Natural Selection

Students read about the environmental conditions of two fictional planets. Student groups consider hypothetical adaptations that would allow humans to thrive on one of these planets. In the future, the changed humans will return to earth and explain how adaptations and natural selection caused them to have a few new traits.

Read the explanation at the top of the page aloud to the class. Then, read the descriptions of Planet X and Planet Y.

Ask students to discuss the illustrations with a partner.

Idioms:

Many students may have heard the term “pitch black” when someone describes an environment where there is no light, like a cave or basement without windows. But many students may not know that pitch is a tar-like substance that is usually very black or dark in color. Pitch was used to seal seams in ships or houses.