1. 1

2. What is evolution?
1

3. 2

4. What is natural
selection?
2

5. 100
% of green peas
80
60
40
20
50 100 150 200
Generation (t)
Genetic change within populations
3

6. 100
% of green peas
80
60
40
20
50 100 150 200
Generation (t)
Adaptation via specific phenotypes
Genetic change within populations
3

7. 100
% of green peas
80
60
40
20
50 100 150 200
Generation (t)
Adaptation via specific phenotypes
Genetic change within populations
Diversification & speciation
3

8. 100
% of green peas
80
60
40
20
50 100 150 200
Generation (t)
Adaptation via specific phenotypes
Genetic change within populations
Diversification & speciation Global biodiversity
3

9. Uniform
Formation Universal Competition Mechanism
Nested Common Mechanism nature of Natural
of new common for of
relationships descent for change physical selection
species descent resources inheritance
processes
Aristotle
Linnaeus
Buffon
E. Darwin
Lamarck
Malthus
Lyell
C. Darwin
Wallace
Mendel
Fisher
4

10. Aristotle
• Greek philosopher
• Examined natural world for evidence
of divine order
• Scala naturae (“Chain of Being”)
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5

11. Aristotle
• Greek philosopher
• Examined natural world for evidence
of divine order
• Scala naturae (“Chain of Being”)
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5

12. Carolus Linnaeus
“The father of modern taxonomy”
• Binomial system of nomenclature
• Nested system of relationships
• Recognized distinction between different
species
• Believed in balance of nature
• Eventually recognized that hybridization can form new
species
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6

13. Carolus Linnaeus
“The father of modern taxonomy”
• Binomial system of nomenclature
• Nested system of relationships
• Recognized distinction between different
species
• Believed in balance of nature
• Eventually recognized that hybridization can form new
species
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6

14. Comte de Buffon
“Dégéneration”
• Species arise via material processes
• Looked for evidence in the physical & biological world
• Believed in common descent (dégéneration)
• Change only happened within families.
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7

15. Comte de Buffon
“Dégéneration”
• Species arise via material processes
• Looked for evidence in the physical & biological world
• Believed in common descent (dégéneration)
• Change only happened within families.
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7

16. Erasmus Darwin
Charles’ Grandfather
• Believed organisms constantly adapted
to their environment
• Transformism, or transmutation
• “One living filament”
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8

17. Erasmus Darwin
Charles’ Grandfather
• Believed organisms constantly adapted
to their environment
• Transformism, or transmutation
• “One living filament”
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8

18. Thomas Malthus
Principle of overproduction
• Essay on the Principle of Population (1797)
• Geometric growth of populations inherently
leads to a struggle for existence.
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9

19. Thomas Malthus
Principle of overproduction
• Essay on the Principle of Population (1797)
• Geometric growth of populations inherently
leads to a struggle for existence.
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9

20. Thomas Malthus
Principle of overproduction
• Essay on the Principle of Population (1797)
• Geometric growth of populations inherently
leads to a struggle for existence.
http://www.pbs.org/wgbh/nova/worldbalance/numb-10.html
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9

21. Jean-Baptiste Lamarck
Inheritance of acquired characters
• French professional naturalist
• Theory of transformism
• Philosophie zoologique (1809)
• Two laws of inheritance
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10

22. Jean-Baptiste Lamarck
Inheritance of acquired characters
• French professional naturalist
• Theory of transformism
• Philosophie zoologique (1809)
• Two laws of inheritance
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10

23. Charles Lyell
Uniformitarianism
• English geologist
• Another major influence on Darwin &
Wallace
• Uniformitarianism: earth is subject to gradual,
continuous change
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11

24. Charles Lyell
Uniformitarianism
• English geologist
• Another major influence on Darwin &
Wallace
• Uniformitarianism: earth is subject to gradual,
continuous change
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11

25. Charles Darwin
The Man
• An English “gentleman of private means”
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12

26. Charles Darwin
The Voyage of the Beagle (1831–1836)
• Developed an appreciation of biogeographical patterns
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13

27. Charles Darwin
The Voyage of the Beagle (1831–1836)
• Developed an appreciation of biogeographical patterns
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13

