Molecular & Cellular. Anatomy. Biology That Makes Us Tick: Free Stanford Course by Robert Sapolsky. 7.014 Introductory Biology. Exploring Life's Origins: Understanding the RNA World. The Complete Work of Charles Darwin Online. Biochemical Society. Genetics and the tree of life. We traditionally think about the tree of life in terms of Kingdoms: plants, animals, fungi, bacteria, etc.
Genetics has really revolutionized the way we think about the tree of life and, because our classifications should reflect ancestry (that is, who is more closely related to whom), it has actually called into question a lot of our traditional classifications. Most biologists split up life into three domains: Archaea, Bacteria, and Eucarya (the last of which includes animals, plants, fungi, etc.). The three domains of life. From Carl Zimmer's blog The Loom. Biodiversity Heritage Library.