1. Evolution and Speciation
Chapters 15 & 16
Evolution and Speciation

2. Let’s talk “evolution” first
The theory of evolution (decent with modification) by natural selection What’s is a theory?

3. Misconceptions…

7. - Acknowledgment that life on Earth has changed -
The First Hurdles
- Acknowledgment that life on Earth has changed -
Dominant religious beliefs stated that life was created at the same time as Earth. Newly discovered species were not at odds with this. The discovery of evidence of extinct species was a problem for this belief system.
There was also an issue with time. Common religious belief, taking cues from religious texts, was that the world was in the neighborhood of 4000 years old.

8. All species have always existed…
The First Hurdles…
All species have always existed…
Jean Baptist Lamarck
Use and disuse
Inheritance of acquired characters

9. All species have always existed…
The First Hurdles…
All species have always existed…
Explained changes in life without requiring species to have gone extinct

12. Jean Baptist Lamark
The mechanism for decent with modification (Evolution) is… Inheritance of Acquired Characteristics

13. Charles Darwin 1809-1882 HMS Beagle 1831
1859 – “On the Origin of Species”

17. the mechanism for decent with modification (Evolution)
Natural Selection is …
the mechanism for decent with modification (Evolution)

18. Misconceptions…
Scientist don’t debate “if” they debate “how”

19. Misconceptions…

20. Misconceptions…

24. Natural Selection can only work on traits/structures already present.
It is not perfect.

28. 4 Parts of Natural Selection
1. Overproduction 2. Genetic Variation 3. Struggle to Survive 4. Differential Reproduction

29. 1. Overproduction

31. 2. Genetic Variation

33. 3. Struggle to Survive

35. 4. Differential Reproduction

37. Populations Adapt – Individuals Can’t (They acclimatize)
Fitness = ability to make a hereditary contribution to the next generation
Populations Adapt – Individuals Can’t (They acclimatize)

38. Evidence

40. Fossils

41. Fossil Record
Strata & Superposition
Relative Age vs. Absolute Age

42. Fossil Record
Per the theory - You would expect older rock to contain mostly organisms that are less complex and less like current (living) organisms

44. Transitional Species in the Fossil Record

45. Transitional Species

46. Biogeography
The study of the location of living organisms (and fossil remains)

47. Biogeography

48. Anatomical

49. Vestigial Structures

57. Convergent Evolution

61. Analogous Structures
Similar purpose – different origin

62. Divergent Evolution
Adaptive Radiation

64. Homologous Structures

67. Adaptive Radiation

69. Coevolution

71. Molecular

72. DNA & The Genetic Code

75. Embyrological

76. Embryonic Development

79. Explaining things… (some examples of natural selection at work)

80. Artificial Selection

82. Sexual Selection

83. Relaxed Selection – Backward Evolution?

84. Altruism

85. Chapter 16 – Seeing Evolution

86. Q: How do we see evolution?
A: In populations Natural Selection acts on populations by changing the composition of the gene pool.

87. Gene Pool

89. Population Genetics
Bell Curve – Ding! You’re most likely…just average!

90. Hardy-Weinberg Equilibrium
No evolution if:
1. No net mutation occurs
2. Individuals do not leave or enter population.
3. The population is large
4. Individuals mate randomly
5. Selection does not occur

91. Non-random Mating
Sexual Selection

92. Gene Flow
Mutation
Immigration (In)
Emigration (Exit)

93. Genetic Drift – small population problems
or founder effect

94. Types of Selection

95. Directional Selection

96. Directional Selection

97. Stabilizing Selection

98. Stabilizing Selection

99. Disruptive Selection

100. Disruptive Selection

101. Types of Selection

102. What is a species?
Morphology
Biological Species Concept

105. Speciation Involves Isolation (Reproductive or Geographic)
Then adaptation

106. (Adaptation)
(Isolation)

107. Isolation

108. Reproductive Isolation
Prezygotic
Postzygotic

109. Reproductive Isolation
Prezygotic or Postzygotic?
Hybrids…
Horse = 64 Donkey = 62 Mule = 63
Liger and Tiglon

112. Reproductive Isolation

113. Reproductive Isolation

117. Allopatric Speciation
“different homelands”
Geographic Isolation

118. Sympatric Speciation
“same homeland”
Reproductive Isolation

119. Gradualism vs. Punctuated Equilibrium

120. Gradualism vs. Punctuated Equilibrium

121. Extinction

122. Phylogenetic Tree