics, beyond Mendel?

Student View of Visuals and Activities

Some teachers prefer to have students view the slides and other visual assets in this unit directly instead of projecting them in class. Below is a web page to share with students with links to some of same items that are within in the teacher lesson plans, but without the explanatory text for the teacher.

 

• Student Links to Unit L3 Slides and Other Visuals

Original SciGen Unit

This unit has been adapted from "7.5 Traits and Heredity" in the Word Generation program led by Catherine Snow (Harvard University) through a SERP collaboration with the Boston Public Schools and other districts in Massachusetts and Maryland.

PDFs of that earlier unit's teacher and student editions are available at the Science Generation Download Center.

trait

noun – an observable characteristic based on genetic background

What are some traits of a pea plant?

dominant

adjective – always observable, even when paired with a different trait

What is a dominant trait for the stem of a pea plant?

recessive

adjective – only visible when no dominant trait is present

What is the recessive trait for the flower color of a pea plant?

inherit

verb – to receive a trait from a parent or previous generation

What happens when an offspring inherits one dominant and one recessive trait from its parents?

offspring

noun – a person’s children or an animal’s young

Describe the offspring of the black rabbits, Jet and Midnight.

generation

noun – a single step of the ancestry of a living thing (i.e., a mother and daughter are one generation apart)

Explain how a recessive trait can skip a generation.

skeptical

adjective – questioning common beliefs

What theories of heredity made Mendel skeptical?

hybrid

noun – an offspring of two different varieties of plant or animal

Describe how pea plants produce a generation of hybrids.