All major groups of vertebrates are summarized here with the characteristics of each explained. Other subphyla of chordates are listed: cephalochordata, urochordata, monotremata, marsupialia. The details are relevant but are not linked...

Go deep in your paleontology unit with this spectacular set of slides! It introduces viewers to the types of fossils, a few famous fossils, and the geologic eras. This is done with easy-to-read text, diagrams, photos, and even videos. 

What is the difference between a shield volcano and a cinder cone volcano? How does the flow of lava influence the type of rock that's formed? A presentation on different aspects of volcanoes answers these questions for middle...