Name
Date
Key Concept Builder
Class
LESSON 1: Use purple text pages 363-367
Geologic History
Key Concept How was the geologic time scale developed?
Directions: On each line, write the term from the word bank that correctly completes each sentence. Each term
is used only once.
epochs
eras
fossils
Mesozoic
Paleozoic
Periods
Phanerozoic
Triassic
1. Divisions in the geologic time scale
were developed based on differences
in the
in different rock layers.
2. Eons, the longest unit of geologic time,
are subdivided into
.
3. Periods are subdivided into
.
4. Jurassic and the Ordovician are examples
of geologic
.
5. The Cretaceous period is part of the
era.
6. The Cambrian period is part of the
era.
7. The Mesozoic era includes the
period.
8. The
eon
includes the Quaternary period.
16
Geologic Time
Name
Date
Key Concept Builder
Class
LESSON 2: Use purple text pgs371-375
The Paleozoic Era
Key Concept What major geologic events occurred during the Paleozoic era?
Directions: Answer each question on the lines provided
Early Paleozoic
1. Which age is this time known as?
2. What was the climate like?
3. What happened to the seas during this time?
4. What two things resulted from this change in sea level?
5. Where was North America located?
6. Where did animal life exist?
7. Which type of animals existed?
Middle Paleozoic
8. Which age is this time known as?
9. What happened between moving continents?
10. What was created from this movement?
11. Which type of animals further evolved in the seas?
12. Which type of animals evolved on land?
Late Paleozoic
13. Which age is this time known as?
14. What was the climate like near the end of this time?
15. What landmass formed during this time?
16. Which type of animals evolved on land toward the end of this time?
17. What happened to 70 percent of all life-forms on land at the end of this time?
34
Geologic Time
Name
Key Concept Builder
Date
Class
LESSON 2: Use purple text pgs371-375
The Paleozoic Era
Key Concept What does fossil evidence reveal about the Paleozoic era?
Directions: Put a check mark in the space that correctly identifies what rock and fossil evidence reveal about
the Paleozoic era.
When It Happened
What Happened
Early
Paleozoic
Middle
Paleozoic
Late
Paleozoic
1. Seventy percent of all life-forms on land
become extinct.
2. All life is in the oceans.
3. It is the age of invertebrates.
4. Heavily armored fish evolve.
5. Reptiles evolve.
6. Cockroaches, dragonflies, and other insects
evolve on land.
7. Dense forests grow along shallow inland
seas.
8. It is the age of fishes.
9. New life-forms evolve along coral reefs.
10. It is the age of amphibians.
11. Ninety-five percent of marine life becomes
extinct.
12. The first plants appear.
13. Coal swamps form.
14. The largest mass extinction in Earth’s
history occurs.
36
Geologic Time
Name
Date
Content Practice A
Class
LESSON 3: Use purple text pages 379-383
The Mesozoic Era
251 mya
• Ocean water
flows onto
continents.
• Mesozoic era
begins.
• Pangaea begins
• Inland seas
to break apart.
form.
• Two continents
form—Late
Triassic.
• Flowering
plants appear.
• Dinosaurs
become the
dominant
reptile.
• Mammals
evolve.
65.5 mya
• A meteorite hits
Earth.
• Volcanoes erupt.
• A mass
extinction
occurs.
Directions: Use the diagram to answer each question.
1. How long ago did the Mesozoic era begin?
2. What happened to Pangaea?
3. What happened as the ocean waters rose higher?
4. Which life-forms evolved during the Mesozoic era?
5. Which reptile was dominant during the Mesozoic era?
6. Which event marks the end of the Mesozoic era?
7. What do scientists hypothesize led to the mass extinction?
Geologic Time
4