Name
Date
Class
Key Concept Builder
LESSON 3
The Mesozoic Era
Key Concept What major geologic events occurred during the Mesozoic era?
Pangaea
Laurasia
Gondwanaland
(northern Mesozoic continent)
(southern Mesozoic continent)
• North America
• Asia
• Europe
• Africa
• Australia
• Antarctica
• South America
Directions: Use the diagram to respond to the statement.
1. Describe the dominant geologic event of the Mesozoic era.
2. How did the climate of the Mesozoic era compare with that of the Paleozoic era?
3. What was the effect of the return of shallow seas during the Mesozoic era?
52
Geologic Time
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Directions: Answer each question on the lines provided.
Name
Date
Key Concept Builder
Class
LESSON 3
The Mesozoic Era
Key Concept What major geologic events occurred during the Mesozoic era?
Directions: Complete this cause-and-effect chart by writing a main effect of each event in the space provided.
Event
What Happened
1. Pangaea begins to break
apart.
2. No water is held by
glaciers or in ice caps.
3. Sea level rises.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
4. Water flows onto
continents as Pangaea
splits apart.
5. Narrow channels grow as
Pangaea continues to
split apart.
6. Sea level continues to
rise.
7. Sea levels rise and recede
along North America’s
eastern coastline.
8. The North American
continent slowly and
steadily moves westward.
9. A collision of plates
occurs along the western
coast of North America.
Geologic Time
53
Name
Date
Class
Key Concept Builder
LESSON 3
The Mesozoic Era
Key Concept What does fossil evidence reveal about the Mesozoic era?
Directions: Answer each question in the space provided.
Mesozoic Era Life According to Rock and Fossil Data
Plants
1. Which types of plants began
to appear?
Reptiles
4. Which dominant reptile lived on land?
5. Which present-day reptile shares an ancestor with dinosaurs
of the Mesozoic era?
6. What is significantly different between present-day reptiles
and Mesozoic reptiles?
Mammals
8. What was significant about how dinosaurs walked?
9. Which present-day animal are dinosaurs most closely linked
to?
3. What size were most
mammals?
10. In what other environment did reptiles live?
11. Besides being able to walk and swim, what else could some
dinosaurs do?
12. What happened to life on Earth about 65.5 mya?
54
Geologic Time
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
2. During which part of the
Mesozoic era did mammals
first evolve?
7. What was significant about how dinosaur legs were
positioned?
Name
Date
Class
Key Concept Builder
LESSON 3
The Mesozoic Era
Key Concept What does fossil evidence reveal about the Mesozoic era?
Directions: On the line before each statement, write T if the statement is true or F if the statement is false.
1. The Mesozoic era began 65.5 mya.
2. Three periods form the Mesozoic era, including the Triassic, the Jurassic, and
the Cretaceous.
3. The rising of sea levels made the evolution of new organisms difficult.
4. Organisms during the Mesozoic era adapted to cool environments.
5. Flowering plants appeared toward the end of the Cretaceous period.
6. The dominant reptiles on Earth were crocodiles.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
7. Scientists have discovered more than 300 species of dinosaurs.
8. One difference between dinosaurs and present-day reptiles is the dinosaur’s
unique hip structure.
9. Scientists who study dinosaurs think they are more closely related to mammals
than to present-day reptiles.
10. The dinosaur Archaeopteryx had wings and fur.
11. Plesiosaurs were marine reptiles that had small heads and long necks.
12. One pterosaur, the Quetzalcoatlus, had neck length of nearly 12 m.
13. A mass extinction occurred about 65.5 mya.
14. Scientists hypothesize that the Cretaceous extinction event occurred following
the impact of a large meteorite.
15. Large amounts of dust in the oceans cause plants to die.
16. Many animals died before their species adapted to changes in the environment.
Geologic Time
55