Gen Bio II BIO102

1. Descent withDescent with
Modification:Modification:
A DarwinianA Darwinian
View of LifeView of Life
BIOLBIOL 102:102:
General Biology IIGeneral Biology II
ChapterChapter 2222
RobRob SwatskiSwatski
Associate ProfessorAssociate Professor of Biologyof Biology
HACCHACC--YorkYork

2. 2

3. 1859: Charles Darwin1859: Charles Darwin publishedpublished
TheThe OriginOrigin of Speciesof Species
3

4. Main IdeasMain Ideas
of Evolutionof Evolution
Current species
are descendants
of ancestral
species
“Descent with
modification”
Natural selection
DescendantsDescendants
AncestorAncestor
4

5. 5
Evolution accountsEvolution accounts
for the unity &for the unity &
diversity of lifediversity of life

6. TheodosiusTheodosius DobzhanskyDobzhansky
“Nothing in biology
makes sense
except in the light
of evolution.”
6

7. 7

8. 8
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 (shown in 1848)
sends Darwin his hypothesis
of natural selection.
1858Cuvier publishes his extensive
studies of vertebrate fossils.
Lyell publishes
Principles of Geology.

9. Ancient ViewsAncient Views
Aristotle
Species are fixed &
arranged on a scala
naturae
Old Testament
Species were
individually designed
by God and, therefore,
perfect
9

10. ScalaScala
NaturaeNaturae God in
Heaven
Angels
Humans
Animals
Plants
Rocks
Devil in
Hell 10

11. TaxonomyTaxonomy
Branch of biology that
classifies organisms
into taxa
1700’s: Carl Linne,
the “father of modern
taxonomy”
Viewed adaptations
as evidence that the
Creator had designed
each species for a
specific purpose 11

12. 12

13. CarlCarl LinneLinne
“You can call me
Carolus
Linnaeus”
13

14. 14

15. Species Genus Family Order Class Phylum Kingdom DomainUrsus
americanus
(American
black bear) Ursus
Ursidae
Carnivora
Mammalia
Chordata
Animalia
Eukarya
15TaxonomyTaxonomy

16. FossilsFossils
Remains or traces
of organisms from
the past
Usually found in
sedimentary rock
layers (strata)
Established the
groundwork for
Darwin’s ideas
16

17. Younger stratum
with more recent
fossils
Layers of deposited
sediment
Older stratum
with older fossils
17

18. 18

19. 19

20. 20

21. 21

22. SuedbergSuedberg Fossil PitFossil Pit
Devonian 375 MYADevonian 375 MYA22

23. 23

24. 24

25. GeologicalGeological
ViewsViews
Catastrophism Uniformitarianism
25

26. CatastrophismCatastrophism
26

27. Charles LyellCharles Lyell
Principles of GeologyPrinciples of Geology 27

28. “The
mechanisms of
“The
mechanisms of
change are
constant over
time”
UniformitarianismUniformitarianism
28

29. “The state of the natural world is the result“The state of the natural world is the result
of a long succession of events.”of a long succession of events.”
-- Charles LyellCharles Lyell
29

30. JeanJean--
BaptisteBaptiste
LamarckLamarck
Species evolve
through the use
& disuse of body
parts
Characteristics
acquired during
life are inherited
Unsupported by
evidence
30

31. Lamarck’s HypothesisLamarck’s Hypothesis
31

32. 32

33. Aren’t you gladAren’t you glad
LamarckLamarck was wrong?was wrong? 33

34. Darwin’sDarwin’s
ResearchResearch
Darwin always
had a deep
interest in science
& nature
Was a student of
medicine &
theology at
Cambridge
5-year voyage on
the Beagle after
graduation
34

35. Don’t Listen toDon’t Listen to
Your ParentsYour Parents
“You care for
nothing but
shooting, dogs, and
rat-catching. You
will be a disgrace to
yourself and your
family.”
- DR. ROBERT DARWIN35

36. Voyage ofVoyage of
thethe BeagleBeagle
Collected
specimens of South
American plants &
animals
Observed
adaptations to
many diverse
environments
Became interested
in the geographic
distribution of
species after a stop
at the Galápagos
Islands 36

37. 37
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

38. 38
The
Galápagos
Islands
PACIFIC
OCEANPinta
Marchena
Genovesa
Equator
Santiago
Daphne
Islands
Fernandina
Isabela Santa
Cruz
Santa
Fe San
Cristobal
Española
Kilometers
0 20 40 Florenza
Pinzón

39. 39

40. Darwin’sDarwin’s
Focus onFocus on
AdaptationAdaptation
Adaptation to
the environment
& speciation are
closely related
Strongly
supported by
modern biology
Galápagos
finches
40

41. CactusCactus--eatereater
41

42. InsectInsect--eatereater
42

43. SeedSeed--eatereater 43

44. Adaptive Radiation of Galápagos FinchesAdaptive Radiation of Galápagos Finches
44

45. If you had an idea thatIf you had an idea that
was going to outragewas going to outrage
society…society…
would you keepwould you keep
it to yourself?it to yourself?45

