PBS Geologic Time

Which scientist developed the first laws of stratigraphy, the science of interpreting rock layers?

• William Smith

• Giovanni Arduino

• Nicolas Steno

• Charles Darwin

What was a key characteristic of the Hadean Eon?

• The first appearance of complex multicellular life.

• The Earth's crust was cooling, leading to continent formation.

• The atmosphere was rich in oxygen due to photosynthetic bacteria.

• The planet was a searing wasteland with volcanic activity and cosmic bombardments.

What significant event occurred during the Archean Eon that led to a major change in Earth's atmosphere?

• The formation of the first continents.

• The appearance of cyanobacteria, which released oxygen.

• The development of the first eukaryotes.

• Widespread volcanic activity melted most of the rock.

What type of organisms developed during the Proterozoic Eon, characterized by cells with a nucleus and membrane-wrapped organelles?

• Cyanobacteria

• Stromatolites

• Eukaryotes

• Trilobites

Are you enjoying the video lesson?

• Yes

• No

Which of the following eons are collectively known as the Precambrian?

• Hadean, Archean, and Proterozoic

• Paleozoic, Mesozoic, and Cenozoic

• Phanerozoic and Proterozoic

• Archean and Mesozoic

What types of organisms first populated the land during the Paleozoic Era?

• Fish and placoderms

• Amphibians and reptiles

• Plants and arthropods

• Mammals and birds

What percentage of marine species disappeared from the fossil record during "The Great Dying" at the end of the Paleozoic Era?

• 50%

• 70%

• 96%

• 100%

What is considered the primary cause of the Cretaceous-Paleogene (KPG) Extinction Event?

• Massive volcanic eruptions

• A giant asteroid impact

• Rapid climate warming

• The rise of mammals