Genetic Traits

Lesson Plan

State Standards:

3.4 Genetic traits result in observed inheritance patterns.
3.6 Probabilities for genotype and phenotype combinations in monohybrid crosses can be modeled using a Punnett Square.

Essential Question:

How do your genes express themselves that make you look similar or different from other people?

Lesson Question:

What is the probability of parents passing along these traits to their offspring? Can we know about a parent's genotype if we know the offspring's genotype?


During long block of eighty-one minutes and one fifty-minute block, students will explore variations and probability of human appearances with respect to specific, pre-selected traits (including hitchhikers' thumb; widow's peak; attached ear lobes; tongue rolling; and hypermobility). They will be able to identify the percent of students in the population with the trait and identify the probability of offspring having the trait depending on the genes of the parents, as well as traits resulting in their own uniqueness.


Students will learn about their own uniqueness due to variations of specific human traits by observation of themselves, playing the card game below, and applying previously acquired understanding of Punnet squares.

Lesson Experiences:

Day 1

Lesson Experiences:
Elicit - What makes your appearance different from other anyone else? Elicit responses.

Engage – Using, show students appearances of traits. Survey (copy below resources) your own specific traits.

Explore – Students will identify inherited traits of humans they share and do not share with others, resulting in their recognizing their own uniqueness.

Activity Type:
View Images/Objects
Students examine both still and moving (e.g., video, animations) images/objects; print-based or digital format
Web sites
Identify purpose of lesson.
(Cards would be either prepared by class the day before or pre-made for them.)

Identify pairs of contrasting traits found on each deck of cards.

Follow directions on website below for card game about traits:
Once the group is familiar with all of the inherited traits described, try this second activity!
Shuffle the game cards, then draw a card from the top of the deck. Invite your group to stand up and form a circle. Show everyone the picture of the trait.

Everyone who has this trait should stay standing. Those who do not have the trait should sit down. Once a person sits down, they should not get up again. Continue with each game card until only one person is left standing.

How many cards did it take to find one person with a unique combination of traits?

Shuffle the cards and play again as many times as you would like.
Online Component: Traits Trivia
Classroom Materials: Cards; teacher-made chart for students to use to identify number of students with each trait and whether the trait is dominant or recessive.

Explain – Provide information to students about the dominant and recessive allele for each trait. Students complete next three columns of survey started during “Engage”. Review how to find probability of outcomes.
Evaluate – Create Punnet square problems using information from survey. Students are graded on accuracy of use of information from survey, finding genotypes, phenotypes, and probability.

Day 2: Lesson Experiences:
Elicit - If an offspring has a trait or if the offspring does not have the trait, what do we know about his/her alleles? What do we know about his/her parents' alleles?
Explore – Using two pictures showing contrasting alleles, each group identifies alleles for each offspring.
Explain – Explain to students how to apply information about genotype of offspring in a Punnet square to determine parents' genotype and phenotype.
Elaborate - Students in each group will find probability of genotypes of offspring of parents with given genotypes for each trait on a teacher generated worksheet.
Extend – Using drawing software on a wiki, students create a person (copy of assignment below resources) identifying traits, applying Punnet squares, and probability. Complete this for homework. Evaluate using rubric below.
Additional Extension: Complete last two columns in survey.


Through an inquiry-based lesson, students will be able to identify variable human traits' probability and the variables that contribute to their unique combination of genes. They have applied Punnet squares to determine probability of offspring, and can demonstrate that some traits are more frequently expressed than others.


Genetics Create a Person Grading Rubric


Human Traits
Human Genetics Worksheet
Traits Trivia

Miller, Kenneth R, Ph.D., and Levine, Joseph, Ph.D. (2002).Biology.New Jersey: Prentice Hall.
cards; teacher-made chart for students to use to identify the number of students with each trait and whether the trait is dominant or recessive

Genetics Project-Design a Species

drawing software such as Google Sketchup

teacher-made materials ;

What Traits Do You Have That Make You Similar Or Different From Others?

Check each step as you work.Genetics Project: Design a Species