Learn what an ecosystem is, how energy and matter move through ecosystems, and what makes an ecosystem stable.

Learn about cooperation and "multicellularity" in prokaryotes including mutualisms, commensalisms, parasitisms. Also find out the role of prokaryotes in the carbon and nitrogen cycles.

See how ecosystems are organized into several different levels, and an ecosystem can be studied at any one of the various levels of organization.

Learn about the many types of symbiotic relationships in an ecosystem.

Understand the predator-prey relationship in an ecosystem.

See how organisms each have their own role in the ecosystem.

Tillena Lou and her siblings spend a lazy day imagining what it might be like if they were other types of animals. What would they need to survive? Synopsis: Tillena Lou explores her home and discovers interesting things about the...

Learn about the importance of many mammals to humans.