10. 3 Schools of evolutionary thought
• Linneaus: each species was separately
created.
• Lamarck: characteristics
acquired by an
individual are passed on to offspring.
11. 3 Schools of evolutionary thought
• Linneaus: each species was separately
created.
• Lamarck: characteristics
acquired by an
individual are passed on to offspring.
• Darwin & Wallace: viewed evolution
as descent with modification.
12. Darwin’s evidence for evolution
1. The Fossil Record
2. Comparative Anatomy
3. Comparative Embryology
4. Vestigial Structures
5. Domestication (artificial selection)
13. Evolution by Natural selection
• There is inherited variation within species.
• There is competition for survival within species.
• Genetically inherited traits affect reproduction or survival. Thus
the frequencies of variants change.
15. “Neo-Darwinism”
or
“The Modern Synthesis”
The same thing... but with better
understanding of how things work.
16. “Neo-Darwinism”
or
“The Modern Synthesis”
The same thing... but with better
understanding of how things work.
• Darwin’s Theory of Evolution by Natural Selection (1859)
17. “Neo-Darwinism”
or
“The Modern Synthesis”
The same thing... but with better
understanding of how things work.
• Darwin’s Theory of Evolution by Natural Selection (1859)
• Mendel’s Laws of Heredity (1866, 1900; see SBS 008)
18. “Neo-Darwinism”
or
“The Modern Synthesis”
The same thing... but with better
understanding of how things work.
• Darwin’s Theory of Evolution by Natural Selection (1859)
• Mendel’s Laws of Heredity (1866, 1900; see SBS 008)
• Cytogenetics (1902, 1904 - )
19. “Neo-Darwinism”
or
“The Modern Synthesis”
The same thing... but with better
understanding of how things work.
• Darwin’s Theory of Evolution by Natural Selection (1859)
• Mendel’s Laws of Heredity (1866, 1900; see SBS 008)
• Cytogenetics (1902, 1904 - )
• Population Genetics (1908; see Lectures 7-12)
20. “Neo-Darwinism”
or
“The Modern Synthesis”
The same thing... but with better
understanding of how things work.
• Darwin’s Theory of Evolution by Natural Selection (1859)
• Mendel’s Laws of Heredity (1866, 1900; see SBS 008)
• Cytogenetics (1902, 1904 - )
• Population Genetics (1908; see Lectures 7-12)
• Molecular genetics (1970s- ; see SBS 633/210 and Lecture 6)
21. Today
1. Major transitions in evolution
2. Geological timescales
3. Major drivers of evolution
4. Examples of major events.
26. Major transitions: early life
• Early life:
• Replicating molecules
• Compartmentalization
• RNA world (RNA as information & enzymes)
to DNA information & protein enzymes
27. Major transitions: early life
• Early life:
• Replicating molecules
• Compartmentalization
• RNA world (RNA as information & enzymes)
to DNA information & protein enzymes
• Linkage of replicators (chromosomes)
28. Major transitions: early life
• Early life:
• Replicating molecules
• Compartmentalization
• RNA world (RNA as information & enzymes)
to DNA information & protein enzymes
• Linkage of replicators (chromosomes)
• Prokaryote to Eukaryote
37. Major transitions: eusociality
• Solitary
lifestyle --> Eusociality
1. Reproductive division of labor
2. Overlapping generations (older offspring help younger offspring)
3. Cooperative care of young
38. Major transitions: eusociality
• Solitary
lifestyle --> Eusociality
1. Reproductive division of labor
2. Overlapping generations (older offspring help younger offspring)
3. Cooperative care of young
Eg: ants, bees, wasps, termites. But also: naked mole rats, a beetle, a shrimp...
42. But “complexity of life” didn’t
increase linearly.
2. Geological time scales
43. But “complexity of life” didn’t
increase linearly.
2. Geological time scales
Defined by changes in flora and fauna (seen in fossil record).
44. But “complexity of life” didn’t
increase linearly.
2. Geological time scales
Defined by changes in flora and fauna (seen in fossil record).
