1. Argentina
Australia
C. Observations
4. Biogeography
- Community Convergence
In similar environments, there are organisms that fill similar ecological roles – and they are morphologically similar.
Correlated patterns…

2. C. Observations
4. Biogeography – Island Faunas

3. C. Observations
4. Biogeography – Island Fauna
- Fauklands – species same as mainland
- Galapagos – species different from mainland
a. degree of isolation correlated with uniqueness of inhabitants…..

4. Voyage of the Beagle – Darwin (1845) "The natural history of these islands is eminently curious, and well deserves attention. Most of the organic productions are aboriginal creations, found nowhere else;
Flightless Cormorant

5. “…there is even a difference between the inhabitants of the different islands; yet all show a marked relationship with those of America, though separated from that continent by an open space of ocean, between 500 and 600 miles in width.”
Green Iguana – Central and South America

6. “…The archipelago is a little world within itself, or rather a satellite attached to America, whence it has derived a few stray colonists, and has received the general character of its indigenous productions. Considering the small size of the islands, we feel the more astonished at the number of their aboriginal beings, and at their confined range.”
Galapagos Land Iguana, pallid species, only on Santa Fe island.

7. “… Seeing every height crowned with its crater, and the boundaries of most of the lava streams still distinct, we are led to believe that within a period geologically recent the unbroken ocean was here spread out.”

8. “…Hence, both in space and time, we seem to be brought somewhat near to that great fact -- that mystery of mysteries -- the first appearance of new beings on this earth.”
The Voyage of the Beagle – Charles Darwin

20. C. Observations
4. Biogeography – Island Faunas
a. Isolation correlates with uniqueness

21. C. Observations
4. Biogeography – Island Faunas
a. Isolation correlates with uniqueness
b. islands are dominated by dispersive forms

22. C. Observations
4. Biogeography – Island Faunas
a. Isolation correlates with uniqueness
b. islands are dominated by dispersive forms
c. there is even variation among islands

23. - Finches

24. "Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends."

25. - Mockingbirds

26. - Mockingbirds
Darwin classified four varieties of one species:
One species

27. - Mockingbirds
John Gould, the premiere ornithologist of the day, classified these as four species:

28. - Mockingbirds
Darwin began to think… could the variation WITHIN species eventually lead to variation BETWEEN species?
Could organisms in a species become so different that they become different species?

29. C. Observations
4. Biogeography – Island Faunas
- How did these animals get here?
Everything points to migration from Americas

30. C. Observations
4. Biogeography – Island Faunas
- How did these animals get here?
Everything points to migration
- But if ancestors migrated from Americas,

31. C. Observations
4. Biogeography – Island Faunas
- How did these animals get here?
Everything points to migration
- But if ancestors migrated from Americas,
then the species must have changed over time
into the species we observe there today….
Because they are not the same.

32. C. Observations
5. Argument for Evolution as Historical Fact:
P1: Species that are alive today are different from those that have lived previously.
P2: Spontaneous Generation is refuted, so organisms only come from other organisms.
C1: Thus, the organisms alive today must have come from those pre-existing, yet different, species.
C2: There must have been change through time (evolution).
Corollary: The fossil record, vestigial organs, and homologies are all explicable and logical in this context, and inexplicable (even heritical) in some theological contexts (imperfection).

33. I. Darwin’s Contributions
A. His Life
B. Origin of Species
C. Observations
D. Hypothesis – How Change Occurs

34. D. Hypothesis – How Change Occurs
1. Transitional Observations
a. Domesticated Animals

35. D. Hypothesis – How Change Occurs
1. Transitional Observations
a. Domesticated Animals

36. D. Hypothesis – How Change Occurs
1. Transitional Observations
a. Domesticated Animals
Humans can change the characteristics of a species by ‘selecting’ for particular traits. This can lead to the expression of extreme variation, well beyond the original range of variation in the initial group.
Selection can create…. There are no wolves that are as small as Chihuahuas…

37. D. Hypothesis – How Change Occurs
1. Transitional Observations
b. 1844: Darwin Reads Malthus - Essay On the Principle of Population (1798)
Thomas Malthus ( )

38. D. Hypothesis – How Change Occurs
1. Transitional Observations
b. 1844: Darwin Reads Malthus - Essay On Population
P1: All populations have the capacity to ‘over-reproduce’
P2: Resources are finite
C: There will be a “struggle for existence”… most
offspring born will die before reaching reproductive age.

39. D. Hypothesis – How Change Occurs
2. Natural Selection
P1: All populations have the capacity to ‘over-reproduce’
P2: Resources are finite
C: There will be a “struggle for existence”
P3: Organisms in a population vary, and some of this variation is heritable

40. D. Hypothesis – How Change Occurs
2. Natural Selection
P1: All populations have the capacity to ‘over-reproduce’
P2: Resources are finite
C: There will be a “struggle for existence”
P3: Organisms in a population vary, and some of this variation is heritable
C2: Some organisms, as a consequence of their inherited traits, will be more likely to survive and reproduce than others. There will be “differential reproductive success.”

41. D. Hypothesis – How Change Occurs
2. Natural Selection
C2: Some organisms, as a consequence of their inherited traits, will be more likely to survive and reproduce than others. There will be “differential reproductive success.”
C3: So, adaptive traits will be passed on in a population at higher frequency than less adaptive traits. These adaptive traits will accumulate in a population. The population will change over time. LINEAGE EVOLUTION.

42. D. Hypothesis – How Change Occurs
2. Natural Selection
C2: Some organisms, as a consequence of their inherited traits, will be more likely to survive and reproduce than others. There will be “differential reproductive success.”
C3: Over time, adaptive traits will be passed on in a population at higher frequency than less adaptive traits. These adaptive traits will accumulate in a population. The population will change over time. LINEAGE EVOLUTION.
Corollary: Two populations, adapting to different environments, will become different from one another; perhaps so different that they are unable to mate, and are different species RADIATIONAL EVOLUTION.

43. E. Dilemmas
1. Evolution of complex traits

44. E. Dilemmas
1. Evolution of complex traits

45. E. Dilemmas
1. Evolution of complex traits
- "we should be extremely cautious in concluding that an organ could not have been formed by transitional gradations of some kind. Numerous cases could be given in the lower animals of organs performing at the same time wholly distinct functions"

46. ? E. Dilemmas 1. Evolution of complex traits
2. Where are the continuous sequences of transitional forms, both through time and at present (connecting existing species?) X X X X ? X X X X X

47. E. Dilemmas
1. Evolution of complex traits
2. Where are the continuous sequences of transitional forms?
the fossil record is incomplete – not all species leave a fossil
Keep looking…

48. E. Dilemmas
1. Evolution of complex traits
2. Where are the continuous sequences of transitional forms?
1861:
Archeopteryx Lithographica

49. E. Dilemmas
1. Evolution of complex traits
2. Where are the continuous sequences of transitional forms?
- Connecting species:
Adapted forms swamp intermediates, which are typically rare and are not as 'perfected' as adapted forms...

50. E. Dilemmas
1. Evolution of complex traits
2. Where are the continuous sequences of transitional forms?
3. How are instincts evolved?

51. E. Dilemmas
1. Evolution of complex traits
2. Where are the continuous sequences of transitional forms?
3. How are instincts evolved?
close study demonstrates that instincts also vary; so selection can act on them if they are heritable like a morphological trait.

52. E. Dilemmas
1. Evolution of complex traits
2. Where are the continuous sequences of transitional forms?
3. How are instincts evolved?
4. How do sterility barriers evolve? And how are sterile castes selected for???

53. E. Dilemmas
1. Evolution of complex traits
2. Where are the continuous sequences of transitional forms?
3. How are instincts evolved?
4. How do sterility barriers evolve? And how are sterile castes selected for???
5. Source of heritable variation?

54. E. Dilemmas
1. Evolution of complex traits
2. Where are the continuous sequences of transitional forms?
3. How are instincts evolved?
4. How do sterility barriers evolve? And how are sterile castes selected for???
5. Source of heritable variation?
- Natural selection should “weed out” poorly adapted forms over time, making the organisms in the population more similar (less variation).
Why is there still so much variation in natural populations?

55. E. Dilemmas
1. Evolution of complex traits
2. Where are the continuous sequences of transitional forms?
3. How are instincts evolved?
4. How do sterility barriers evolve? And how are sterile castes selected for???
5. Source of heritable variation?
- and if heredity is governed by blending traits, then how is variation produced generation after generation?

