Earth Space Science Chapter 13

sunday 10.1.26

How old is Earth?

About 4.6 billion years old.

What is the largest time span of Earth's history?

Precambrian Time.

What are shields?

Large exposed areas of Precambrian rock.

What gases were in Earth's early atmosphere?

Water vapor, carbon dioxide, nitrogen, and trace gases.

Was oxygen in Earth's original atmosphere?

No.

How did Earth's early atmosphere form?

Gases were released from molten rock and volcanic activity.

How did Earth's oceans form?

Earth cooled and water vapor condensed into liquid water.

What organisms helped add oxygen to Earth's atmosphere?

Cyanobacteria.

Why are red beds and banded iron formations important?

They show that oxygen was becoming abundant.

When did the first evidence of life appear?

About 3.8 billion years ago.

How old are the oldest known fossils?

About 3.5 billion years old.

What are stromatolites?

Layered structures made by cyanobacteria.

Which evolved first: prokaryotes or eukaryotes?

Prokaryotes.

What is a prokaryote?

A simple cell with no nucleus.

What is a eukaryote?

A cell with a nucleus.

What is the order of Earth's major eras?

Precambrian, Paleozoic, Mesozoic, Cenozoic.

About 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 first period of the Paleozoic?

Cambrian Period.

What was the Cambrian Explosion?

Many new types of animals appeared and quickly diversified.

Where did most Paleozoic life live?

In the oceans.

How did hard body parts help animals?

They provided protection and helped animals survive.

What continents made up Gondwana?

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

What continents made up Laurasia?

North America, Europe, and northern Asia.

What happened during the Ordovician Period?

The first land plants evolved.

What covered much of North America during the Silurian?

Shallow seas.

What was the Devonian Period called?

The Age of Fishes.

What were the first vertebrates to live on land?

Amphibians.

When did the coal swamps form?

During the Carboniferous Period.

What formed from ancient Carboniferous swamps?

Large deposits of coal.

What important animals evolved during the Carboniferous?

The first reptiles.

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 often called?

The Age of Reptiles.

What group do dinosaurs technically belong to?

Reptiles.

What was Earth's land like at the beginning of the Triassic?

Most land was joined in Pangaea.

When did Pangaea begin to break apart?

During the Triassic Period.

What major tectonic event happened about 200 million years ago?

Pangaea began breaking apart.

What plants became common during the Triassic?

Gymnosperms.

When did the first mammals appear?

Late in the Triassic Period.

What happened to Pangaea during the Jurassic?

It continued to split apart.

What were ichthyosaurs and plesiosaurs?

Large marine reptiles.

What animal links dinosaurs and birds?

Archaeopteryx.

What was Archaeopteryx?

An animal with both reptile and bird features.

Did all dinosaurs grow very large?

No.

What plants evolved during the Cretaceous?

Angiosperms, or flowering plants.

What happened at the end of the Cretaceous?

A mass extinction killed the dinosaurs and many other species.

What most likely caused the extinction of the dinosaurs?

A large meteorite or asteroid impact.

Where did the dinosaur-killing meteorite strike?

Near the Gulf of Mexico.

How could a meteorite impact cause a mass extinction?

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

What is the Cenozoic Era often called?

The Age of Mammals.

What became the dominant land animals during the Cenozoic?

Mammals.

How are mammals different from reptiles?

Mammals are warm-blooded and have hair or fur.

Are reptiles warm-blooded or cold-blooded?

Cold-blooded.

Why can mammals live more active lives than reptiles?

They can maintain a steady internal body temperature.

What generally causes mountain building?

Plate tectonics and colliding plates.

What major mountain ranges formed during the Cenozoic?

The Rockies, Alps, and Himalayas.

What happened to grasses during the Tertiary?

They spread rapidly across plains.

What current geologic period are we in?

The Quaternary Period.

What current geologic era are we in?

The Cenozoic Era.

What current geologic eon are we in?

The Phanerozoic Eon.

What are Milankovitch cycles?

Changes in Earth's orbit and tilt.

What can Milankovitch cycles help explain?

Ice ages.

What happened many times during the Quaternary?

Large continental glaciers advanced and retreated.

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

They became extinct.

What are two possible causes of large mammal extinctions after the last ice age?

Climate change and human hunting.