BIOL 102 Chp 22 Descent with Modification: A Darwinian View of Life

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BIOL 102 Chp 22 Descent with Modification: A Darwinian View of Life

  1. 1. Chapter 22Descent withModification: A Darwinian View of Life BIOL 102:General Biology II Rob SwatskiAssociate Professor of Biology HACC- HACC-York
  2. 2. 2
  3. 3. 1859: Charles Darwin publishedThe Origin of Species 3
  4. 4. Main Ideasof Evolution Descendants Current species are descendants of ancestral species “Descent with modification” Natural selection Ancestor 4
  5. 5. Evolution accountsfor the unity &diversity of life 5
  6. 6. Theodosius Dobzhansky “Nothing in biology makes sense except in the light of evolution.” 6
  7. 7. 7
  8. 8. 1809 Lamarck publishes his hypothesis of evolution. 1798 Malthus publishes“Essay on the Principle of Population.” 1812 Cuvier publishes his extensive 1858 1795 studies of vertebrate fossils. While studying species inHutton proposes the Malay Archipelago, his principle of 1830 Wallace (shown in 1848) gradualism. Lyell publishes sends Darwin his hypothesis Principles of Geology. of natural selection. 1790 1870 1809 183136 1859 Charles Darwin Darwin travels around On the Origin of is born. the world on HMS Species is published. Beagle. 1844 Darwin writes his essay on descent with modification. The Galápagos Islands 8
  9. 9. Ancient ViewsAristotle Old Testament Species were Species are fixed & individually designed arranged on a scala by God and, therefore, naturae perfect 9
  10. 10. Scala God inNaturae Heaven Angels Humans Animals Plants Rocks Devil in Hell 10
  11. 11. Taxonomy 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. 12
  13. 13. Carl Linne“You can call me Carolus Linnaeus” 13
  14. 14. 14
  15. 15. Ursus Species Genus Family Order Class Phylum Kingdom Domainamericanus(American Ursusblack bear) Ursidae Carnivora Mammalia Chordata Animalia EukaryaTaxonomy 15
  16. 16. FossilsRemains or tracesof organisms from the past Usually found insedimentary rock layers (strata) Established the groundwork for Darwin’s ideas 16
  17. 17. Layers of deposited sedimentYounger stratumwith more recentfossilsOlder stratumwith older fossils 17
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  19. 19. 19
  20. 20. 20
  21. 21. 21
  22. 22. Suedberg Fossil Pit22 Devonian 375 MYA
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  24. 24. 24
  25. 25. Geological ViewsCatastrophism Uniformitarianism 25
  26. 26. Catastrophism 26
  27. 27. Charles LyellPrinciples of Geology 27
  28. 28. Uniformitarianism “The mechanisms of change are constant over time” 28
  29. 29. “The state of the natural world is the resultof a long succession of events.”- Charles Lyell 29
  30. 30. Jean- Jean-BaptisteLamarck Species evolvethrough the use& disuse of body parts Characteristics acquired duringlife are inheritedUnsupported by evidence 30
  31. 31. Lamarck’s Hypothesis 31
  32. 32. 32
  33. 33. Aren’t you gladLamarck was wrong? 33
  34. 34. Darwin’sResearch Darwin always had a deepinterest in science & natureWas a student of medicine & theology at Cambridge5-year voyage onthe Beagle after graduation 34
  35. 35. Don’t Listen to Your Parents “You care for nothing but shooting, dogs, and rat-catching. You will be a disgrace to yourself and your family.”35 - DR. ROBERT DARWIN
  36. 36. Voyage ofthe Beagle 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, HMS Beagle in portafter his returnfrom thevoyage Great Britain EUROPE NORTH AMERICA ATLANTIC OCEANThe AFRICAGalápagos PACIFIC Pinta OCEANIslands Genovesa Equator Marchena SOUTH Malay Archipelago Equator AMERICA PACIFIC Santiago Daphne OCEAN Brazil Andes Mtns. Islands Chile Pinzón AUSTRALIAFernandina PACIFIC Isabela Santa Santa OCEAN Cape of Cruz Fe San Argentina Good Hope Cristobal0 20 40 Tasmania Florenza Española Kilometers Cape Horn New Zealand 37
  38. 38. TheGalápagos PACIFICIslands Pinta OCEAN Genovesa Marchena Equator Santiago Daphne IslandsFernandina Pinzón Isabela Santa Santa Cruz Fe San Cristobal0 20 40 Florenza EspañolaKilometers 38
  39. 39. 39
  40. 40. Darwin’s Focus onAdaptation Adaptation to the environment & speciation are closely related Strongly supported by modern biology Galápagos finches 40
  41. 41. Cactus-Cactus-eater 41
  42. 42. Insect- Insect-eater42
  43. 43. Seed-Seed-eater 43
  44. 44. Adaptive Radiation of Galápagos Finches 44
  45. 45. If you had an idea that was going to outrage society… would you keep45 it to yourself?
