How do scientists know they're right? Truth be told, they don't always know. Explore the scientific process using mystery tubes in an insightful activity. Young scientists discover how to approach and solve problems in science, how ideas...

The complete original text of On the Origin of Species by Charles Darwin.

These pages are part of a site called "Evolution," that accompany a textbook by the same name. Mark Ridley is the author. This section is about Darwin, his travels, and his observations that led to "On The Origins Of Species."

Scientific article explaining what natural selection is, and how it manifests itself through genetics and from generation to generation. Natural selection is compared to genetic drift, both of which cause evolution to occur. The limits...

These pages are part of a site called "Evolution," that accompanies a textbook by the same name. Mark Ridley is the author. Here he discusses theories for species change that were before Darwin published "On the Origin of Species."

The expansion and explosion of a star is described at it goes through its nova phase. Current theories are discussed.