Geologic and Biologic Scaled Timeline
Integrated Science 2Name:Per:
Background
The Earth solidified 4.6 billion years ago. Life has been evolving on Earth for more than 3.5 billion years. These are time spans that are difficult to comprehend. Our limited experience with time involves years grouped into decades and centuries – not millions or thousands of millions otherwise known as a billion years! To understand geologic and biologic origins we can try to represent time concretely by converting time into a linear dimension with a scale that is more manageable. Scaled time lines can be used to represent changes in a more usable context. In this activity, you will construct a scale model of the major geologic and biologic events in Earth’s history. This will help give you a sense of when critical events happened in the history of life and of the earth.
Pre-Lab Questions
- On a timeline of the Earth’s history, put an “X” where you think the age of dinosaurs would first appear.
Earth Formed / Present Day
- On a timeline of the Earth’s history, put an “X” where you think humans would first appear.
Earth Formed / Present Day
- On a timeline of Earth’s history, put an “X” where you think the continents formed.
Earth Formed / Present Day
Procedures
Remember:109 = 1,000,000,000 / one billion
106 = 1,000,000 / one million
105 = 100,000 / one hundred thousand
104 = 10,000 / ten thousand
- Review the data table that accompanies this activity. You will notice that the “Distancein Classroom(feet)” column is blank. This must be filled in before you can begin creating your scaled model.
- You will create a model of some of the important biological and geological milestones using the center aisle of the classroom as the timeline.
a.) Your model will be 30feet down the length of the classroom. One tile on the floor is one foot long. Therefore, because there are 4.6 billion years of earth history and 30 tiles, every foot of space on your timeline is equal to 153 million years (4,600,000,000 years ÷30 tiles = 153,000,000 years per tile).
b.) To begin, you must convert the data found in the “Approximate Age” column to a unit of distance. The formula for this conversion is as follows:
c.) When you have finished filling in the Data Table, you will be assigned one of the events to measure and tape to the floor timeline.
- Complete the Analysis Questions on page 3.
Example: the third conversion on the Geologic Time Scale (first Single-celled organism) requires you to convert 4000 million years to distance. Using the formula above the conversion would look like this:
therefore, you would tie the flag 27.8 feet from the beginning where the first single-celled organisms appeared.
Data Table
Event / Approximate Age / Distance in Class (ft)A / Formation of the Earth / 4600 million years
B / Oldest known rock / 4300 million years
C / First single-celled organism / 4000 million years
D / Age of most continental crust / 3700 million years
E / First viruses appear / 3500 million years
F / Blue-green algae
(First oxygen-producers) / 3000 million years
G / First fungi appear / 1000 million years
H / First multi-celled organism / 700 million years
I / Precambrian Extinction
(70% of all life wiped out) / 650 million years
J / First shellfish appear / 570 million years
K / First fish appear / 510 million years
L / First true plants appear / 498 million years
M / First sharks appear / 390 million years
N / First amphibian appear / 375 million years
O / First reptile appears / 325 million years
P / Permian-Triassic Extinction
(99% of all life wiped out) / 250 million years
Q / Mesozoic Era begins
(Age of the dinosaurs) / 245 million years
R / First mammal appears / 200 million years
S / Age of most oceanic crust / 180 million years
T / First known bird appears / 160 million years
U / Rocky Mountains formed / 80 million years
V / Extinction of the dinosaurs / 65 million years
W / First proto-humans appear / 3.5 million years
X / Earliest modern humans appear / 2 million years
Y / Last Ice Age / 0.02 million years
Z / Recorded human history begins / 0.01 million years
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Scaled Time Line
Analysis Questions
1.Revisit your pre-lab questions. How close were you to predicting the timing of each events? Which one were you closest to?
2.Which of these event’s position on the timeline was the most surprising to you? Why? (what preconceived notions did you have about this event?)
3.How many events involving living organisms are in the first half of earth’s history?
How many events involving living organisms are in the second half of earth’s history?
4.How long did dinosaurs exist on earth?
How long have humans (including proto-humans) lived on earth?
5.Using your data table, create a timeline of organism evolution from single-celled organisms to modern humans by listing them in order of appearance on earth.
- Which organisms would have gone extinct at the Permian-Triassic extinction 250 million years ago?
- For how many billions of years, did earth exist with nothing more sophisticated than single-celled organisms?
What percent of earth’s history is this? (divide your answer by 4.6 and multiply by 100).
Formation of the Earth4.6 Billion Years Ago
Oldest Known Rock
4.3 Billion Years Ago
First Single-Celled Organism
4 Billion Years Ago
Age of Most Continental Crust
3.7 Billion Years
First Viruses Appear
3.5 Billion Years Ago
Blue-Green Algae
(First oxygen-producers)
3 Billion Years Ago
First Fungi Appear
1 Billion Years Ago
First Multi-Celled Organisms
700 Million Years Ago
Precambrian Extinction
(70% of all life wiped out)
650 Million Years Ago
First Shellfish Appear
570 Million Years Ago
First Fish Appear
510 Million Years Ago
First True Plants Appear
498 Million Years Ago
First Sharks Appear
390 Million Years Ago
First Amphibian Appears
375 Million Years Ago
First Reptile Appears
325 Million Years Ago
Permian-Triassic Extinction (99% of all life wiped out)
250 Million Years Ago
Mesozoic Era Begins
(The Age of the Dinsaurs)
245 Million Years Ago
First Mammal Appears
200 Million Years Ago
Age of Most Oceanic Crust
180 Million Years
First Known Bird Appears
160 Million Years Ago
Rocky Mountains Formed
80 Million Years Ago
Extinction of the Dinosaurs
65 Million Years Ago
First Proto-Humans Appear
3.5 Million Years Ago
Earliest Modern Humans Appear
2 Million Years Ago
Last Ice Age
20 Thousand Years Ago
Recorded Human History Beings
10 Thousand Years Ago
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Scaled Time Line