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Figure 5-1Page 92

CHAPTER 5: EVOLUTION AND BIODIVERSITY: ORIGINS, NICHES AND ADAPTATION

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Figure 5-2Page 93

Formationof the

earth’searly

crust andatmosphere

Small organic

moleculesform in

the seas

Large organic

molecules(biopolymers)

form inthe seas

First protocells

form inthe seas

Single-cellprokaryotes

form inthe seas

Single-celleukaryotes

form inthe seas

Variety ofmulticellularorganismsform, first

in the seas and lateron land

Chemical Evolution(1 billion years)

Biological Evolution(3.7 billion years)

© 2004 Brooks/Cole – Thomson Learning

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Click to view animation.

Animation

Stanley Miller's experiment animation.

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Plants begininvadingland

Evolution and expansion of life

First fossilrecord ofanimals

Plants invade the land

Age of reptiles

Age of mammals

Insects and amphibians invade the land

Modern humans(Homo sapiens)appear about2 secondsbefore midnight

Recorded humanhistory begins1/4 secondbefore midnight

Origin of life(3.6–3.8 billionyears ago)

Figure 5-3Page 94

noon

midnight

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Figure 5-4Page 96

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Click to view animation.

Example of directional selection animation.

Animation

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Figure 4-5Page 68

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Directional Natural Selection

Natural selection

New average Previous average

Num

ber o

f ind

ivid

uals

Coloration of snails

Proportion of light-coloredsnails in population increases

Num

ber o

f ind

ivid

uals Snail coloration

best adaptedto conditions

Average

Coloration of snails

Average shifts

Figure 5-5 (1)Page 97

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Popu

latio

n Si

ze

Low High Temperature

Zone ofintolerance

Zone ofphysiological stress

Optimum range Zone ofphysiological stress

Zone ofintolerance

Noorganisms

Feworganisms

Lower limitof tolerance

Abundance of organismsFew

organismsNo

organisms

Upper limitof tolerance

Figure 4-13Page 72

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Stabilizing Natural Selection

Coloration of snails

Light snailseliminated

Dark snailseliminated

Num

ber o

f ind

ivid

uals

Coloration of snails

Snails withextreme

coloration areeliminated

Num

ber o

f ind

ivid

uals

Average remains the same,but the number of individuals withintermediate coloration increases

Natural selection

Figure 5-5 (2)Page 97

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Number of individuals with light and dark coloration

increases, and the number with intermediate coloration decreases

Coloration of snails

Num

ber o

f ind

ivid

uals Snails with light and dark

colors dominate

Diversifying Natural Selection

Coloration of snails

Num

ber o

f ind

ivid

uals

Light colorationis favored

Darkcolorationis favored

Intermediate-colored snails are selected against

Natural selection

Figure 5-5 (3)Page 97

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Region of niche overlap

Generalist specieswith a broad nicheGeneralist species

with a narrow niche Nichebreadth

Nicheseparation

Num

ber o

f ind

ivid

uals

Resource use

Figure 5-6Page 98

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Figure 5-7Page 100

Black skimmerseizes small fishat water surface

Flamingofeeds on minuteorganismsin mud

Scaup and otherdiving ducks feed onmollusks, crustaceans,and aquatic vegetation

Brown pelican dives for fish,which it locates from the air

Avocet sweeps bill throughmud and surface water in search of small crustaceans,insects, and seeds

Louisiana heron wades intowater to seize small fish

Oystercatcher feeds onclams, mussels, and other shellfish into which it pries its narrow beak

Dowitcher probes deeplyinto mud in search ofsnails, marine worms,and small crustaceans

Knot (a sandpiper) picks upworms and small crustaceansleft by receding tide

Herring gull is atireless scavenger

Ruddy turnstone searchesunder shells and pebbles for small invertebrates

Piping plover feedson insects and tinycrustaceans on sandy beaches

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Stepped ArtFigure 5-8Page 100

Early foxpopulation

Spreadsnorthwardandsouthwardandseparates

Adapted to heatthrough lightweightfur and long ears, legs, and nose, whichgive off more heat.

Adapted to coldthrough heavierfur, short ears,short legs, shortnose. White furmatches snowfor camouflage.

Gray Fox

Arctic Fox

Different environmentalconditions lead to differentselective pressures and evolutioninto two different species.

Southern population

Northern population

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EURASIA

AFRICA

SOUTHAMERICA

INDIA

135 million years ago

Present65 million years ago

225 million years ago

120°80° 0°

120°120°

120°

80°80° 80°80°40°

40°120° 120°

120°

GONDWANALANDGONDWANALAND

120°

LAURASIALAURASIA

PANG

AEA

PANG

AEA

ANTARCTICAANTARCTICAAUSTRALIAAUSTRALIA

NORTH AMERICANORTH AMERICA

MADA-GASCARMADA-

GASCAR

Figure 5-9Page 101

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Animation

Click to view animation.

Stabilizing selection animation.

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Animation

Click to view animation.

Disruptive selection animation.

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Animation

Click to view animation.

Evolutionary tree of life animation.

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Animation

Click to view animation.

Evolutionary tree diagrams interaction.