Earth Space Science Chapter 13 SHORT

sunday 10.1.26

How old is Earth?

About 4.6 billion years old.

What is Precambrian Time?

The largest time span of Earth's history.

What are shields?

Large exposed areas of Precambrian rock.

What was Earth's early atmosphere made of?

Water vapor, carbon dioxide, nitrogen, and trace gases, but no oxygen.

How did Earth's early atmosphere and oceans form?

Gases escaped from molten rock; cooling caused water vapor to condense into oceans.

What organisms added oxygen to Earth's atmosphere?

Cyanobacteria.

Why are red beds and banded iron formations important?

They show oxygen was becoming abundant.

When did the first evidence of life appear, and how old are the oldest known fossils?

Evidence: about 3.8 billion years ago; fossils: about 3.5 billion years old.

What are stromatolites?

Layered structures made by cyanobacteria.

Which evolved first, prokaryotes or eukaryotes?

Prokaryotes; they have no nucleus, while eukaryotes do.

What is the order of the major eras?

Precambrian, Paleozoic, Mesozoic, Cenozoic.

How long did the Paleozoic Era last?

About 300 million years.

When did abundant fossil evidence begin?

About 540 million years ago.

What is a mass extinction?

When many species become extinct in a short time.

What was the Cambrian Explosion?

Many new types of animals appeared and quickly diversified.

Where did most Paleozoic life live, and how did hard parts help?

Life was mostly in oceans; hard parts gave protection.

What made up Gondwana?

South America, Africa, Australia, Antarctica, and parts of Asia.

What made up Laurasia?

North America, Europe, and northern Asia.

What happened during the Ordovician and Silurian?

First land plants evolved; much of North America was covered by shallow seas.

What was the Devonian Period known for?

The Age of Fishes; amphibians became early land vertebrates.

What happened during the Carboniferous?

Coal swamps formed and the first reptiles evolved.

When did Pangaea form?

During the Permian Period.

What happened at the end of the Permian?

The largest mass extinction in Earth's history.

What are the three periods of the Mesozoic Era?

Triassic, Jurassic, and Cretaceous.

What is the Mesozoic Era called?

The Age of Reptiles.

What group do dinosaurs belong to?

Reptiles.

What happened during the Triassic?

Pangaea began breaking apart, gymnosperms were common, and the first mammals appeared.

What major tectonic event began about 200 million years ago?

The breakup of Pangaea.

What happened during the Jurassic?

Pangaea continued splitting and dinosaurs became very diverse.

What were ichthyosaurs and plesiosaurs?

Large marine reptiles.

What animal links dinosaurs and birds?

Archaeopteryx.

What happened during the Cretaceous?

Flowering plants evolved and dinosaurs remained widespread.

What caused the Cretaceous mass extinction?

A large meteorite or asteroid impact near the Gulf of Mexico.

How could the meteorite impact cause mass extinction?

Dust blocked sunlight, temperatures dropped, plants died, and food chains collapsed.

What is the Cenozoic Era called?

The Age of Mammals.

How are mammals different from reptiles?

Mammals are warm-blooded and have hair or fur; reptiles are cold-blooded.

Why can mammals live more active lives than reptiles?

They can maintain a steady internal body temperature.

What caused major mountain building during the Cenozoic?

Plate tectonics; ranges included the Rockies, Alps, and Himalayas.

What happened during the Tertiary Period?

Grasses spread across plains and mammals became more diverse.

What period, era, and eon are we in today?

Quaternary Period, Cenozoic Era, Phanerozoic Eon.

What are Milankovitch cycles and what do they help explain?

Changes in Earth's orbit and tilt that help explain ice ages.

What happened to many large mammals near the end of the last ice age?

They became extinct, possibly from climate change and human hunting.