How old?
In order
Emergence
Bye-Bye
Tough Stuff
100

Which law states that sedimentary rock layers are laid down on top of each other, making the bottom layer the oldest and the top layer the youngest?

Law of Superposition

100

Earth is approximately how old?

4.6 billion years old

100

When did the earliest life form appear?

3.8 billions years ago

100

What is a mass extinction?

The loss or death of many different species in a short period of time.

100

The preserved remains of a once living organism.

What is a fossil?

200

What is the science of determining the age of rock layers and/or fossils within the rock layers?

Relative dating or age dating

200

How many eons are there and what are their names?

4: Hadean, Archean, Proterozoic, & Phanerozoic 

200

What was the last life form to appear on Earth?

Humans

200

Mass extinction that occurred in the "late" part of 359 mya. It killed 75% of all species.

Late Devonian

200

What types of rock are fossils found in?

Sedimentary 

300

States that an igneous rock through the layer is younger that the layer it cuts through

Intrusive relationship

300

What was the first life form on Earth?

Anaerobic Microbes

300

When did the first mammals appear?

160 mya

300

Killed off the dinosaurs 65 mya by an asteroid or comet.

Cretaceous-Tertiary

300

What fossils is the impression of a once living organism?

Mold Fossil

400

This states that sediment is deposited horizontally or in "flat rows"

Principle of Original Horizontality  

400

Oxygen was poisonous to the anaerobic microbes, causing mass extinction. What was this called?

The Great Oxygenation

400

What life form introduced oxygen to the atmosphere?

Cyanobacteria

400

Occurred 248 mya that killed off 96% of species. Known as "The Great Dying"

Permian

400

A fossil that helps scientist date unknown or less studied fossils.

Index fossil

500

This states that a fault or fracture through rock layers must be younger than the layer it cuts through.

Cross cutting relationship

500

Comets are water-rich objects. It is believed they provided water to Earth, forming Earth's oceans throught (blank).

The Heavy Bombardment

500

When did the first multi cellular organisms appear and what did the have in common?

550 mya and they were invertebrates 

500

The first mass extinction that happened 443 mya killing 85% of species in the ocean. 

Ordovician-Silurian

500

A fossils that forms when organic matter of a dead organism or part of it us replaced by minerals and turned to stone.

Petrified Fossil

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