Heredity - An Inventory of Traits

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Objective

Students will take inventory of their own easily observable genetic traits

Big Idea

Traits are observable characteristics that are passed down from parent to child.

NGSS

1 minutes

This lesson is part of a unit that addresses the following Life Science Disciplinary Core Idea:  

LS3 - Heredity:  Inheritance and variations

The performance expectations in LS3 help students formulate an answer to the question, "How do living organisms pass traits from one generation to the next?"

This lesson introduces students to genetic traits.  This lesson will give students the foundational knowledge to be able to successfully complete the following performance expectation and cross cutting concept:

  • MS-LS3-2. Develop and use a model to describe why asexual reproduction results in offspring with identical genetic information and sexual reproduction results in offspring with genetic variation. 
  • Cause and Effect:  Caused and effect relationships may be used to predict phenomena in natural systems.

Engage

5 minutes

To engage students in lesson I show students the following 4 pictures:

 

I give students 2 minutes to write down observations from all 4 pictures.  In addition I ask students to find any similarities or common theme amongst all pictures.  

The objective of this section of lesson is for students to begin to grasp the concept that there exists a variation of traits amongst members of a species.  Students will take an inventory of their own traits in the next section of lesson.

Explore

30 minutes

Students explore trait diversity by taking an inventory of their own easily-observable genetic traits. Working in small groups, they observe how their trait inventories differ from those of others. Students record their observations in a data table and make a bar graph to show the most and least common traits in the group. 

Learning Objectives:

  • Traits are observable characteristics that are passed down from parent to child. 
  • An individual will have many traits they share in common with others. 
  • An individual’s overall combination of traits makes them unique. 
  • Some traits are more common in a population than others. 

Materials

Prior Knowledge Needed

  • How to construct and read bar graphs 

Classroom Implementation

Activity instructions:

  • Begin activity by showing students pictures of all traits mentioned in activity, majority of students don't know what a widow's peak is for example.
  • Explain to students that traits are physical characteristics that are inherited from our parents. There are some traits that are more common amongst certain people (i.e. nationality, race, community, special population) compared to others.
  • Depending on class, students might complete inventory of traits in groups or you can complete it as a whole group.  Due to my high level of EL students I prefer to complete the inventory of the class as a whole group.  I go over each trait one by one and have students inventory each others traits.  
  • As we inventory traits we complete whole class data table.
  • Students create bar graphs of traits. (Teacher Note:  You will need to adjust bar graph handout since it is made for group data versus whole class).

Explain

10 minutes

In this section of lesson I show students a narrated presentation by the University of Utah's Learn Genetics titled What is a Trait?.  

Topics Covered

  1. Physical Traits
  2. Behavioral Traits
  3. Predisposition to a medical condition
  4. Dominant vs Recessive alleles
  5. Homozygous vs. Heterozygous
  6. Trait Inheritance

Students are required to take Cornell Notes during presentation.  

Cornell Notes provides students with another tool for organizing, reviewing and reflecting upon information received at school.

Elaborate

10 minutes

In this section of lesson students elaborate on what they have learned by completing a math extension of the Inventory of Traits activity completed earlier (MP4- Model with Mathematics).  In this math extension, students calculate the frequency of traits in their classroom, then compare their calculations with given frequencies for the general population

  • Depending on math level of students you might need to review how to calculate how percentages and in some cases long division if you don't allow calculators in the class room.
  • Model the frequency calculation of one trait so students can refer to this as they complete the remaining frequencies.

 

Evaluate

5 minutes

In this section of lesson students complete an Exit Slip using the CERC  (Claim Evidence Reasoning Conclusion) model that student have been practicing all year.  The writing task is for students to create a scientific explanation on genetic traits inheritance using evidence from lessons activities. (SP7 - Engaging in argument from evidence/W.7.1 - Write arguments to support claims with clear reasons and relevant evidence. (MS-LS2-4)