Homologous Structures and Superposition

Homologous Structures and Superposition

Homologous Structures

Organs or skeletal elements of animals and organisms, that due to their similarity, suggest a connection to a common ancestor. This is important because scientists can use this as evidence of evolution.

Multiple Choice

What is the most important aspect of homologous structures?

• sharing ancestors

• similar structure

• position of bones

• all of the above

Superposition

The Law of Superposition: The younger layers of rock are on top of the older layers of rock.

Multiple Choice

Which layer of rock is the oldest?

• A

• B

• C

• D

Multiple Choice

Which layer of rock is the youngest?

• A

• B

• C

• D

Digging into the past

Looking through rock layers can tell us about animals that lived in an area in the past. What kind of animals lived here?

Sedimentary Rock

is made of layers of sediment that are cemented and compacted over time.

Multiple Select

Which type of rock is most likely to have rock layers?

• Igneous

• Sedimentary

• Metamorphic

Fossils

By looking at the rock layers you can determine the time an animal lived.

Multiple Choice

Which type of fossil is oldest formed in the sedimentary rock?

• Mammals

• Trilobites

• Fishes

• Dinosaurs

• Amphibians

Multiple Choice

Which type of fossil is in the youngest layer?

• Trilobite

• Mammal

• Dinosaur

• Fishes

• Amphibian