MISSION 2 — Eating Dinosaurs for Dinner
Has anyone ever told you that dinosaurs aren’t extinct? It’s true! They aren’t. But how can that be? There are no T. rexes at the zoo, or Triceratopses roaming the plains. This level holds the key to understanding where today’s dinosaurs are hiding—on our farms, in the trees, and on our dinner plates.
Play "Eating dinosaurs for dinner" and answer questions 3–5 after you've completed that level.
3-4. Click the button below to answer questions 3-4. Remember to refer to your completed tree and the species comparison tab if you are not sure of your answers.
5. A clade is a fancy word for any group in a phylogenetic tree that includes an ancestor and all of its descendants. A simplified dinosaur tree is to the right.
Imagine that you have a pair of scissors and can cut the tree. You can tell a group is a clade because it would only take one “snip” to make the group “fall off” the tree. Five different clades have been marked on the tree with brackets.
The clade marked 1 is clade Aves—the birds. The clade marked 2 is clade Theropoda—the theropods. Clades 2 and 3 are the two major groups of dinosaurs—clade Saurischia and clade Ornithischia. Finally, clade 5 is clade Dinosauria—the dinosaurs.
a. Mark on the tree using numbers 2–4 where you can “snip” off each clade. Numbers 1 and 5 have been done for you. Use the "Visualize It" tool below.
b. Triceratops belongs to two of the marked clades on this tree: 4 and 5. This means that Triceratops is both an ornithischian (clade 4) and a dinosaur (clade 5). Which clades do birds belong to?
c. Use your answer to part b to explain why birds are dinosaurs.
