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Definitions
Geologic Time Scale
Grab Bag
Divisions of Geologic Time
Fossils
100

_________ is the death of every member of a species

extinction

100

Name the time in Earth's history:  Eon: no Oxygen in air and no fossils were found.

Hadean Eon

100
True/False: Humans have existed for most of Earth’s history.
False.
100

The largest division of geologic time are ______________.

eons

100
How did scientists know what dinosaurs looked like?
They examine fossil evidence.
200

___________ is the extinction of many species at the same time

mass extinction

200

Name the time in Earth's history: Era: Clue #1: 251 million years ago Clue #2: Age of Reptiles

Mesozoic era

200
How is the geologic time scale of Earth’s history divided?
by major events or changes.
200

Eons are divided into __________.

eras

200
The earliest fossils are of …
One-celled organisms
300

This event happened during the Mesozoic era.

Ice Age

300

Name the time in Earth's history: Era

Rise of mammals, and the climate warmed up after KPG

Cenozoic era

300
True/False: Throughout Earth’s history, the number and type of life forms has remained fairly constant.
False.
300

Eras are divided into __________.

periods

300
A fossil is an object that contains traces, remains, or evidence of ..
Living things from long ago
400

Most severe extinction in our planet's history.

The Great Dying

400

recent geological Epoch

Holocene

400

Mass extinction can happen when ..

Gradual changes in the climate or ocean currents OR huge events like a meteor falls from the sky and makes giant hole in the ground, kicking up dirt and soil into the air that blocks out the sun for a long time until plants die. Then when a lot of plants die, animals that eat plants have no food, and they die too.

400

Periods are divided into ____________.

epochs

400

A well-known fossil group of extinct marine creatures that first appeared in the early Cambrian period.

trilobite

500

This event was the relatively rapid growth of diversity and complexity of the ocean. This bang started the Paleozoic Era. 

Cambrian Explosion

500

This Eon means "earlier life" and also the scientists found the appearance of Eukaryotes. 

Proterozoic Eon

500

Give an example of creatures that were victims of a mass extinction

dinosaurs

500

There are _____ eons in Earth’s history.

four

500

There are traces of fossils during Hadeon Eon?

True or False?

False