NASA
Nasa: Image Science Center: Ask the Space Scientist Earth
Site from NASA contains a collection of 91 questions pertaining to the Earth's atmosphere, magnetic field, ionosphere, rotation and origin of life.
BiologyWise
Biology Wise: Biogenesis Theory
The biogenesis theory is explained and how it differs from the theory of spontaneous generation. The work of early scientists to prove or disprove these theories is described, including discoveries in microbiology. Louis Pasteur is...
Khan Academy
Khan Academy: Glossary: The Future
A helpful glossary to terms in the Big History Project.
City University of New York
Exploring Life: The First Cells
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.
University of Kentucky
University of Kentucky: Earth Science Classroom Activities
A collection of links to activities and lessons that could be used for Earth science concepts including the foil record, creating a timeline of Earth's history, plate tectonics, dinosaurs, and the progression of life on Earth.