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Copyright © 2005 Pearson Prentice Hall, Inc.
Chapter 14 Principles of Evolution
• How Did Evolutionary Thought Evolve?
• Early Biological Thought Did Not Include the Concept of Evolution
• Exploration of New Lands: Staggering Diversity of Life
• Fossil Discoveries: Life Had Changed Over Time– The Grand Canyon of the Colorado River F14.1 – Types of fossils (F14.2 p. 266) – Fossils of extinct organisms (F14.3 p. 267)
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Copyright © 2005 Pearson Prentice Hall, Inc.
eggs in nest fossilized feces (coprolites)
bones footprints skin impression
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Copyright © 2005 Pearson Prentice Hall, Inc.
How Did Evolutionary Thought Evolve?
• Some Scientists Devised Nonevolutionary Explanations for Fossils
• A Few Scientists Speculated That Life Had Evolved
• Geology Provided Evidence That:– Earth Is Exceedingly Old– Gradual Change Over a Long Time Produces Large Differences
• Some Pre-Darwin Biologists Proposed Mechanisms for Evolution
• Darwin and Wallace Proposed a Mechanism of Evolution– Darwin’s finches, residents of the Galapagos Islands
(F14.4 p. 269)
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Copyright © 2005 Pearson Prentice Hall, Inc.
Copyright © 2005 Pearson Prentice Hall, Inc.
Large ground finch, beaksuited to large seeds
Small ground finch, beaksuited to small seeds
Warbler finch, beaksuited to insects
Vegetarian tree finch, beaksuited to leaves
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Relatively constant resourcesand population size over time
Potential forrapid reproduction
Competition for survivaland reproduction
Variability instructures and behaviors
NATURAL SELECTION:On the average, the fittest
organisms leave the most offspring
Some variabilityis inherited
EVOLUTION:The genetic makeup of the population
changes over time,driven by natural selection
Observation
Conclusion based on observation
How Does Natural Selection Work?
•A flowchart of evolutionary reasoning (F14.5 p. 272)
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14.2 How Does Natural Selection Work?
• 14.2.1 Modern Genetics Confirmed Darwin’s Assumption of Inheritance
• 14.2.2 Natural Selection Modifies Populations Over Time– Figure 14.6 The evolution of the
horse (p. 272)
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35
50
25
5
1
0
Merychippus
Hyracotherium
Mesohippus
Hipparion
AnchitheriumArchaeohippus
Pliohippus
Equus
Paleotheres
graz
ing
mill
ion
s o
f y
ear
s a
go
toothforefoot
brow
sing
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How Do We Know That EvolutionHas Occurred?
• Fossils Provide Evidence of Evolutionary Change Over Time
• Comparative Anatomy Gives Evidence of Descent with Modification– Homologous Structures Provide Evidence of
Common Ancestry (F14.7 p.
274) – Functionless, Vestigial Structures Inherited
from Ancestors (F14.8 p.
275)
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Pterodactyl
Bird
Bat
Dolphin
Seal
Dog
Sheep Shrew
humerus
ulna
metacarpalsphalanges
radiuscarpals
Human
GRASPINGRUNNINGSWIMMINGFLYING
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Salamander
Baleen whale
Boa constrictor
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How Do We Know That Evolution Has Occurred?
• Some Anatomical Similarities from Evolution in Similar Environments
•Analogous structures (F14.9 p. 276)
• Similar Embryonic Stages Suggest Common Ancestry (F14.10 p. 276)
• Biochemical and Genetic Analyses Reveal Relatedness Among Diverse Organisms
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Copyright © 2005 Pearson Prentice Hall, Inc.
Copyright © 2005 Pearson Prentice Hall, Inc.
What Is the Evidence That Populations Evolve by Natural
Selection?
• Artificial Selection Controlled Breeding Modifies Organisms (F14.11 p. 277)
• Evolution by Natural Selection Occurs Today– When Fewer Predators Are Present, Brighter
Coloration Can Evolve– Natural Selection Can Lead to Pesticide Resistance– Experiments Can Demonstrate Natural Selection– Selection Acts on Random Variation to Favor the
Traits That Work Best in Particular Environments
Copyright © 2005 Pearson Prentice Hall, Inc.
Copyright © 2005 Pearson Prentice Hall, Inc.
What Is the Evidence That Populations Evolve by
Natural Selection?• Evolution by Natural Selection Occurs Today
– When Fewer Predators Are Present, Brighter Coloration Can Evolve
– Natural Selection Can Lead to Pesticide Resistance
Activity 14.2– Experiments Can Demonstrate Natural Selection– Selection Acts on Random Variation to Favor the
Traits That Work Best in Particular Environments
