In this lesson designed to enhance literacy skills, students learn about the varied physical and behavioral adaptations that animals rely on to help them survive changing environmental conditions, such as the arrival of winter.

This video segment adapted from NOVA reveals how junk DNA helped solve an evolutionary mystery: Why do certain species of fruit flies have wing spots while others don't?

The peacock provides a classic example of sexual selection, the force behind nature's extravagances. From Evolution: "Why Sex?"

Bonnie Chen builds on students' prior knowledge of mutations to lead her class through a simulation of wading birds feeding.

Marilyn Havlik leads students through a simulation of the Hardy-Weinberg Principle to develop their understanding of population genetics.

This interactive activity from A Science Odyssey offers a historic tour of 20th century home technologies.

In this video adapted from KUAC-TV and the Geophysical Institute at the University of Alaska, Fairbanks, learn how tectonic plate movement is responsible for building mountains, such as the Wrangell and St. Elias Mountains.

This interactive activity produced for Teachers' Domain shows the relationship between tectonic boundaries and the locations of earthquake events and volcanoes around the world.

In this transcript of an interview filmed for Evolution: "Great Transformations," Ted Daeschler and Neil Shubin describe the discovery and significance of some of their key fossil finds.

In this video adapted from Earth Island Institute, meet a high school student who educated her community about how a coal-burning power plant was contributing to asthma and other health problems there.

Why do teenagers act the way they do? This video segment from FRONTLINE: Inside the Teenage Brain explores the work scientists are doing to explain some of the mysteries of teenage behavior.

In this video adapted from Earth Island Institute's New Leaders Initiative, meet a high school student who worked to enact a state law to make cosmetics safer, after she learned they contained toxic chemicals linked to cancer.

Watch the ZOOM cast discover which insulator -- newspaper or aluminum foil -- is better at keeping an ice cube frozen longer.

In this video segment adapted from ZOOM, cast members show you how to make your very own electroscope. You can use it to find out if an object is electrically charged.

This illustration from Evolution by Monroe W. Strickberger shows the remarkable similarities between the bones in the forelimbs of various tetrapods, all of whose limbs serve very different functions.

This interactive activity from the NOVA Web site challenges you to think like Einstein and understand how time travel might be possible.

This video from NASA explains the process by which gamma-ray flashes associated with storms produce matter/antimatter particle pairs.

This illustrated essay from the NOVA Web site answers questions about irregularities in the tides.

In this lesson designed to enhance literacy skills, students learn that transitional fossils provide scientists with evidence to establish how major animal groups are related to one another.

This animation produced by WGBH and Digizyme, Inc. demonstrates the experimental technique used to introduce DNA plasmids inside bacterial cells, a process called bacterial transformation.