Animation Description
In this animation, graphics of seven animals, shark, tuna, frog, human, hare, caiman, and parrot, are connected by a branching evolutionary tree beneath them. An arrow shows that time progresses in the upwards direction on the tree. On the tree, starting from the root, the branch leading to the shark splits off first to the left, then the branch leading to the tuna splits off to the left, and then the branch leading to the frog splits off to the left. Then a branch splits off to the left that itself splits into two, leading to the human and hare. The last branch, which extends up and to the right splits into the caiman and parrot branches. Six orange dots are on the tree, one at each point that a branch splits. The parrot and tuna graphics are highlighted. The parrot is at the far right side, and the tuna is in the second from the leftmost position. When the orange dot second from the bottom, the one at which the tuna splits off onto its own branch, is clicked, the dot is labeled "common ancestor" and colored highlighting appears on the tree. Red highlighting extends upwards on the tree from the common ancestor to the tuna graphic, and also traces the path upwards from the common ancestor to the parrot graphic. This highlighting is labeled "distinct histories." Purple highlighting extends downwards and traces a path from the common ancestor to the root of the tree. This highlighting is labeled "shared history." When any other dot is clicked, the reader is instructed to "try again."
Animation Text
Panel 1
Click on the orange dot that best shows where the tuna and parrot's common ancestor existed.
Panel 2
Incorrect trigger response: Oops. Follow each lineage back to the point where they meet. Try again.
Panel 3
Correct response: Correct! By following the lineages back to where they intersect you find their point of common ancestry.