A structure found in ONLY 1 GROUP of organisms

• Diagnostic structure

• Shared structure

• Evolved structure

• Common structure

What DIAGNOSTIC STRUCTURE is only found in reptiles?

• Backbone

• 1, 2, many bone structure

• Skull with 2 extra holes behind the eye

• 4 limbs

Is the mystery fossil closely related to a crocodile?

• Yes. They both have a skull with two extra holes behind the eye.

• No. Its skull does not have two extra holes behind the eye.

Is the mystery fossil closely related to a spinosaurus?

• Yes. They both have a skull with two extra holes behind the eye.

• No. Its skull does not have two extra holes behind the eye.

What DIAGNOSTIC STRUCTURE is only found in mammals?

• Different types of teeth

• 1, 2, many bone structure

• Skull with 2 extra holes behind the eye

• 4 limbs

Is the mystery fossil closely related to wolves?

• Yes. They both different types of teeth, a diagnostic structure for mammals.

• No. Its does not have different types of teeth, a diagnostic structure for mammals.

What SHARED STRUCTURE is found in both the mystery fossil and the whale?

• An ELONGATED SKULL

• A BLOWHOLE

• A POINTED CREST at the back of the skull

• A special ARCH where powerful jaw muscles attach

What SHARED STRUCTURES are NOT found in both the mystery fossil and the wolf?

• Special ARCHES where powerful jaw muscles  attach

• A CREST where powerful jaw muscles  attach

• FORWARD EYE PLACEMENT to track prey

• An ELONGATED SKULL

Which species' SKULL SHAPE is most similar to the mystery fossil's?

• The WHALE's skull is most similar. They both share an ELONGATED SKULL.

• The WOLF'S SKULL is most similar. They both share a CREST, ARCHES, and FORWARD EYE PLACEMENT.

Which species' NOSTRIL is most similar to the mystery fossil's?

• The mystery fossil's nostril is SHIFTED BACK on the skull, like the whale's BLOWHOLE.

• The mystery fossil's nostril is closer to the front end of the skull, like the wolf's.