Why Don't Whales Have Legs?

Here is a fascinating cross-curricular lesson that investigates how limited genetic variation may have increased the prevalence of a rare genetic disease among the Navajo tribe.

Does the human body evolve as quickly as human culture? With a stellar 15-minute video, explore the trait of lactose intolerance. Only about 1/3 of human adults seem to still have the enzyme lactase and therefore, the ability to digest...

Tardigrades are microscopic organisms (0.5 mm long) with segmented bodies and four pairs of legs, each with four to eight claws. The narrator of this video explores tardigrades, organisms that can survive the most extreme environments...

As we get older, we age, our bodies and minds deteriorate, but this isn't true of all species. The video begins with why we age and what biological processes cause aging. Then it covers research on worms, mice, and other animals that...

Students identify two types of whales: toothed whales and baleen whales, and understand that whales come to the surface for air. Then they recognize that whales are mammals (they nurse their young and are warm-blooded). Students also...

With leaves as their main source of diet, sloths don't particularly gain a lot of energy when they eat. But how do they maintain such slow lives? Watch a video that explains why sloths are so slow.

Our bodies simply aren't built for such a sedentary existence. Discover what happens to our bodies when we don't practice what we are built to do—move!

What would be the best place to live on Mars? A fascinating look at the geographical of Mars is sure to intrigue the future astronomers in your middle or high school class. A short video introduces learners to the different...

Although little is know about why whales sing, researchers are developing theories that explain how whales are able to vocalize. Viewers get a short course in whale song and even get to listen to recordings of the haunting melodies...

Is it true that larger animals have longer lifespans than smaller animals? Does an animal's habitat help shape the length of its life? And does the ability to adapt and evolve allow living things to expand their lifespans? Watch a video...