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BIOLOGY
CONCEPTS & CONNECTIONS
Fourth Edition
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
CHAPTER 15
Tracing Evolutionary History
Modules 15.1 – 15.5
From PowerPoint® Lectures for Biology: Concepts & Connections
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Are Birds Really Dinosaurs with Feathers?
• Did birds evolve from dinosaurs?
• Evolutionary biologists investigate this question
by looking at the fossil record
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• The fossil of the earliest
known bird,
Archeaopteryx,
was discovered in 1861
• Fossils of
dinosaurs with
feathers may
support the birddinosaur theory
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
EARTH HISTORY AND MACROEVOLUTION
15.1 The fossil record chronicles macroevolution
• Macroevolution consists of the major changes
in the history of life
– The fossil record chronicles these changes,
which have helped to devise the geologic time
scale
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Figure 15.1
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15.2 The actual ages of rocks and fossils mark
geologic time
• The sequence of fossils in rock strata indicates
the relative ages of different species
• Radiometric dating can gauge the actual ages of
fossils
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
15.3 Continental drift has played a major role in
macroevolution
• Continental drift is the slow, incessant
movement of Earth’s crustal plates on the hot
mantle
Eurasian
Plate
North
American
Plate
African
Plate
Pacific
Plate
Nazca
Plate
South
American
Plate
Split
developing
Indo-Australian
Plate
Antarctic Plate
Edge of one plate being pushed over edge of
neighboring plate (zones of violent geologic events)
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Figure 15.3A
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
India
South
America
MESOZOIC
Antarctica
PALEOZOIC
– Separation of
continents caused the
isolation and
diversification of
organisms
Eurasia
Africa
Millions of years ago
– Continental mergers
triggered extinctions
CENOZOIC
• This movement has
influenced the distribution
of organisms and greatly
affected the history of life
Laurasia
Figure 15.3B
• Continental drift explains the distribution of
lungfishes
– Lungfishes evolved when Pangaea was intact
Figure 15.3C
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NORTH
AMERICA
ASIA
EUROPE
AFRICA
SOUTH
AMERICA
AUSTRALIA
= Living lungfishes
= Fossilized lungfishes
Figure 15.3D
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15.4 Connection: Tectonic trauma imperils local
life
• Plate tectonics, the movements of Earth’s
crustal plates, are also associated with
volcanoes and earthquakes
– California’s
San Andreas
fault is a
boundary
between two
crustal plates
San Andreas fault
San Francisco
Santa Cruz
Los Angeles
Figure 15.4A
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• By forming new islands, volcanoes can create
opportunities for organisms
– Example: Galápagos
• But volcanic activity can also destroy life
– Example: Krakatau
Figure 15.4B, C
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15.5 Mass extinctions were followed by
diversification of life-forms
• At the end of the Cretaceous period, many lifeforms disappeared, including the dinosaurs
– These mass extinctions may have been a result of
an asteroid impact or volcanic activity
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?
Cretaceous
extinctions
90 million years ago
80
70
65
60
Figure 15.5
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• Every mass extinction reduced the diversity of
life
– But each was followed by a rebound in diversity
– Mammals filled the void left by the dinosaurs
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings