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This Click & Learn traces the flow of energy from the Sun all the way to cells within organisms. The embedded questions and calculations guide students’ understanding of how energy is distributed through a variety of ecosystems.

This interactive module allows students to collect and analyze data from a virtual river to construct biomass and energy pyramids.

This interactive module explores how mutations arise in germline and somatic cells. It also shows how these mutations can lead to genetic conditions, such as cystic fibrosis and cancer.

This interactive module explores examples of how changes in one species can affect species at other trophic levels and ultimately the entire ecosystem.

This film tells the story of the ecologists who first documented the role of keystone species in ecosystem regulation.

This animation shows how varying concentrations of a signaling molecule activate different transcription factors to determine cell fate.

This animation shows how stem cells from early mammalian embryos can be grown and studied in a laboratory.

This animation describes the formation and fates of the three germ layers in a human embryo.

This animation shows how salamanders can replace missing limb tissues with the help of cells similar to stem cells.

This animation shows how tumors use the protein VEGF to recruit blood vessels.