This lesson will review the difference between autotrophs and heterotrophs, and show how both play important roles in a food web. It is 2 of 4 in the series titled "Autotrophs vs. Heterotrophs."

[Free Registration/Login may be required to access all resource tools.] When an herbivore eats a plant, the energy in the plant tissues is used by the herbivore. Every time energy is transferred from one organism to another, there is a...

Explore the different ecological roles of organisms in the ecosystem, and find out how the energy flows through them.

[Free Registration/Login may be required to access all resource tools.] Describes how energy is transfered from one organism to another.

This is a teacher's guide to a lesson on ecosystems. The objective is for the students to set up their own ecosystem and define the roles of producers, consumers and scavengers.

[Free Registration/Login may be required to access all resource tools.] Describes how energy is transfered from one organism to another.

This lesson will review the difference between autotrophs and heterotrophs, and show how both play important roles in a food web. It is 3 of 4 in the series titled "Autotrophs vs. Heterotrophs."

[Free Registration/Login may be required to access all resource tools.] About 10,000 bird species belong to 29 different orders within the class Aves. The diversity among birds is striking. Birds can vary greatly in size and color. Some...

This website describes trophic levels, transfer of energy between trophic levels, pyramids of ecology, and nutrient cycles within the environment.

[Free Registration/Login may be required to access all resource tools.] Why do you need air to live? Of course if you didn't breathe, you couldn't survive. You need the gas oxygen to perform cellular respiration to get energy from your...

Join Ellen on her trip to the Kaap De Goede Hoop in South Africa, and learn more about plants, animals, and energy.

[Free Registration/Login may be required to access all resource tools.] Describes the different roles in an ecosystem.

Lesson looks at the definition of an ecosystem, biogeochemical cycles, and factors responsible for the differences between ecosystems.

Take this interactive, multiple-choice quiz over concepts in ecology, then review your score and any missed questions at the end.

[Free Registration/Login may be required to access all resource tools.] Humans could not live on Earth if it were not for protists. Why? Protists produce almost one-half of the oxygen on the planet, decompose and recycle nutrients that...

This overview of feeding relationships illustrates to students the trophic levels of different organisms in an ecosystem. Hover the mouse over different terms to see their definitions.