Name________________________________
Geologic Time Events Activity
The emergence of intelligent life on Earth occurred because a series of events played out favorably
for us to exist at this time. Many events occurred in the distant past that led the Earth and the life that
occupies it to be what it is today. To help visualize how long we have been here and how long ago these
events took place your group will scale the entire history of the Earth on a strip of paper.
Procedure:
1. Using the scale of 1 meter = 1 billion years (which is the same as 1 mm = 1 million years and 1cm = 10
million years) estimate how far away from the line marked “Today” the event should be placed.
Scaling Examples
Ex: event occurred 75 mya = 75mya/10 = 7.5 cm distance away from today
Ex: event occurred 3.5 bya = 3,500 mya/10 = 350 cm distance away from today
2. Obtain the correct answers for age of event from your teacher and then recalculate the scale for these
correct ages to be used on your geologic time lines.
Event
#
1
2
3
Geologic Event
Rocky Mountains
are formed
First known fish
Earliest humans
4
Formation of
Appalachian Mts.
5
First known
mammals appear
6
First single-celled
organism
7
Great lakes
formed
8
Oldest rock
formed
9
Extinction of the
dinosaurs
10
First known Land
plant
11
First known reptile
12
First multi-celled
organism
13
First known
amphibian
14
15
16
First known bird
First dinosaurs
appear
Glaciation of Ohio
17
Snow Ball Earth
Estimated Age
(in millions of
years)
Distance away
from “Today”
(in cm)
Correct Age of
Event
(in millions of
years)
Correct Distance
Away from “Today”
(in cm)
18
K/T mass
extinction
19
Triassic Jurassic
Mass Extinction
20
Ordovician/Silurian
mass Extinction
21
Late Devonian
mass Extinction
22
Permian Mass
Extinction