46. 46

47. 47

48. Darwin’s Two Main IdeasDarwin’s Two Main Ideas
on Evolutionon Evolution
Descent withDescent with
modificationmodification
Explains the
unity &
diversity of life
NaturalNatural
SelectionSelection
Results in
adaptive
radiation
48

49. Descent withDescent with
ModificationModification
Darwin never used the
word “evolution” in the
1st edition of Origin of
Species
“Descent with
modification”
summarized his view of
the unity of life
All organisms are related
through descent from an
ancestor that lived in the
distant past
49

50. 50

51. The “Tree ofThe “Tree of
Life”Life”
Branches
represent life’s
diversity
Darwin’s theory
meshed well with
Linnaeus’s
hierarchy
Ex: elephants
51

52. 52
Hyracoidea
(Hyraxes)
Sirenia
(Manatees
and relatives)
†Deinotherium
†Mammut
†Platybelodon
†Stegodon
†Mammuthus
Elephas maximus
(Asia)
Loxodonta africana
(Africa)
Loxodonta cyclotis
(Africa)
†Moeritherium
†Barytherium
60
Millions of years ago
34 24 5.5 2104 0
Years ago

53. 53

54. ArtificialArtificial
SelectionSelection
Darwin noted
that humans have
modified other
species
Select & breed
individuals with
desired traits
Selective
breeding =
artificial selection
54

55. 55

56. 56

57. 57
Brussels
sprouts
Kale
Selection
for leaves
Selection for
axillary (side)
buds
Selection for
apical (tip) bud
Cabbage
Broccoli
KohlrabiWild mustard
Selection
for stems
Selection
for flowers
and stems

58. FourFour
ObservationsObservations
of Natureof Nature
Made byMade by
DarwinDarwin
58

59. 1.1. Members of aMembers of a
population often varypopulation often vary
greatly in their traitsgreatly in their traits59

60. 60

61. 2.2. Traits areTraits are inheritedinherited fromfrom
parents to offspringparents to offspring61

62. 3.3. All species areAll species are
capable of producingcapable of producing
moremore offspring thanoffspring than
the environment canthe environment can
supportsupport
62

63. 4.4. Many offspring don’t surviveMany offspring don’t survive
due to lack of food or predationdue to lack of food or predation63

64. Two InferencesTwo Inferences
MadeMade by Darwinby Darwin
64

65. 1. Individuals whose
inherited traits give them
a higher probability of
surviving & reproducing
in an environment tend
to leave more offspring
than others
65

66. 2. This unequal ability of individuals
to survive & reproduce will lead to the
accumulation of favorable traits in the
population over generations66

67. ThomasThomas
MalthusMalthus
Another major
influence on Darwin
Malthus wrote about
the potential for
human population to
increase faster than
food supplies &
other resources
67

68. 68

69. Value ofValue of
BeneficialBeneficial
TraitsTraits
Traits that provide
advantages will
accumulate in the
population
This increases the
frequency of
individuals having
these adaptations
Explains the
match between
organisms & their
environment 69

70. NaturalNatural
SelectionSelection
Individuals with
certain traits
survive &
reproduce at a
higher rate than
others
This increases the
adaptation of
organisms to their
environment over
time 70

71. 71

72. 72

73. Limits ofLimits of
NaturalNatural
SelectionSelection
Can only increase or
decrease heritable
traits in a population
Individuals do not
evolve…
Populations evolve
73

74. Evolution is supported byEvolution is supported by
an overwhelming amountan overwhelming amount
of scientific evidenceof scientific evidence 74

75. Tiktaalik
the fishapod!75

76. 76

77. Direct Observations ofDirect Observations of
Evolutionary ChangeEvolutionary Change
Natural selection
in response to
introduced plant
species
The evolution of
drug-resistant
bacteria
77

78. 78
Soapberry bug with beak
inserted in balloon vine fruit
FIELD STUDYFIELD STUDY
Can a change in aCan a change in a
population’s foodpopulation’s food
source result insource result in
evolution byevolution by
natural selection?natural selection?

79. On native species,
southern Florida
Museum-specimen average
On introduced species,
central Florida
Numberofindividuals
10
8
6
4
2
0
10
8
6
4
2
0
Beak
Beak length (mm)
6 7 8 10 119
79
RESULTSRESULTS

80. 80
12,750,000
2,500,000
2,250,000
2,000,000
1,750,000
1,500,000
1,250,000
1,000,000
750,000
500,000
250,000 base pairs
Chromosome map
of S. aureus clone USA300
Key to adaptations
Methicillin resistance
Ability to colonize hosts
Increased disease severity
Increased gene exchange
(within species) and
toxin production
MRSAMRSA

