The aim of this article is to relate the history of oxygen in the atmosphere to the evolution of photosynthesis, aerobic respiration, mitochondria, and life on earth.

[Free Registration/Login may be required to access all resource tools.] Vascular seedless plants have vascular tissue but do not have seeds. Most of the large vascular seedless plants from ancient times are now extinct, but their smaller...

Come and learn more about how to incorporate embryology into your classroom. This site features tons of information about the embryology of chickens.

The aim of this article relates the nature of science to our current understanding of the origin of life and describe the formation of the atoms which build the Earth and its life.

[Free Registration/Login may be required to access all resource tools.] Describes the Earth's formation.

Part of PBS-NOVA Online. An excellent explanation of how radiocarbon dating is done and why it works. Great material for earth science, history or biology classes.

This is the centralized site for information about all AP courses offered by College Board. It contains information for students and teachers about each of the AP courses (almost 40 in all), including a course description and relevant...

This online exhibit demonstrates how human vision works and has influenced Western art. It combines the biology of vision and art history. The exhibit focuses on the eye and its response to color and contrast while highlighting several...

The life and philosophical treatises of Aristotle (384-322 BCE) are surveyed, including his writings on biology, zoology and physics.

This site describes the Museum of Natural History and Science in detail and provides links to other programs and exhibits offered.

This site from USGS provides several activities to help understand the interrelationships among earth surface processes, ecological systems, and human activities. Also included are links to new findings and programs concerning Earth...

Discover Magazine brings you the world of science: the latest research news, enhanced versions of articles, and a full-text archive.

Links to many video-clip based lessons in the areas of health, English language arts & drama, mathematics, music, biology, earth science, inventions, astronomy, physics, chemistry, U.S. history and culture, and world history and...