Animation Description
This animation begins with a line drawing of a caiman skeleton with the front right foot highlighted in yellow. When the foot is clicked, we zoom in on the foot and the rest of the skeleton disappears. We can now count the digits on the foot, which are labeled with the numbers 1 to 5. When the word "more" in the right panel is clicked, a line drawing of a parrot skeleton with the bones at the end of the right wing hightlighted appears. When the wing is clicked, we zoom in on the wing tip and the rest of the skeleton disappears. We can now count the digits on this limb; there are only three, labeled 1 to 3. When the word "more" in the right panel is clicked, a line drawing of a T. rex skeleton with the right hand hightlighted appears. When the hand is clicked, we zoom in on the hand and the rest of the skeleton disappears. We can now count the digits on this limb; there are only three, labeled 1 to 3. A multiple choice question appears in the right panel. When "b) loss of two fingers" is clicked, a success message appears. When any other option is clicked, the user is instructed to "Try again." This tells us that T. rex has inherited the loss of two fingers, like the parrot has.
Animation Text
Panel 1
Let's count the number of fingers each animal has on its hand. Start by clicking on the caiman's hand for a close-up view.
Panel 2
The caiman, like all crocodiles, has five fingers.
Panel 3
Click on the parrot's hand to zoom in and examine it.
Panel 4
Birds have inherited a lack of two fingers.
Panel 5
Now let's examine T. rex. Click on its hand to take a closer look.
Panel 6
Which of these conditions did T. rex inherit?
a) All five fingers intact
b) Loss of two fingers
c) We can't tell
Answers:
a) All five fingers intact: Oops. Look closely at the hands of T. rex. How many fingers do you see? Try again!
b) Loss of two fingers: Good job! Like the parrot, T. rex has inherited fewer fingers.
c) We can't tell: Oops. Look closer at the heel-bone of T. rex.