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Visualizing Geologic Time

Introduction:  The purpose of this lab is to begin to visualize the immensity of geologic time on Earth.  An additional objective is to learn the standard geologic time scale.  To accomplish these goals, you will construct a scale model of the geologic time scale using the attached time scale as a guide. 

Directions:

1)      Cut a 3 meter (300 cm) long piece of adding machine tape.  This length of tape will represent 4,600,000,000 years of geologic time.

 

2)      Using ratios, determine the positions of the following boundaries on the tape.  Draw a vertical line (using a ruler) at each boundary and label it neatly.

Eon

Era

Period

Age (m.y.a)

Phanerozoic

Cenozoic

Quaternary

 

 

Tertiary

65

Mesozoic

Cretaceous

 

Jurassic

 

Triassic

 

Paleozoic

Permian

 

Pennsylvanian

 

Mississippian

 

Devonian

 

Silurian

 

Ordovician

 

Cambrian

540

Precambrian (or Cryptozoic)

Proterozoic

 

 

Archean

 

Hadean

 

4600

 

      3)  Mark the following events on your geologic time scale.  Using clipart, place a representative picture for each event in the appropriate location.

            a) Age of meteorites 4,600,000,000 billion years.

            b) First prokaryotic cells (no nucleus) 3,500,000,000 years ago

            c) First eukaryotic cells (nucleus) 1,750,000,000 years ago

            d) First abundant invertebrate fossils - 540,000,000 years ago

            e) First land plants 430,000,000 years ago

            f) First amphibians 400,000,000 years ago

            g) First reptiles 300,000,000 years ago

            h) First dinosaurs and primitive mammals 250,000,000 years ago

            i) First birds 200,000,000 years ago

j) Extinction of dinosaurs and rapid development of mammals 65,000,000 years ago

k) First homonids 6,500,000 years ago

 

4)      Answer the following questions:

 

A)    What do the Era divisions represent?

 

 

B)    What do the Period divisions represent?

 

 

C)    What percentage of geologic time did dinosaurs roam?

 

 

D)    What percentage of geologic time have homonids existed?

 

 

E)     What percentage of geologic time dies the Precambrian represent?

 

 

F)     Why do you think the Phanerozoic is divided into many periods whereas the Precambrian is not?

 

 

G)    Why do  you think the Precambrian is also called the Cryptozoic?

 

 

5) Come up with an acronym that will help you memorize the Eras from most recent to oldest.

 

 

6) Come up with an acronym that will help you memorize the Periods from most recent to oldest.