28. Charles Darwin
Biogeography on the Beagle
• Observed similar species coexisting in
“boundary zones”
• These species must compete with each other
Rhea
(South America)
14

29. Charles Darwin
Biogeography on the Beagle
• Why do different groups of organisms live in
areas separated by barriers (like the ocean)?
Rhea Ostrich
(South America) (Africa)
15

30. Charles Darwin
Biogeography on the Beagle
• Why do different groups of organisms live in
areas separated by barriers (like the ocean)?
Galapagos Tortoises
Hood Island Tortoise Abingdon Island Tortoise
16

31. Charles Darwin
Back in Britain:
The theory of natural selection
• Darwin recognized several critical facts:
• Variability exists within species
• Variant traits may be inherited
• Many individuals must die or fail to reproduce
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17

32. Charles Darwin
Back in Britain:
The theory of natural selection
• Darwin recognized several critical facts:
• Variability exists within species
• Variant traits may be inherited
• Many individuals must die or fail to reproduce
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17

33. Charles Darwin
The origin of species
• As natural selection acts on geographically isolated
populations, they become increasingly different from
each other.
18

34. Charles Darwin
The origin of species
• As natural selection acts on geographically isolated
populations, they become increasingly different from
each other.
18

35. Alfred R. Wallace
Natural selection co-discovered
• Independently discovered natural
selection (~1858)
• “[the] self-acting process [of natural selection]
would necessarily improve the race, because in
every generation the inferior would inevitably
be killed off and the superior would remain –
that is, the fittest would survive.”
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19

36. Alfred R. Wallace
Natural selection co-discovered
• Independently discovered natural
selection (~1858)
• “[the] self-acting process [of natural selection]
would necessarily improve the race, because in
every generation the inferior would inevitably
be killed off and the superior would remain –
that is, the fittest would survive.”
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19

37. Inheritance
• The greatest weakness
of the theory of
natural selection was
lack of knowledge of
how inheritance
worked
• Blending inheritance was
assumed
20

38. Inheritance
• The greatest weakness
Grandma Grandpa
of the theory of
natural selection was
lack of knowledge of
how inheritance
worked
• Blending inheritance was
assumed
20

39. Inheritance
• The greatest weakness
Grandma Grandpa
of the theory of
natural selection was
lack of knowledge of
how inheritance
worked
• Blending inheritance was
assumed
20

40. Inheritance
• The greatest weakness
Grandma Grandpa
of the theory of
natural selection was
lack of knowledge of
how inheritance
worked
• Blending inheritance was
assumed
20

41. Inheritance
• The greatest weakness
Grandma Grandpa
of the theory of
natural selection was
lack of knowledge of
how inheritance
worked
• Blending inheritance was
assumed
20

42. Gregor Mendel
Mendelian genetics (1865)
• Mendel demonstrated
particulate inheritance
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21

43. Gregor Mendel
Mendelian genetics (1865)
• Mendel demonstrated
particulate inheritance
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21

44. Gregor Mendel
Mendelian genetics (1865)
• Mendel demonstrated Grandma Grandpa
particulate inheritance
AA aa
Aa
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21

45. Gregor Mendel
Mendelian genetics (1865)
• Mendel demonstrated Grandma Grandpa
particulate inheritance
AA aa
Aa Aa Aa
AA Aa aa
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21

46. Gregor Mendel
Mendelian genetics (1865)
• Mendel demonstrated Grandma Grandpa
particulate inheritance
AA aa
Aa Aa Aa
AA Aa aa
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21

47. R. A. Fisher
Uniting Mendelian and quantitative
genetics (1918)
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22

48. R. A. Fisher
Uniting Mendelian and quantitative
genetics (1918)
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22

49. R. A. Fisher
Uniting Mendelian and quantitative
genetics (1918)
One gene (2 alleles)
1
2
Proportion of offspring
1
4
mean - 1 mean mean +1
Phenotype (height)
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22

50. R. A. Fisher
Uniting Mendelian and quantitative
genetics (1918)
One gene (2 alleles) Ten genes (20 alleles)
1
0.175
2
0.15
Proportion of offspring
0.125
0.1
1
4
0.075
0.05
0.025
-20 20
mean - 1 mean mean +1 mean
Phenotype (height) Phenotype (height)
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22