56. E. Dilemmas
1. Evolution of complex traits
2. Where are the continuous sequences of transitional forms?
3. How are instincts evolved?
4. How do sterility barriers evolve? And how are sterile castes selected for???
5. Source of heritable variation?
- Darwin’s explanations:
- Lamarckian “use and disuse”
- and ‘gemmules’…

57. F. Darwinian Evolution
1. Darwin’s Model
Sources of Variation Causes of Change
????????????????  VARIATION  NATURAL SELECTION
(use and disuse??)

58. F. Darwinian Evolution
2. A Summary of Darwin's Theories (from Mayr)
- Evolution as such - change over time
- Common Descent - not Lamarckian transformationalism
- Gradualism - incremental, uniformitarian change
- Populational Change in Frequencies of Traits
not changes in individuals becoming perfect
- Natural Selection - changes due to differential
reproductive success

59. Post Darwinian Developments
I. Physics
A. The Age of the Earth
William Thompson - "Lord Kelvin"
Henri Becquerel
- discovers emission of Uranium
Pierre and Marie Curie
- discover emission from new element - Radium
Ernst Rutherford
- "The discovery of the radio-active elements, which in their disintegration liberate enormous amounts of energy, thus increases the possible limit of the duration of life on this planet, and allows the time claimed by the geologist and biologist for the process of evolution."

60. Post Darwinian Developments
II. Geology
A. The Dynamic Earth

61. Post Darwinian Developments
II. Geology
A. The Dynamic Earth
Continental Drift
Alfred Wegener

62. - Not accepted until the 1960’s and 1970’s, when sea floor spreading was observed, sonar was used to map the ocean, and paleomagnetism demonstrated where continents had been in the past relative to magnetic north.

63. - North and South Atlantic and Indian Ocean Basins.

64. Post Darwinian Developments
III. Paleontology
A. Intermediate Fossils

65. FISH AMPHIBIANS
Ichthyostega
- Fins and gill covers (FISH)
- Feet (AMPHIBIANS)
- After fish, before amphibians (just where evolution predicts it should be)
XXX

66. D. Devonian ( mya)
- Placoderms
- Sharks
- Lobe-finned Fishes
365 mya
385 mya

67. Archeopteryx
- Fingers, teeth, tail (Reptiles)
Feathers (birds)
- After reptiles, before birds (just where evolution predicts it should be)
REPTILES BIRDS
XXX

68. Therapsids
REPTILES MAMMALS
- Mammalian skeleton
Intermediate ear
- scales
- After reptiles, before mammals (just where evolution predicts it should be)
XXX

69. Mammals from the Jurassic (185 mya)
Therapsids from the Permian (280 mya) to the Triassic (200mya)
Pelycosaur Reptiles of the Carboniferous (300 mya)

70. Australopithecines
Australopithecus afarensis

71. Legs

72. Australopithecines
bipedal (human trait)
chimp-sized cranial volume
APES HUMANS
- After apes, before humans (just where evolution predicts it should be)
XXX

73. Post-Darwinian Facts
I. Physics
II. Geology/Paleontology
III. Genetics

74. Post-Darwinian Facts
I. Physics
II. Geology/Paleontology
III. Genetics
- Genetic info is particulate (no blending)
- Variation produced by new combinations of particles (crossing over and ind. assort.)

75. Post-Darwinian Facts
I. Physics
II. Geology/Paleontology
III. Genetics
IV. The Modern Synthesis – 1940’s

76. Sources of Variation Agents of Change Mutation N.S.
The Modern Synthetic Theory of Evolution
Sources of Variation Agents of Change
Mutation N.S.
Recombination Drift
- crossing over Migration
- independent assortment Mutation
Non-random Mating
VARIATION
So, if NO AGENTS are acting on a population, then it will be in equilibrium and WON'T change.

77. Beyond the Synthesis
1. Peripatric Speciation (Mayr)

78. Beyond the Synthesis
1. Peripatric Speciation (Mayr)
2. Punctuated Equilibrium (Eldridge and Gould – 1972)

79. - 1972 - Eldridge and Gould - Punctuated Equilibrium
1. Consider a large, well-adapted population
VARIATION
TIME

80. - 1972 - Eldridge and Gould - Punctuated Equilibrium
1. Consider a large, well-adapted population
Effects of Selection and Drift are small - little change over time
VARIATION
TIME

81. - 1972 - Eldridge and Gould - Punctuated Equilibrium
2. There are always small sub-populations "budding off" along the periphery of a species range...
VARIATION
TIME

82. X X X - 1972 - Eldridge and Gould - Punctuated Equilibrium
2. Most will go extinct, but some may survive...
VARIATION X X X
TIME

83. X X X - 1972 - Eldridge and Gould - Punctuated Equilibrium
2. These surviving populations will initially be small, and in a new environment...so the effects of Selection and Drift should be strong...
VARIATION X X X
TIME

84. X X X - 1972 - Eldridge and Gould - Punctuated Equilibrium
3. These populations will change rapidly in response...
VARIATION X X X
TIME

85. X X X - 1972 - Eldridge and Gould - Punctuated Equilibrium
3. These populations will change rapidly in response... and as they adapt (in response to selection), their populations should increase in size (because of increasing reproductive success, by definition).
VARIATION X X X
TIME

86. X X X - 1972 - Eldridge and Gould - Punctuated Equilibrium
3. As population increases in size, effects of drift decline... and as a population becomes better adapted, the effects of selection decline... so the rate of evolutionary change declines...
VARIATION X X X
TIME

87. X X X - 1972 - Eldridge and Gould - Punctuated Equilibrium
4. And we have large, well-adapted populations that will remain static as long as the environment is stable...
VARIATION X X X
TIME

88. X X X - 1972 - Eldridge and Gould - Punctuated Equilibrium
5. Since small, short-lived populations are less likely to leave a fossil, the fossil record can appear 'discontinuous' or 'imperfect'
VARIATION X X X
TIME

89. X X X - 1972 - Eldridge and Gould - Punctuated Equilibrium
5. Large pop's may leave a fossil....
VARIATION X X X
TIME

90. X X X - 1972 - Eldridge and Gould - Punctuated Equilibrium
5. Small, short-lived populations probably won't...
VARIATION X X X
TIME

91. X X X - 1972 - Eldridge and Gould - Punctuated Equilibrium
6. So, the discontinuity in the fossil record is an expected result of our modern understanding of how evolution and speciation occur...
VARIATION X X X
TIME

92. X X X - 1972 - Eldridge and Gould - Punctuated Equilibrium
6. both in time (as we see), and in SPACE (as changing populations are probably NOT in same place as ancestral species).
VARIATION X X X
TIME

93. Beyond the Synthesis
1. Peripatric Speciation (Mayr)
2. Punctuated Equilibrium (Eldridge and Gould – 1972)
3. Evo-devo: the importance of developmental programs

94. Evo-Devo – the influence of developmental programs
1. Core Processes
- Basic biological processes are CONSERVED, and the enzymes that perform them are CONSERVED:
- Many enzymes are more than 50% similar in AA sequence in E. coli and H. sapiens, though separated by 2 billion years of divergence.
- Of 548 metabolic enzymes in E. coli, 50% are present in ALL LIFE, and only 13% are unique to bacteria.

95. Evo-Devo – the influence of developmental programs
1. Core Processes
- Basic biological processes are CONSERVED, and the enzymes that perform them are CONSERVED:
- Many enzymes are more than 50% similar in AA sequence in E. coli and H. sapiens, though separated by 2 billion years of divergence.
- Of 548 metabolic enzymes in E. coli, 50% are present in ALL LIFE, and only 13% are unique to bacteria.
- So the variation and diversity of life is NOT due to changes in metabolic or structural genes... we are all built out of the same stuff, that works the same way at a cellular level.

96. Evo-Devo – the influence of developmental programs
- Variation is largely due to HOW these processes are REGULATED cell types in humans, all descended from the zygote; all genetically the same.
- Best (and most fundamental) examples are HOX genes. These are 'homeotic genes' that produce a variety of transcription factors. The production and localization of these transcription factors are CRITICAL in determining the ‘developmental compartments' of bilaterally symmetrical animals.

97. Evo-Devo – the influence of developmental programs
- Effects can be profound
- 'Master Switches' that initiate downstream cascades that can be very different... like compound or vertebrate eyes.

98. VARIATION Beyond the Synthesis Sources of Variation Agents of Change
Selection
Drift
Mutation
Migration
Non-Random Mating
Mutation
Recombination
PHYSIOLOGY
DEVELOPMENT
VARIATION