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BIOLOGY
CONCEPTS & CONNECTIONS
Fourth Edition
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
CHAPTER 13
How Populations Evolve
Modules 13.1 – 13.3
From PowerPoint® Lectures for Biology: Concepts & Connections
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Evolution
• Evolution is genetic change in a population
over time.
• Charles Darwin was the first scientist to
propose the theory of evolution, in 1859.
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EVIDENCE OF EVOLUTION
13.1 The Voyage of the Beagle
• Darwin was born in 1809.
• In 1831, he was on a boat that
was mapping coastlines, the
HMS Beagle.
• He studied plants and animals
on the Galapagos Islands.
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• Darwin observed:
– similarities between living and fossil organisms
– the diversity of life on the Galápagos Islands,
such as finches (birds) and giant tortoises
Figure 13.1A
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Darwin concluded that:
– The Earth was old and constantly changing (4.6
billion years old)
– Living things also change (evolve) over
generations.
– Living things are related to animals and plants
that used to exist but are now extinct.
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Evidence for Evolution
• Fossils
• Biogeography
• Comparative Anatomy
• Comparative Embryology
• Molecular Biology
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
13.2 Fossils
• Fossils are the preserved
remains of dead organisms.
• They show how life has
changed over time.
• Examples:
– Hominid skull: an early
relative
– Petrified trees: trees turned to
Figure 13.2A, B
stone
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– Ammonite casts: 375
million year old
aquatic organisms
– Fossilized organic
matter in a leaf:
molecular and
cellular structures
are preserved.
Figure 13.2C, D
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– Scorpion in amber:
30 million years old,
intact DNA
– “Ice Man”: 5,000
years old, cells and
DNA preserved.
Figure 13.2E, F
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• The fossil record shows that
organisms have appeared in a
historical sequence
• Many fossils link
early extinct species
with species living
today
– These fossilized
hind leg bones link
living whales with
their land-dwelling
ancestors
Figure 13.2G, H
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Biogeography
• Biogeography is the
geographic distribution
of species (where
animals live).
• Plants and animals in
different parts of the
world are related
because they share
common ancestors.
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Comparative Anatomy
• Anatomical
similarities among
many species show
signs of common
descent.
• Humans, cats, whales,
and bats have the
same skeletal
Human
elements because we
all evolved from a
common ancestor.
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Cat
Whale
Bat
Comparative Embryology
• Closely related
organisms often have
similar stages in their
embryonic
development.
• Fish, frogs, snakes,
birds, apes, and people
all have pharyngeal
slits as embryos which
develop into either gills
or lungs.
• We are all related!
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Molecular Biology
• Scientists can compare DNA sequences and
amino acid sequences between species to see
how closely related we are.
• Humans and chimps share 98.5% of their DNA.
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings