Transcript Figure 22.7 Descent with modification

Chapter 22
Descent with Modification: A Darwinian View of
Life
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• Descent with modification
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Figure 22.1 A marine iguana, well-suited to its rocky
habitat in the Galápagos Islands
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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.
1830 Lyell publishes Principles of Geology.
1831–1836 Darwin travels around the world on HMS Beagle.
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.
1859 The Origin of Species is published.
1865 Mendel publishes inheritance papers.
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Figure 22.3 Fossils from strata of sedimentary rock
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•Grand Canyon
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Figure 22.4 Acquired traits cannot be inherited
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Figure 22.5 The voyage of HMS Beagle
• Sea Lions
• Tortoise
England
EUROPE
NORTH
AMERICA
ATLANTIC
OCEAN
PACIFIC
OCEAN
Galápagos
Islands
Darwin in 1840,
after his return
AFRICA
HMS Beagle in port
SOUTH
AMERICA
Andes
AUSTRALIA
Cape of
Good Hope
Tasmania
Cape Horn
Tierra del Fuego
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New
Zealand
Figure 22.6 Beak variation in Galápagos finches
(a) Cactus eater. The long,
sharp beak of the cactus
ground finch (Geospiza
scandens) helps it tear
and eat cactus flowers
and pulp.
(c) Seed eater. The large ground
finch (Geospiza magnirostris)
has a large beak adapted for
cracking seeds that fall from
plants to the ground.
(b) Insect eater. The green warbler
finch (Certhidea olivacea) uses its
narrow, pointed beak to grasp insects.
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Figure 22.7 Descent with modification
Sirenia
Hyracoidea (Manatees
(Hyraxes) and relatives)
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Elephas Loxodonta Loxodonta
cyclotis
maximus africana
(Africa)
(Asia)
(Africa)
Figure 22.8 Overproduction of offspring
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Figure 22.9 Variation in a population
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Figure 22.10 Artificial selection
Terminal
bud
Lateral
buds
Brussels sprouts
Cabbage
Flower
cluster
Leaves
Cauliflower
Kale
Stem
Flower
and
stems
Broccoli
Wild mustard
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Kohlrabi
Figure 22.11 Camouflage as an example of
evolutionary adaptation
(a) A flower mantid
in Malaysia
(b) A stick mantid
in Africa
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Figure 22.12 Can predation pressure select for size
and age at maturity in guppies?
EXPERIMENT
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
Predator: Killifish; preys
mainly on small guppies
Experimental
transplant of
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”
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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.
185.6
161.5
85.7 92.3
48.5
58.2
Control Population: Guppies
from pools with pike-cichlids
as predators
67.5 76.1
Males
Females
Males
Females
Experimental Population:
Guppies transplanted to
pools with killifish as
predators
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.
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Figure 22.13 Evolution of drug resistance in HIV
Patient
No. 1
Patient No. 2
Patient No. 3
Weeks
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Figure 22.14 Mammalian forelimbs: Homologous
structures
Human
Cat
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Whale
Bat
Figure 22.15 Anatomical similarities in vertebrate embryos
Pharyngeal
pouches
Post-anal
tail
Chick embryo
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Human embryo
Figure 22.16 Comparison of a protein found in
diverse vertebrates
Species
Percent of Amino Acids That Are
Identical to the Amino Acids in a
Human Hemoglobin Polypeptide
100%
Human
Rhesus monkey
95%
Mouse
87%
Chicken
69%
Frog
Lamprey
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54%
14%
Figure 22.17 Different geographic regions,
different mammalian “brands”
NORTH
AMERICA
Sugar
glider
AUSTRALIA
Flying
squirrel
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Figure 22.18 A transitional fossil linking past and
present
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