Reading Cladograms

Science · Dinosaurs & Paleontology · ages 9-11

Name ______________________ Date ____________

On a cladogram, dinosaurs that share more features are drawn farther apart from each other.
Circle one: True False
What does a cladogram show?
- How tall each dinosaur was
- How dinosaurs are related based on shared features
- How much each dinosaur weighed
On a cladogram, what does a branch point represent?
- A single animal
- Shared ancestor
- A missing fossil
This chart shows how many features each pair of dinosaurs shares. Which pair is most closely related?
- Rex and Raptor
- Rex and Stego
- They are equally related
In a cladogram, Deinonychus and Velociraptor branch off from the same point close to the tips. Stegosaurus branches off much earlier. Which two dinosaurs are most closely related?
- Deinonychus and Stegosaurus
- Velociraptor and Stegosaurus
- Deinonychus and Velociraptor
A partly finished cladogram already has two groups: 'feathers and hollow bones' and 'bony plates on the back'. A new dinosaur has feathers and hollow bones. Where should it attach?
- With the feathers and hollow bones group
- With the bony plates group
- On its own branch with no group
A cladogram shows Triceratops and Stegosaurus branching off from the same recent point, both branching earlier than T. rex. Which sentence about them is correct?
- Triceratops and Stegosaurus are the most closely related pair
- T. rex is more closely related to Triceratops than to Stegosaurus
- All three dinosaurs are equally related
A new dinosaur has sharp claws and feathers, like Velociraptor, but no plates like Stegosaurus. Mia adds it next to Stegosaurus because they are both large. What did Mia get wrong?
- She should have used shared features, not size, to decide
- She should have ignored feathers entirely
- She should have added a whole new column

Answer key

For grown-ups. Fold this page away before handing over the rest.

Reading Cladograms W1-mt_cSPtyLF3q1-s1

False · The opposite is true. Dinosaurs that share more features branch off closer together.
How dinosaurs are related based on shared features · A cladogram is built from shared features, not size or weight.
Shared ancestor · A branch point is where two groups split apart from one shared ancestor.
Rex and Raptor · Rex and Raptor share more features, so their branches meet closer together than Rex and Stego.
Deinonychus and Velociraptor · Deinonychus and Velociraptor branch off from the same point close to the tips, so they share the most recent common ancestor.
With the feathers and hollow bones group · The new dinosaur matches the feathers and hollow bones group, so it belongs on that branch.
Triceratops and Stegosaurus are the most closely related pair · Triceratops and Stegosaurus split from the same recent branch point, so they are the most closely related pair here.
She should have used shared features, not size, to decide · Cladograms group animals by shared features, not by size. Mia should compare the features list instead.