Car board game.

CareerStart lessons: Grade six

LEARN NC was a program of the University of North Carolina at Chapel Hill School of Education from 1997 – 2013. It provided lesson plans, professional development, and innovative web resources to support teachers, build community, and improve K-12 education in North Carolina. Learn NC is no longer supported by the School of Education – this is a historical archive of their website.

Learning outcomes

  • Students will use theoretical probability via tree diagrams and/or Punnett squares to predict the outcome of the potential of male/female offspring and the crossing of two genes.
  • Students will gain an understanding of the importance of math to careers in biology.

Teacher planning

Materials needed

Time required for lesson

One class period


  1. Review theoretical probability with the class.
  2. Share with students some basic background information about careers in biology:

    A biologist is a scientist devoted to and producing results in biology through the study of organisms. Typically biologists study organisms and their relationship to their environment. Biologists involved in basic research attempt to discover underlying mechanisms that govern how organisms work. Biologists involved in applied research attempt to develop or improve medical, industrial or agricultural processes. Some biologists work in management positions coordinating or supervising research. Technicians perform specialized tasks using laboratory equipment.

    There are many types of biologists. Some deal with the macroscopic world and other with the microscopic. There is much overlap between different fields, and it is often hard to classify a biologist as only one of them. Some of the fields are:

    • Animal
    • Biochemistry
    • Cell
    • Developmental
    • Ecology
    • Evolutionary
    • Genetic
    • Microbiology
    • Molecular

    Many jobs in biology as a field require an academic degree. A PhD (or equivalent) is generally required to direct independent research but a bachelor’s or master’s degree is sufficient for most non-research positions. Training on the undergraduate level usually is very general while later training involves a specialization in a specific area of biology.

    (Source: U.S. Department of Labor’s Occupational Outlook Handbook.)

  3. Explain to the students that some biologists work to understand genetics. Studying genetics can be beneficial because it helps predict the likelihood (probability) of certain traits occurring, whether it is with plants, animals, or humans. A British geneticist named Reginald Punnett created his own way to determine the probability of traits occurring by making a table that looks like a tic-tac-toe board. Today, we call the table a Punnett square. To create a Punnett square, the parents’ genotypes are listed horizontally and vertically along the borders of the square. When traits from each parent are crossed, the results are the probability of the offspring’s genotype.
  4. Guided practice: Walk students through example problems on “Let’s Review” handout.
  5. Independent practice: Have students complete handouts — “Biology Rules!” (for regular students) OR “I Could be a Biologist!” (for advanced students).


Optional resources for more information on the topics covered in this lesson

Dog Breeding
This PBS game challenges students to breed a certain type of puppy by selecting parents with the right traits.
The Story of Mendel
This website gives a brief biography of Mendel, explains his experiments in genetics, and allows students to breed their own hybrid pea plants in an interactive experiment.
Mutant Fruit Flies
Exploratorium explains how gene mutations occur using the example of fruit flies.
DNA from the Beginning
This comprehensive website by the DNA Learning Center covers 75 experiments that led to modern genetics. For each experiment, there is a written explanation of the concept, an animation to further explain, a gallery of related images, a video with an expert explaining the concept, a biography of the experimenting scientists involved in the discovery, and an interactive problem so that students can test their knowledge.

North Carolina curriculum alignment

Mathematics (2004)

Grade 6

  • Goal 4: Data Analysis and Probability - The learner will understand and determine probabilities.
    • Objective 4.04: Determine and compare experimental and theoretical probabilities for simple and compound events.

  • Common Core State Standards
    • Mathematics (2010)
      • Grade 7

        • Statistics & Probability
          • 7.SP.8Find probabilities of compound events using organized lists, tables, tree diagrams, and simulation. Understand that, just as with simple events, the probability of a compound event is the fraction of outcomes in the sample space for which the compound...

    • North Carolina Essential Standards
      • Science (2010)
        • 7.L.2 Understand the relationship of the mechanisms of cellular reproduction, patterns of inheritance and external factors to potential variation among offspring. 7.L.2.1 Explain why offspring that result from sexual reproduction (fertilization and meiosis)...