This interactive simulation allows students to explore two classic mathematical models that describe how populations change over time: the exponential and logistic growth models.

This interactive module explores methods used to survey large animal populations, and what they have revealed about the current state of the African elephant population.

This interactive module explores the phases, checkpoints, and protein regulators of the cell cycle. The module also shows how mutations in genes that encode cell cycle regulators can lead to the development of cancer.

This tutorial describes the structure and function of the cancer-causing protein BCR-ABL. It also shows how drugs targeting this protein can help treat chronic myeloid leukemia (CML), a cancer of the white blood cells.

This interactive timeline explores the history of Gorongosa National Park in Mozambique.

This model shows the structure of the protein BCR-ABL, which causes a type of cancer called chronic myeloid leukemia.

This model shows a mutated form of the cancer-causing protein BCR-ABL that is resistant to the drug Gleevec.

This model shows the structure of ATP, a molecule that provides energy for cellular processes, including protein phosphorylation.

This interactive module examines Earth’s past and present climate, highlighting the effects of two important factors: solar radiation and the composition of the atmosphere.

This interactive module explores how the changes in oxygen levels throughout Earth’s history have impacted the planet’s environment and types of life.

This tutorial describes the various forms of “fat” — from a tissue, to a cell type, to a class of molecules.

This tutorial explores how fat is digested, transported, stored, and used for energy.