Definitions
Geologic Time Scale
Grab Bag
Divisions of Geologic Time
Fossils
100
_________ is the death of every member of a species
What is extinction?
100

Name the time in Earth's history: Clue #1: 4.6 billion to 542 million years ago Clue #2: no Oxygen in air

What is Precambrian?

100
True/False: Humans have existed for most of Earth’s history.
False.
100
The largest division of geologic time are ______________.
What are eons?
100
How did scientists know what dinosaurs looked like?
They examine fossil evidence.
200

___________ is word to describe layers of rocks

What is rock strata?

200
Name the time in Earth's history: Clue #1: 251 million years ago Clue #2: Age of Reptiles
What is the Mesozoic era?
200
How is the geologic time scale of Earth’s history divided?
by major events or changes.
200
Eons are divided into __________.
What are eras?
200
The earliest fossils are of …
One-celled organisms
300
The age of an event or object in relation to other events or objects is called ______________
What is Relative age
300
Name the time in Earth's history: Clue #1: 65 million years ago to today Clue #2: fossils are in the top layer
What is the 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 __________.
What are periods?
300
A fossil is an object that contains traces, remains, or evidence of ..
Living things from long ago
400
The oldest sections are shown on the __________, and the recent sections would be on the ________.
What is bottom/top?
400

Name the time in Earth's history: Clue #1: Humans first appeared

What is the Cenozoic?

400

What causes and extinction?

change in environment, natural disasters, or disease

400

Earths history can be compared to a....

What are chapter books?

400
A well-known fossil group of extinct marine creatures that first appeared in the early Cambrian period.
What is the trilobite?
500

This event separated the early Precambrian and the Late Precambrian

What is the evolution of life?

500
The first trace of life on earth can be traced back to..
3.8 billion years ago.
500
Give an example of creatures that were victims of a mass extinction
What are dinosaurs?
500

There are _____ eras in Earth’s history.

What is six?

500
The soft parts of an organism often decay very quickly. The result is that many fossils..
Only preserve traces of the hard parts of the organism.
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