Avian Dinosaurs

What is a dinosaur that still lives among us today?

• a Sinornithosaurus

• an Archaeopteryx

• a bird

• a reptile

What does the author compare to living birds in this text?

• non-bird theropods

• living reptiles

• huge herbivores with small heads

• extinct birds

Read this sentence from the text.

"Based on the evidence of shared characteristics, scientists have concluded that birds are a type of theropod dinosaur."

What is a piece of skeletal evidence that supports the conclusion that birds are a type of theropod dinosaur?

• Birds brood their nests, just as non-bird theropod dinosaurs did.

• Feathers may have been used by non-bird dinosaurs in some of the ways that birds use their feathers today.

• The cerebrum in non-bird dinosaurs closely related to birds was very large.

• Birds and non-bird theropod dinosaurs have a hole in their hipbone.

Read this sentence from the text.

"Based on the evidence of shared characteristics, scientists have concluded that birds are a type of theropod dinosaur."

What is a piece of behavioral evidence that supports the conclusion that birds are a type of theropod dinosaur?

• Birds brood their nests, just as non-bird theropod dinosaurs did.

• The cerebrum in non-bird dinosaurs closely related to birds was very large.

• Birds and non-bird theropod dinosaurs have a hole in their hipbone.

• Birds and non-bird theropod dinosaurs have hollow bones.

What is the main idea of this text?

• The behavior of animals that have been extinct for a long time cannot be observed, and their DNA has been destroyed.

• Feathers were once thought to have evolved for flight, but now scientists think feathers may have originally served other purposes.

• Skeletal and behavioral evidence show that birds are dinosaurs, and brain evidence supports this conclusion.

• Scientists are using technology to reconstruct the inside of fossilized skulls and learn more about dinosaur brains.

What does the word "evolution" mean?

• a sudden and unexpected increase in size or amount

• a sudden and unexpected decrease in size or amount

• change that takes a day or two to happen

• change that happens over many generations

Choose the answer that best completes the sentence.

Bigger brains in primates prepared the way for them to walk on two legs. __________, bigger brains in dinosaurs prepared the way for flight.

• otherwise

• similarly

• for instance

• in particular