Eon > Era > Period > Epoch
45. Geological timescales: Eon > Era > Period > Epoch
2 Ma:
First Hominids
230-65 Ma: 4550 Ma:
Dinosaurs
Hominids
Mammals
ca. 380 Ma: Land plants
First vertebrate land animals Animals
Multicellular life
4527 Ma:
Eukaryotes
ca. 530 Ma: Prokaryotes Formation of the Moon
Cambrian explosion 4.6 Ga
65 Ma ca. 4000 Ma: End of the
750-635 Ma: Ma Late Heavy Bombardment;
251
Two Snowball Earths first life
Cenozoic
Mes
a
M
ozoi
Ha
Pa
2
de
54
4 Ga
an
leo
Era ca. 3500 Ma:
c
zo
Era
3.8
Photosynthesis starts
Eon
ic
Era
Ga
1 Ga
Eon
n
Pro
hea
ter
Arc
oz
3 Ga
oic
Eon
2 Ga
a
2.5 G
Ma = Million years ago ca. 2300 Ma:
Atmosphere becomes oxygen-rich;
Ga = Billion years ago first Snowball Earth
46. Geological timescales: Eon > Era > Period > Epoch
2 Ma:
First Hominids
230-65 Ma: 4550 Ma:
Dinosaurs
Hominids
Mammals
ca. 380 Ma: Land plants
First vertebrate land animals Animals
Multicellular life
4527 Ma:
Eukaryotes
ca. 530 Ma: Prokaryotes Formation of the Moon
Cambrian explosion 4.6 Ga
65 Ma ca. 4000 Ma: End of the
750-635 Ma: Ma Late Heavy Bombardment;
251
Two Snowball Earths first life
Cenozoic
Mes
a
M
ozoi
Ha
Pa
2
de
54
4 Ga
an
leo
Era ca. 3500 Ma:
c
zo
Era
3.8
Photosynthesis starts
Eon
ic
Era
Ga
1 Ga
Eon
n
Pro
hea
ter
Arc
oz
3 Ga
oic
Eon
2 Ga
a
2.5 G
Ma = Million years ago ca. 2300 Ma:
Atmosphere becomes oxygen-rich;
Ga = Billion years ago first Snowball Earth
49. Geological timescales: Eon > Era > Period > Epoch
2 Ma:
First Hominids
230-65 Ma: 4550 Ma:
Dinosaurs
Hominids
Mammals
ca. 380 Ma: Land plants
First vertebrate land animals Animals
Multicellular life
4527 Ma:
Eukaryotes
ca. 530 Ma: Prokaryotes Formation of the Moon
Cambrian explosion 4.6 Ga
65 Ma ca. 4000 Ma: End of the
750-635 Ma: Ma Late Heavy Bombardment;
251
Two Snowball Earths first life
Cenozoic
Mes
a
M
ozoi
Ha
Pa
2
de
54
4 Ga
an
leo
Era ca. 3500 Ma:
c
zo
Era
3.8
Photosynthesis starts
Eon
ic
Era
Ga
1 Ga
Eon
n
Pro
hea
ter
Arc
oz
3 Ga
oic
Eon
2 Ga
a
2.5 G
Ma = Million years ago ca. 2300 Ma:
Atmosphere becomes oxygen-rich;
Ga = Billion years ago first Snowball Earth
72. 3. Major drivers of evolution
Conditions on earth change.
• Tectonic movement (of continental plates)
• Vulcanism
• Climate change
• Meteorites
73. 3. Major drivers of evolution
Meteorite impact
?
Vulcanism ? Climate change
Tectonic movement
74. 3. Major drivers of evolution
Meteorite impact
?
Vulcanism ? Climate change
Tectonic movement
Consequences:
75. 3. Major drivers of evolution
Meteorite impact
?
Vulcanism ? Climate change
Tectonic movement
Consequences: • Large scale migrations
76. 3. Major drivers of evolution
Meteorite impact
?
Vulcanism ? Climate change
Tectonic movement
Consequences: • Large scale migrations
• Speciation
77. 3. Major drivers of evolution
Meteorite impact
?
Vulcanism ? Climate change
Tectonic movement
Consequences: • Large scale migrations
• Speciation
• Mass extinctions
78. 3. Major drivers of evolution
Meteorite impact
?
Vulcanism ? Climate change
Tectonic movement
Consequences: • Large scale migrations
• Speciation
• Mass extinctions
• Adaptive radiations
79. 3. Major drivers of evolution
Meteorite impact
?
Vulcanism ? Climate change
Tectonic movement
Consequences: • Large scale migrations
• Speciation
• Mass extinctions
• Adaptive radiations
80. 3. Major drivers of evolution
Meteorite impact
?
Vulcanism ? Climate change
Tectonic movement
Consequences: • Large scale migrations
• Speciation
• Mass extinctions
• Adaptive radiations
82. Today
1. Major transitions in evolution
2. Geological timescales
3. Major drivers of evolution
4. Examples of major events: two recent extinctions
83. 4. Recent major exinction
fraction of genera
present in each time
interval but extinct in
the following interval
Pg
r
T
P-
T)
(K
g
-P
J
-S
r-
D
K
O
T
te
La
ay
o d
T
84. 4. Recent major exinction
fraction of genera
present in each time
interval but extinct in
the following interval
Pg
r
T
P-
T)
(K
g
-P
J
-S
r-
D
K
O
T
te
La
ay
o d
T
85. 4. Recent major exinction
fraction of genera
present in each time
interval but extinct in
the following interval
Pg
r
T
P-
T)
(K
g
-P
J
-S
r-
D
K
O
T
te
La
ay
o d
T
86. 4. Recent major exinction
fraction of genera
present in each time
interval but extinct in
the following interval
Pg
r
T
P-
T)
(K
g
-P
J
-S
r-
D
K
O
T
te
La
ay
o d
T
89. Late Carboniferous 306 Mya
• Tetrapods and early amniotes.
• Tropical conditions around equatorial landmasses.
90. Late Carboniferous 306 Mya
• Tetrapods and early amniotes.
• Tropical conditions around equatorial landmasses.
