descent with modification a darwinian view of life n.
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Descent with Modification: A Darwinian View of Life. Chapter 22. Figure 22.1 A marine iguana, well-suited to its rocky habitat in the Galápagos Islands. Marine iguana. Linnaeus (classification). Hutton (gradual geologic change). Lamarck (species can change). Malthus (population limits).

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Chapter 22


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figure 22 2 the historical context of darwin s life and ideas

Linnaeus (classification)

Hutton (gradual geologic change)

Lamarck (species can change)

Malthus (population limits)

Cuvier (fossils, extinction)

Lyell (modern geology)

Darwin (evolution, natural selection)

Mendel (inheritance)

Wallace (evolution, natural selection)

American Revolution

French Revolution

U.S. Civil War

1800

1850

1900

1750

1795

Hutton proposes his theory of gradualism.

1798

Malthus publishes “Essay on the Principle of Population.”

1809

Lamarck publishes his theory of evolution.

Lyell publishes Principles of Geology.

1830

Darwin travels around the world on HMS Beagle.

1831–1836

1837

Darwin begins his notebooks on the origin of species.

1844

Darwin writes his essay on the origin of species.

1858

Wallace sends his theory to Darwin.

TheOrigin of Species is published.

1859

1865

Mendel publishes inheritance papers.

Figure 22.2 The historical context of Darwin’s life and ideas
figure 22 5 the voyage of hms beagle

England

EUROPE

NORTH

AMERICA

ATLANTIC

OCEAN

PACIFIC

OCEAN

Galápagos

Islands

HMS Beagle in port

AFRICA

SOUTH

AMERICA

Darwin in 1840,

after his return

AUSTRALIA

Cape of

Good Hope

Andes

Tasmania

Cape Horn

New

Zealand

Tierra del Fuego

Figure 22.5 The voyage of HMS Beagle
figure 22 6 beak variation in gal pagos finches

(a) Cactus eater. The long,sharp beak of the cactusground finch (Geospizascandens) helps it tearand eat cactus flowersand pulp.

(c) Seed eater. The large groundfinch (Geospiza magnirostris)has a large beak adapted forcracking seeds that fall fromplants to the ground.

(b) Insect eater. The green warbler finch (Certhidea olivacea) uses itsnarrow, pointed beak to grasp insects.

Figure 22.6 Beak variation in Galápagos finches
figure 22 7 descent with modification

Sirenia

(Manatees

and relatives)

Loxodonta

cyclotis

(Africa)

Elephas

maximus

(Asia)

Loxodonta

africana

(Africa)

Hyracoidea

(Hyraxes)

Years ago

Stegodon

Mammut

Mammuthus

Deinotherium

Platybelodon

Millions of years ago

Barytherium

Moeritherium

Figure 22.7 Descent with modification
figure 22 10 artificial selection

Lateral

buds

Terminal

bud

Brussels sprouts

Cabbage

Flower

cluster

Leaves

Cauliflower

Kale

Stem

Flower

and

stems

Broccoli

Wild mustard

Kohlrabi

Figure 22.10 Artificial selection
figure 22 12 can predation pressure select for size and age at maturity in guppies

Reznick and Endler transplanted guppies from pike-cichlid pools to killifish pools

and measured the average age and size of guppies at maturity over an 11-year period (30 to

60 generations).

Pools with killifish,

but not guppies prior

to transplant

Experimental

transplant of

guppies

EXPERIMENT

Predator: Killifish; preys

mainly on small guppies

Guppies:

Larger at

sexual maturity

than those in

“pike-cichlid pools”

Predator: Pike-cichlid; preys mainly on large guppies

Guppies: Smaller at sexual maturity than

those in “killifish pools”

Figure 22.12 Can predation pressure select for size and age at maturity in guppies?
slide19

RESULTS

After 11 years, the average size and age at maturity of guppies in the transplanted

populations increased compared to those of guppies in control populations.

Control Population: Guppies

from pools with pike-cichlids

as predators

185.6

92.3

85.7

161.5

Weight of guppies

at maturity (mg)

Age of guppies

at maturity (days)

58.2

48.5

76.1

67.5

Experimental Population:

Guppies transplanted to

pools with killifish as

predators

Males

Females

Males

Females

CONCLUSION

Reznick and Endler concluded that the change in predator resulted in different variations

in the population (larger size and faster maturation) being favored. Over a relatively short time, this altered

selection pressure resulted in an observable evolutionary change in the experimental population.

figure 22 13 evolution of drug resistance in hiv

Patient

No. 1

Patient No. 2

Percent of HIV resistant to 3TC

Patient No. 3

Weeks

Figure 22.13 Evolution of drug resistance in HIV
figure 22 16 comparison of a protein found in diverse vertebrates

Percent of Amino Acids That Are

Identical to the Amino Acids in a

Human Hemoglobin Polypeptide

Species

100%

Human

Rhesus monkey

95%

Mouse

87%

Chicken

69%

Frog

54%

14%

Lamprey

Figure 22.16 Comparison of a protein found in diverse vertebrates
figure 22 17 different geographic regions different mammalian brands

NORTH

AMERICA

Sugar

glider

AUSTRALIA

Flying

squirrel

Figure 22.17 Different geographic regions, different mammalian “brands”