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Can selection happen without people?
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Predict 1 of 2: What do you think might have happened to the green anoles, once the brown anoles arrived in Florida and started to get hungry?




Predict 2 of 2: Not all of the green anoles are exactly the same. Which green anoles do you think the brown anoles are most likely to catch?

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Want to know more about how scientists study lizards?

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Extensions

Below are ideas for extending this topic beyond the activity & exploration which you just completed.
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Natural Selection Simulation

To show that selection can happen without people, play the Peppered Moth game. Here’s how:

  • Open the link. Click on and read “how to play” aloud. 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 moth population.
  • 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?
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Image & Video Credits

Mystery Science respects the intellectual property rights of the owners of visual assets. We make every effort to use images and videos under appropriate licenses from the owner or by reaching out to the owner to get explicit permission. If you are the owner of a visual and believe we are using it without permission, please contact us—we will reply promptly and make things right.

Exploration
Anole on rocks by JamieS93 , used under CC BY-SA
2 Anoles by numbers by Seadevil
tropical island by Christopher Michel , used under CC BY
brown geko by Michel Pierfitte , used under CC BY-SA
catching Anoles by Adam Algar
green geko by Tambako the Jaguar , used under CC BY-ND
white geko by Nick Hobgood , used under CC BY
Tokay climbing wall by Tokay Gecko
holding small Anole by txbowen , used under CC BY
green lizard with long tail by Melissa Gutierrez , used under CC BY-SA
Anole on log by Paul Hirst , used under CC BY-SA
lizard holding branch by L Church , used under CC BY
Cuban Anole by Thomas Brown , used under CC BY
cargo boat by Gerolf Drebes , used under CC BY-SA
large green lizard by Euku , used under CC BY-SA
fishermen by Anole Annals Blog
lizard on flowers by www.GlynLowe.com , used under CC BY-ND
Anole on pipe by Daniel Ramirez , used under CC BY
Print Prep
Activity Prep

In this Mystery, students learn about an example of how nature, not human beings, can slowly change the appearance of an animal using the process of selection. In the activity, Lizard Island, students simulate how natural selection affects a group of tree-climbing green lizards when their island is invaded by hungry brown lizards. This simulation only works for groups of 16 or more students. If you have a smaller group, use the Small Group Version of this activity found in Prep Instructions.

Preview activity

Number of students:
Adopt A Lizard worksheet 1 per 3 students
Baby Lizard worksheet 1 per pair
How Many Lizards? worksheet 1 per student
Prep Instructions

If you have a smaller group (between 1 to 15 students), you need to use the Small Group Version of this activity. This version has step-by-step activity instructions on the printout. The step-by-step in the Mystery can be used for groups of 16+ students.

Don’t Throw Away Extra Adopt A Lizard Cards

There are three types of lizards in the activity simulation -- Not-So-Good Climbers, Good Climbers, and Excellent Climbers. It’s important that the simulation begins with an equal number of these lizard types. So, if the number of students in your classroom isn’t divisible by 3 (e.g. 28 students), then you will have a few extra Adopt A Lizard Cards printed out. Have students who finish quickly fill out these extra Adopt A Lizard cards.

Prep Baby Lizard Cards

Each student needs a half sheet of the Baby Lizard Cards. Cut each Baby Lizard page in half before class.

Extensions