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Notes for teachers

Cultural Note: Our school is involved in a literacy partnership wherein an adorable labradoodle “Milo” visits 3x weekly to read with students. This prompted me to design a lesson plan about selection: artificial (as in dog breeding) and natural (the anole lizards). This topic or theme may not be suitable for all 3rd graders, but our students were very fascinated.

List of Materials

Video Anole Lizards in Puerto Rico [stop at 3:33]
Video Anole Lizards in Florida
Lizard Toe images
graph paper
calculators (optional)

This lesson can be found on MysteryScience, but I have made several adaptations for my students.

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Standards

NGSS

3-LS3-1. Analyze and interpret data to provide evidence that plants and animals have traits inherited from parents and that variation of these traits exists in a group of similar organisms.

3-LS4-2. Use evidence to construct an explanation for how the variations in characteristics among individuals of the same species may provide advantages in surviving, finding mates, and reproducing.

3-LS4-3. Construct an argument with evidence that in a particular habitat some organisms can survive well, some survive less well, and some cannot survive at all.

AZ Science Standards

3.L2U1.6: Plan and carry out investigations to demonstrate ways plants and animals react to stimuli.

3.L1U1.5: Develop and use models to explain that plants and animals (including humans) have internal and external structures that serve various functions that aid in growth, survival, behavior, and reproduction.

AZ Math Standards

3.NBT.A Use place value understanding and properties of operations to perform multi-digit arithmetic.

3.MD.B Represent and interpret data.

Standards

Scientific & Engineering Practice (SEP)

Planning and Carrying Out Investigations

Analyzing and Interpreting Data

Engaging in Argument from Evidence

Disciplinary Core Ideas (DCIs)

LS3.A: Inheritance of Traits

LS3.B: Variation of Traits

LS4.B: Natural Selection

LS4.C: Adaptation

Crosscutting Concepts (CCCs)

Cause and Effect

Systems and System Models

Stability and Change

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Objective(s):

Learning Intentions (Key Concepts that students will be learning):

Today I am learning how nature, not human beings, can slowly change the appearance of an animal using the process of selection.

Performance Expectation (Success Criteria):

I am successful when I can simulate how natural selection affects a group of tree-climbing green lizards.

Students compare the structures and functions of traits that enable organisms to survive in a specific environment. Analyzing the traits of animals provides evidence for how those traits vary, how they are inherited, and how they have changed over time through selection. Students also examine how the environment can affect inherited traits and determine which animals will survive in a particular environment.

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Agenda (40-45 minutes)

Engage (7 minutes)

Explore: hands-on activity (20 minutes)

Explain (5 minutes)

Extend or Elaborate (10 minutes)

Evaluate (3 minutes)

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Intro/Driving Question/Opening

Natural selection favors those traits that enable populations to live successfully in a particular habitat.

Engage: You will show 2 video clips that demonstrate the habitat and structures of an anole lizard.

Video 1 : Video Anole Lizards in Puerto Rico [stop at 3:33]
Video 2: Video Anole Lizards in Florida

Students will learn that many kinds of lizards have a similar trait: toes with special scales that grip too. Having lots of these toe scales can be really important for a lizard. Climbing is more than a fun sport for them. It can be a matter of life and death. Think about that for a moment.

Ask: How could being a good climber help a lizard survive?

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Hands-on Activity Instructions

Suggested group structure: Students NEED to be in groups of 4 for this activity.
Explore: Give each student a picture of a lizard toe on a card with a close-up of the lizard's toe pads. I used Google to search for different images or you can use these.
Students will count the number of toe scales. As a class, create a graph of the numbers of toe scales on the toe pads.

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Activity (cont.)

Create a line plot graph using students’ qualitative data. Students will begin to see that lizards with more toe scales are better at climbing.
Create a bar graph of the number of excellent climbers vs. those that are not excellent climbers.
Pose the scenario: What if an excellent climber and a not so good climber were to have a baby?

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Assessment

Why are the green anoles such good climbers?

The green anoles are such good climbers because… a. they like climbing trees. b. they need to be able to climb to get food that is high up in the trees. c. they need to be able to get away from brown anoles on the ground. d. the green anoles that were poor climbers were more likely to get eaten by brown anoles, so they had fewer babies.

A scientist discovered two species of anole lizards that live in different habitats and display the characteristics listed in the table on the next slide. (The scientists based these observations on a sample of 20 lizards from each species.) Describe the differences you see in the 2 lizard species.

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Assessment (cont)

Observations of Two Species of Anoles
Species	A	B
Habitat	High trunks and branches	Lower trunk and ground
Body length	130-191 mm	55-79 mm
Limb (arm/leg) length	Short	Long
Toe-pad size	Large	Intermediate
Color	Green	Brown
Tail length	long	long

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Differentiation

Students can brainstorm solutions on ways to help other animals. In situations where human activity has created problems for wildlife, scientists and engineers often figure out changes that people can make to help.

Here are a few examples to give you an idea of the range of possible solutions.

● In Louisiana, where invasive species are a problem, one chef came up with recipes to encourage people to eat the invaders.

● In Florida, where tegu lizards from Argentina are threatening local species, some people are catching the tegu lizards and selling them as pets.

● In Arizona, where a major highway blocked the migration route of bighorn sheep, people built “sheep bridges” that let the animals cross high above the busy road.

Remediation

Extension/Enrichment

Peppered Moth Online Simulation:

Natural Selection Simulation

To explore another example of trait variation and survival, play the Peppered Moth game. Here’s how:

Open the link. Click “how to play” and read aloud. The trait of wing color varies with these moths. At the start of the game, half the moths are light-colored and half are dark.
Click “play game.” Choose to hunt for moths among trees with pale bark or trees with dark bark. Before choosing, ask students whether they think the color of the tree’s bark will make any difference to the the moth's survival.
Make your choice. Suddenly, you’re a hungry bird, pecking at moths. In the upper left corner, you’ll see a timer and a count of how many moths you’ve eaten. Down below, you’ll see graphs that show how you have affected the moth population.
When the game ends, make a note of how the moth population changed. Then play again. This time choose the other type of forest. Once again, at the start, half the moths are light colored and half are dark. Note the results of the game.
Discuss as a class: How would you explain these results?