81. Mosquito Resistance to DDTMosquito Resistance to DDT
81

82. Summary ofSummary of
NaturalNatural
SelectionSelection
It does not create new
traits
It edits or selects for
traits already present in
a population
The local environment
determines which traits
will be selected for or
against in a population 82

83. Fossils asFossils as
EvidenceEvidence
Species
extinction
Origin of new
taxonomic
groups
Changes within
groups over time
83

84. Bristolia insolens
10
8
0
Depth(meters)
4
Bristolia bristolensis
2
4
6
3
4
3
Latham Shale dig site,
San Bernardino County, CA84

85. Bristolia harringtoni
Bristolia mohavensis
12
14
16
18
2
Depth(meters)
1
1
2
85

86. Transitional FormsTransitional Forms
86

87. ArchaeopteryxArchaeopteryx87

88. (a)(a) PakicetusPakicetus (terrestrial)(terrestrial)
(b)(b) RhodocetusRhodocetus (mostly aquatic(mostly aquatic))
The TransitionThe Transition
to Life in the Seato Life in the Sea
88

89. DorudonDorudon (fully aquatic)(fully aquatic) 89

90. (c)(c) DorudonDorudon (fully aquatic)(fully aquatic)
(d)(d) BalaenaBalaena (recent(recent whale ancestor)whale ancestor)
Pelvis and
hind limb
Pelvis and
hind limb
90

91. HomologyHomology
Similarity resulting
from common
ancestry
Homologous
structures
Similarities that
represent variations
on a structural
theme found in a
common ancestor 91

92. Humerus
Radius
Ulna
Carpals
Metacarpals
Phalanges
HumanHuman WhaleWhaleCatCat BatBat
92

93. 93

94. 94

95. Pharyngeal
pouches
Post-anal tail
Comparative EmbryologyComparative Embryology
95

96. VestigialVestigial
StructuresStructures
Remnants of
anatomical
features
Once served
important
functions in an
organism’s
ancestors
Ex: spurs of
pythons
96

97. 97

98. MolecularMolecular
HomologiesHomologies
Genes inherited
from a common
ancestor that are
shared among
organisms
Ex: Hemoglobin
98

99. HomologiesHomologies
and “Treeand “Tree
Thinking”Thinking”
Evolutionary trees
are used to explain
homologies
Hypotheses about
relationships among
different groups
Constructed using
anatomical & DNA
sequence data
99

100. 100

101. 101
Branch point
Lungfishes
Amphibians
Mammals
Lizards
and snakes
Crocodiles
Ostriches
Hawks and
other birds
Feathers
Amnion
Digit-
bearing
limbs
Homologous
characteristic
Tetrapods
Amniotes
Birds
1
2
3
4
5
6

102. Convergent EvolutionConvergent Evolution Melbourne, AustraliaMelbourne, Australia
102

103. ConvergentConvergent
EvolutionEvolution
Similar features
(analogous traits)
can evolve in
distantly related
groups
Arise when groups
independently
adapt to similar
environments in
similar ways
Convergent
evolution does not
provide information
about ancestry
103

104. 104
Sugar
glider
Flying
squirrel
NORTH
AMERICA
AUSTRALIA

105. 105
DiacodexisDiacodexis, an early even, an early even--toed ungulatetoed ungulate

106. 106
Most mammals Cetaceans and even-toed ungulates
(a) Canis (dog) (b) Pakicetus (c) Sus (pig) (d) Odocoileus (deer)

107. 107
Other
even-toed
ungulates
Hippopotamuses
†Pakicetus
†Rodhocetus
†Dorudon
Living
cetaceans
Common
ancestor
of cetaceans
Millions of years ago
70 Key60 50 40 30 20 10 0 Pelvis Tibia
Femur Foot

108. BiogeographyBiogeography
The geographic
distribution of
species
Major influence on
Darwin’s theory
Islands have many
endemic species
closely related to
species on the
nearest island or
mainland
108

109. Mangrove island research, FL KeysMangrove island research, FL Keys
E.O. WilsonE.O. Wilson109

110. ContinentalContinental
DriftDrift
Earth’s continents
were once united in
a super-continent
called Pangaea
Have since
separated by
continental drift
Understanding
impact on species
distribution helps
predict when &
where different
groups evolved 110

111. What is a Theory?What is a Theory?What is a Theory?What is a Theory?
Broad and
general
Supported
by lots of
evidence
Generates
new
testable
hypotheses
111

112. Darwin’s TheoryDarwin’s Theory
of Evolution byof Evolution by
NaturalNatural
SelectionSelection
Integrates diverse
areas of biological
study
Ongoing research
has only advanced
& strengthened
our understanding
of evolution
Stimulates many
new research
questions 112

113. 113

114. CreditsCredits
by Rob Swatski, 2013
http://robswatskibiology.wetpaint.com
Visit my website forVisit my website for moremore Biology studyBiology study resources!resources!
http://www.flickr.com/photos/rswatski
Please send your comments and feedback to: rjswatsk@hacc.edu
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