Learn about the endosymbiotic theory. This theory explains the evolution of cells from a mitochondria and chloroplast working together in a symbiotic relationship to the current cell structure.

Through full-color images and concise information, learn about the origin of cells. Discover some of the notable studies surrounding the history of life on Earth.

Use the scientific reasoning and critical thinking to take an in-depth look at the basics of biology.

A brief essay about older and more recent ideas on when the first cells evolved. Good coverage of different scientific theories about the origin of life.