5. 1809
1798
1812
1795
1830
1790
1809 1831−36
1844
1859
1870
Lamarck publishes his
hypothesis of evolution.
Malthus publishes
“Essay on the Principle
of Population.”
Hutton proposes
his principle of
gradualism.
Charles Darwin
is born.
Darwin travels around
the world on HMS
Beagle.
The Galápagos Islands
Darwin writes his
essay on descent
with modification.
On the Origin of
Species is published.
While studying species
in the Malay Archipelago,
Wallace sends Darwin
his hypothesis of natural
selection.
1858Cuvier publishes his extensive
studies of vertebrate fossils.
Lyell publishes
Principles of Geology.
Figure 22.2
18. Figure 22.5
Darwin in 1840,
after his return
from the
voyage
The
Galápagos
Islands
NORTH
AMERICA
ATLANTIC
OCEAN
PACIFIC
OCEAN
PACIFIC
OCEAN
Pinta
Marchena
Genovesa
Equator
Chile
Santiago
Daphne
Islands
Fernandina
Isabela Santa
Cruz
Santa
Fe San
Cristobal
Española
Kilometers
0 20 40 Florenza
Pinzón
SOUTH
AMERICA
AFRICA
EUROPE
Great
Britain
HMS Beagle in port
Equator
PACIFIC
OCEAN
Malay Archipelago
AUSTRALIA
Tasmania
New
Zealand
Brazil
Argentina
Cape Horn
AndesMtns.
Cape of
Good Hope
20. Figure 22.6
Cactus eater. The long,
sharp beak of the
cactus ground finch
(Geospiza scandens)
helps it tear and eat
cactus flowers and
pulp.
Insect eater. The green warbler finch
(Certhidea olivacea) uses its narrow,
pointed beak to grasp insects.
Seed eater. The large
ground finch (Geospiza
magnirostris) has a large
beak adapted for cracking
seeds that fall from plants
to the ground.
27. Natural Selection and Adaptation
• Evolutionary biologist Ernst Mayr has dissected
the logic of Darwin’s theory into three inferences
based on five observations
28. • Observation #1: For any species, population sizes
would increase exponentially if all individuals that
are born reproduced successfully
• Observation #2: Populations tend to be stable in
size, except for seasonal fluctuations
• Observation #3: Resources are limited
• Inference #1: Production of more individuals than
the environment can support leads to a struggle
for existence among individuals of a population,
with only a fraction of their offspring surviving
29. • Observation #4: Members of a population vary
extensively in their characteristics; no two
individuals are exactly alike
30.
31. • Observation #5: Much of this variation is heritable
• Inference #2: Survival depends in part on inherited
traits; individuals whose inherited traits give them
a high probability of surviving and reproducing are
likely to leave more offspring than other individuals
• Inference #3: This unequal ability of individuals to
survive and reproduce will lead to a gradual
change in a population, with favorable
characteristics accumulating over generations
45. LE 22-16
Percent of Amino Acids That Are
Identical to the Amino Acids in a
Human Hemoglobin Polypeptide
100%
95%
87%
69%
54%
14%
Rhesus monkey
Species
Human
Mouse
Chicken
Frog
Lamprey
49. Figure 22.19
Most mammals Cetaceans and even-toed ungulates
(a) Canis (dog) (b) Pakicetus (c) Sus (pig) (d) Odocoileus (deer)
Figure 22.19 Ankle bones: one piece of the puzzle. Comparing fossils and present- day examples of the
astragalus (a type of ankle bone) provides one line of evidence that cetaceans are closely related to even-
toed ungulates. (a) In most mammals, the astragalus is shaped like that of a dog, with a double hump on
one end (indicated by the red arrows) but not at the opposite end (blue arrow). (b) Fossils show that the
early cetacean Pakicetus had an astragalus with double humps at both ends, a unique shape that is
otherwise found only in even-toed ungulates, as shown here for (c) a pig and (d) a deer.