Heterodontosaurus ("different-teeth-lizard") was one of the earliest ornithischian dinosaurs. This lightly built, bipedal dinosaur was collected in 1966 from the 200 million year old Lower Jurassic Upper Red Beds, Stronberg series, on the northern slopes of the Krommerspruit Mountain near Voisana, Republic of South Africa. It is in the family Heterodontosauridae. This description of their classification, ... Full description.

Ceratopsians were ornithischians, or "bird-hipped" dinosaurs, such as the well known Triceratops. Forms without the enormous horns and frills of Triceratops, in the family Protoceratopsidae, include the Mongolian genus Protoceratops and the unusual bipedal, frill-less dinosaur Psittacosaurus ("parrot-lizard"). This description of their classification, morphology, locomotion, and eating habits also ... Full description.

The Thyreophora are a group of small to quite large armored plant-eating dinosaurs. The most familiar are Stegosaurus and Ankylosaurus, though there were many others. The two earliest known, Scutellosaurus and Scelidosaurus along with the remaining two major groups Stegosauria and Ankylosauria are described on this site. Full description.

Users of this activity view a photograph of a fossil, read a brief description and are invited to guess its name. The name is revealed with another click and further information about the fossil is furnished. A new mystery fossil is added to the site each month. Full description.

This site describes sabretooth animals of the Cenozoic Era. The sabretooth morphology has appeared several times during the history of mammals. Sabre-toothed members of the Carnivora appeared independently at least twice. Sabre teeth evolved both among the true cats, or the family Felidae (these sabre-toothed cats are sometimes classified in a separate subfamily of cats, the Machairodontinae) and ... Full description.

Evidence presented on this site is overwhelmingly in favor of birds being the descendants of a maniraptoran dinosaur, probably something similar (but not identical) to a small dromaeosaur. Dr. Jacques Gauthier created the first well-accepted, detailed phylogeny of the diapsids. His work provided strong, compelling support for the theory that birds are theropod dinosaurs. The development of the theory ... Full description.

This student guide provides an introduction to the types and value of tropical forests, deforestation, the practice of forestry, forestry research, and tropical forestry. The guide shows how modern practices can help stem the tide of forest destruction while continuing to provide valuable products for people. Examples of sustainable forestry are cited, which could be used as models for protecting ... Full description.

This lesson uses the 3.6 million year old tracks of early hominids in Laetoli to provide a tantalizing opportunity to explore how scientists use patterns of the present to understand the past. What do those footprints tell us? How can we find out? Students measure and correlate their foot lengths and body heights, then use this data to estimate the height of Laetoli hominids. Full description.

In this lesson, students read and discuss selected and edited excerpts from the essays of Stephen Jay Gould on the subject of contrivances. Students learn that many features of modern organisms reflect the structure of their ancestors in ways that are not adaptive. They also learn that one of the best indicators of evolution is not the examples of perfect adaptations, but of the relatively imperfect ... Full description.

In this lesson about speciation and its role in evolution, different subspecies of a California salamander are placed on a grid map of California according to where samples were collected. Discussion focuses on patterns of their distribution, their likely evolutionary relationships, and probable sequence of formation from the original form (speciation). Full description.