• Damp forests: tall trees & lush undergrowth: giant club mosses,
lycopods, ferns & seed ferns.
91. Late Carboniferous 306 Mya
• Tetrapods and early amniotes.
• Tropical conditions around equatorial landmasses.
• Damp forests: tall trees & lush undergrowth: giant club mosses,
lycopods, ferns & seed ferns.
• Decaying undergrowth forms coal.
92. Late Carboniferous 306 Mya
• Tetrapods and early amniotes.
• Tropical conditions around equatorial landmasses.
• Damp forests: tall trees & lush undergrowth: giant club mosses,
lycopods, ferns & seed ferns.
• Decaying undergrowth forms coal.
• Good habitats for terrestrial invertebrates including spiders,
millipedes and insects (e.g. giant dragonflies).
95. Permian-Triassic Extinction
Went extinct:
•Up to 96% of marine species & 70% of terrestrial vertebrates
•21 terrestrial tetrapod families (63%)
• 7 orders of insects
Sun et al Science 2012
96. Permian-Triassic Extinction
Went extinct:
•Up to 96% of marine species & 70% of terrestrial vertebrates
•21 terrestrial tetrapod families (63%)
• 7 orders of insects
Sun et al Science 2012
97. Jurassic/Cretaceous
•Mammal-like reptiles were replaced
as dominant land vertebrates by
reptiles (dinosaurs).
• Lizards, modern amphibians and
early birds appear.
• The conifer- and fern-dominated
vegetation of the Late Triassic
continued into the Jurassic.
100. Cretaceous–Paleogene (KT) extinction
66 million years ago
75% of all species became extinct (50% of genera).
Including:
Mosasaur
Ammonite (marine reptile)
101. Cretaceous–Paleogene (KT) extinction
66 million years ago
75% of all species became extinct (50% of genera).
Including:
Mosasaur
Ammonite (marine reptile) Non-bird
dinosaurs
102. Cretaceous–Paleogene (KT) extinction
66 million years ago
75% of all species became extinct (50% of genera).
Including:
Mosasaur
Ammonite (marine reptile) Non-bird
dinosaurs
Most Plant-eating insects
103. Cretaceous–Paleogene (KT) extinction
66 million years ago
75% of all species became extinct (50% of genera).
Including:
Mosasaur
Ammonite (marine reptile) Non-bird
dinosaurs
Most Plant-eating insects
Subsequently, many adaptive radiations to fill newly vacant niches.
eg. mammals, fish, many insects
111. Cretaceous–Paleogene (KT) extinction
66 million years ago
• Bolide impact at Chixulub.
• huge tsunamis
• cloud of dust and water vapour, blocking sun.
112. Cretaceous–Paleogene (KT) extinction
66 million years ago
• Bolide impact at Chixulub.
• huge tsunamis
• cloud of dust and water vapour, blocking sun.
• plants & phytoplankton die (bottom of food chain)
--> animals starve
113. Cretaceous–Paleogene (KT) extinction
66 million years ago
• Bolide impact at Chixulub.
• huge tsunamis
• cloud of dust and water vapour, blocking sun.
• plants & phytoplankton die (bottom of food chain)
--> animals starve
• dramatic climate & temperature changes are
difficult (easier for warm-blooded?)
114. Cretaceous–Paleogene (KT) extinction
66 million years ago
• Bolide impact at Chixulub.
• huge tsunamis
• cloud of dust and water vapour, blocking sun.
• plants & phytoplankton die (bottom of food chain)
--> animals starve
• dramatic climate & temperature changes are
difficult (easier for warm-blooded?)
• Additional causes?
115. Cretaceous–Paleogene (KT) extinction
66 million years ago
• Bolide impact at Chixulub.
• huge tsunamis
• cloud of dust and water vapour, blocking sun.
• plants & phytoplankton die (bottom of food chain)
--> animals starve
• dramatic climate & temperature changes are
difficult (easier for warm-blooded?)
• Additional causes?
• Some groups were ALREADY in decline
116. Cretaceous–Paleogene (KT) extinction
66 million years ago
• Bolide impact at Chixulub.
• huge tsunamis
• cloud of dust and water vapour, blocking sun.
• plants & phytoplankton die (bottom of food chain)
--> animals starve
• dramatic climate & temperature changes are
difficult (easier for warm-blooded?)
• Additional causes?
• Some groups were ALREADY in decline
• Additional impacts?
117. Cretaceous–Paleogene (KT) extinction
66 million years ago
• Bolide impact at Chixulub.
• huge tsunamis
• cloud of dust and water vapour, blocking sun.
• plants & phytoplankton die (bottom of food chain)
--> animals starve
• dramatic climate & temperature changes are
difficult (easier for warm-blooded?)
• Additional causes?
• Some groups were ALREADY in decline
• Additional impacts?
• Deccan traps (India) - 30,000 years
of volcanic activity (lava/gas release)
119. Summary.
• The history of the earth is divided into geological time periods
• These are defined by characteristic flora and fauna
• Large-scalechanges in biodiversity were triggered by continental
movement and catastrophic events (mass extinctions)