Morphology and Evolution
1. Consider how these organisms are related.
2. Working in groups of two or three, arrange
the images you were given. Organize them
according to evolutionary relationships.
Which is most closely related to Alligators?
A. Lizard
B. Bird
C. Bat
Which animal is most closely related to whales?
A. Hippo
B. Walrus
C. Shark
Which animal is most closely related
to the wolverine?
A. Tasmanian Devil
B. Rhino
C. Walrus
Which animal is most closely related to rhinos?
A. Walrus
B. Hippo
C. Zebra
Which is most closely related to Alligators?
A. Lizard
B. Bird
C. Bat
Hippos are most closely related to whales.
A. Hippo
B. Walrus
C. Shark
Walruses are most closely related
to wolverines.
A. Tasmanian Devil
B. Rhino
C. Walrus
Zebras are most closely related to rhinos.
A. Zebra
A. Walrus
B. Hippo
Arrange the animals listed below on the cladogram.
Alligator
Shark
Hippo
Zebra
Bird
Whale
Tasmanian Devil
Rhino
Justify your arrangement by placing a synapomorphy at
each of the grey bars. A synapomorphy is a feature that
is not found in animals that branch off prior to the node
(= fork) on the diagram, but which all subsequent animals
share. Use Pikaia as your outgroup (ancestral condition).
Even # Toes
Pikaia
Whales and Hippos both
descended from a common
ancestor that had an even
number of hoofed toes.
Possible Solutions
Even
Toes
Shelled eggs
Diapsid skull
Odd
Toes
Hooves
Live Birth
Fur/Hair
Synapsid skull
Legs
Pikaia
Jaws