Geologic Time Lab
Background:
The Earth has changed dramatically and repeatedly over a history that spans nearly 4.6
billion years. Such immense spans of time are difficult for most of us to comprehend.
They fall outside our range of human experience. Compared to the span of the earth’s
history, a human lifetime is very short. This makes it very difficult for any person to get a
clear picture of the vast periods of time involved in geological history. However, some
idea of these time spans is necessary to understand the slowness of the processes that
change the earth and the life on it. The procedures you will follow in this investigation
will help you to make your discovery of the real meaning of geologic time.
Objective:
In this activity, you will use a long paper strip and a reasonable scale to represent
virtually all of geologic time on Earth, including significant events in the development of
life on earth as well as recent human events.
Materials:
5 meters of receipt tape
Meter stick
Metric ruler
Markers or colored pencils etc
Procedure:
1. Measure out 5 meters of receipt paper and spread it out on the floor. Use tape to
hold it down.
2. Use the following time scale:
1 meter = 1 billion years
10 centimeters = 100 million years
1 centimeter = 10 million years
1 millimeter = 1 million years
3. At the end of the tape draw a line and label it “present.”
4. Measure to find the spot on the paper where 4.6 billion years ago would be and label
this “Earth’s Beginning.”
Ask yourself, 4.6 billion years is ____ meters and ____cm away from the present.
5. Please note that our timeline is broken into many time frames and are distinguished
by Eras, Periods and Epochs. Calculate the length required for each. Then label them
on your timeline.
Era or Period
Million Years Ago
(mya)
Cenozoic Era
Mesozoic Era
Paleozoic Era
Precambrian
Quaternary Period
Neogene Period
Paleogene Period
Cretaceous Period
Jurassic Period
Triassic Period
Permian Period
Carboniferous Period
Devonian Period
Silurian Period
Ordovician Period
Cambrian Period
66 mya
251 mya
542 mya
4600 mya
1.6 mya
23 mya
66 mya
146 mya
200 mya
251 mya
299 mya
359 mya
416 mya
444 mya
488 mya
542 mya
Length
(label m, cm or mm)
6. Shade each PERIOD (there are 12) lightly with a different color.
Do not color too brightly because you will be adding words/pictures in the next step.
6. Use the following table to add a picture and/or word(s) to your timeline of
Important Events in Earth’s History. Numbers 20-28 will not be able to be added to your
timeline. Why? _____________________________________________________
Some Important Events in Earth’s History
Event
#
Date in years
before present
1
2
3
4
5
4.6 billion
4.4 billion
4.1 billion
3.9 billion
3.8 billion
Earth forms
Oldest mineral grain found
Oldest piece of rock ever found
Oldest evidence of a continent
First evidence of life
6
3.5 billion
First fossils (algae and bacteria)
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
1.8 billion
1.1 billion
540 million
460 million
440 million
410 million
250 million
247 million
240 million
220 million
145 million
65 million
30 million
5 million
1.8 million
40,000
13,000
24
10,000
End of last Ice Age
25
26
27
28
8,000
2,000
500
~46
Founding of Jericho, the first known city
Roman domination of the world
European rediscovery of the Americas
Humans first explore the moon
Event
Free oxygen in atmosphere
First fossil of a complex organism (a worm)
First abundant life found in the rock record
First fish
First land plants
First land animals
Largest mass extinction occurs
First dinosaurs
First mammals
Breakup of super-continent Pangaea begins
First flowering plants
Dinosaurs and other animals go extinct
Mammals/flowering plants become abundant
Beginning of Cascade Volcanic Arc
First primate in genus Homo
First Homo sapiens
Humans first inhabit North America
Questions:
1) There are many theories that explain the extinction of dinosaurs. One of them
includes a massive meteorite that struck the earth which such an enormous force that it
created a “nuclear winter.” This nuclear winter would result in a dust cloud so huge that
light could not pass through it. This would stop photosynthesis, terminate the food supply
and cool the earth. Other results of the impact would be acid rain, tsunamis, wildfires
and a delayed greenhouse effect. If such a meteorite was to strike the Mexican
Yucatan peninsula as suggested by the iridium-enriched sediment in our rock records,
how many million years ago would that have occurred?
_________________________________________________________________________________
2) What percentage of the timeline falls in the Precambrian Era? _________________
_________________________________________________________________________________
3) What percentage of the Earth’s History has man been in existence? _____________
_________________________________________________________________________________
4) It is estimated that the Universe has been existence 15 billion year (15,000 million
years). What percentage of the Universe’s existence has the Earth been around? ______
_________________________________________________________________________________
5) Considering major events in the history of modern man, such as the signing of the
Declaration of Independence, the first man on the moon and the dropping of the
atomic bomb, why did this lab NOT ask you to label events like these on the timeline?
__________________________________________________________________________________