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  47. 47. 47
  48. 48. Darwin’s Two Main Ideas on Evolution Descent with Natural modification Selection Explains the Results in unity & adaptive diversity of life radiation 48
  49. 49. Descent withModification 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. 50
  51. 51. The “Tree of 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) †Moeritherium †Barytherium †Deinotherium †Mammut †Platybelodon †Stegodon †Mammuthus Elephas maximus (Asia) Loxodonta africana (Africa) Loxodonta cyclotis (Africa)60 34 24 5.5 2 104 0 Millions of years ago Years ago 52
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  54. 54. ArtificialSelection Darwin notedthat humans have modified other species Select & breed individuals with desired traits Selective breeding =artificial selection 54
  55. 55. 55
  56. 56. 56
  57. 57. Cabbage Selection for apical (tip) bud Brussels sprouts Selection for Selection Broccoli axillary (side) for flowers buds and stems Selection for stems Selection for leavesKale Wild mustard Kohlrabi 57
  58. 58. FourObservations of Nature Made by Darwin 58
  59. 59. 1. Members of a population often vary59 greatly in their traits
  60. 60. 60
  61. 61. 2. Traits are inherited from61 parents to offspring
  62. 62. 3. All species arecapable of producingmore offspring thanthe environment cansupport 62
  63. 63. 4. Many offspring don’t survive63 due to lack of food or predation
  64. 64. Two InferencesMade by Darwin 64
  65. 65. 1. Individuals whoseinherited traits give them a higher probability of surviving & reproducing in an environment tend to leave more offspring than others 65
  66. 66. 2. This unequal ability of individuals to survive & reproduce will lead to the accumulation of favorable traits in the66 population over generations
  67. 67. ThomasMalthus Another major influence on DarwinMalthus wrote about the potential forhuman population to increase faster than food supplies & other resources 67
  68. 68. 68
  69. 69. Value ofBeneficial Traits 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. 70. NaturalSelection Individuals with certain traits survive & reproduce at a higher rate than others This increases the adaptation of organisms to their environment over time 70
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  73. 73. Limits of NaturalSelection Can only increase or decrease heritable traits in a population Individuals do not evolve… Populations evolve 73
  74. 74. Evolution is supported byan overwhelming amountof scientific evidence 74
  75. 75. Tiktaalik75 the fishapod!
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  77. 77. Direct Observations of Evolutionary ChangeNatural selection The evolution of in response to drug-resistantintroduced plant bacteria species 77
  78. 78. Can a change in apopulation’s food FIELD STUDYsource result inevolution bynatural selection? Soapberry bug with beak inserted in balloon vine fruit 78
  79. 79. RESULTS Beak 10 On native species, 8 southern Florida 6 4 Number of individuals 2 0 Museum-specimen average 10 8 On introduced species, central Florida 6 4 2 0 6 7 8 9 10 11 Beak length (mm) 79
  80. 80. MRSA 2,750,000 1 250,000 base pairs 2,500,000 Chromosome map of S. aureus clone USA300 500,000 2,250,000 Key to adaptations Methicillin resistance Ability to colonize hosts 750,000 Increased disease severity 2,000,000 Increased gene exchange (within species) and toxin production 1,000,000 1,750,000 1,250,000 1,500,000 80
  81. 81. Mosquito Resistance to DDT 81
  82. 82. Summary of Natural Selection 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. 83. Fossils asEvidence Species extinction Origin of new taxonomic groups Changes within groups over time 83
  84. 84. 0 2 4 Depth (meters) 4 6 4 Bristolia insolens 8 3 Bristolia bristolensis 10 3 Latham Shale dig site,84 San Bernardino County, CA
  85. 85. Depth (meters) 12 2 Bristolia harringtoni 14 16 18 1 Bristolia mohavensis 21 85
  86. 86. Transitional Forms 86
  87. 87. 87 Archaeopteryx
  88. 88. The Transitionto Life in the Sea (a) Pakicetus (terrestrial) (b) Rhodocetus (mostly aquatic) aquatic) 88
  89. 89. Dorudon (fully aquatic) 89
  90. 90. (c) Dorudon (fully aquatic) Pelvis and hind limb Pelvis and hind limb(d) Balaena (recent whale ancestor) 90
  91. 91. Homology Similarity resulting from common ancestry Homologous structures Similarities that represent variations on a structural theme found in a common ancestor 91
  92. 92. HumerusRadiusUlnaCarpalsMetacarpalsPhalanges Human Cat Whale Bat 92
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  95. 95. Comparative Embryology Pharyngeal pouches Post-anal tail 95
  96. 96. VestigialStructures Remnants of anatomical features Once served important functions in an organism’s ancestors Ex: spurs of pythons 96
  97. 97. 97
  98. 98. MolecularHomologies Genes inherited from a common ancestor that are shared among organisms Ex: Hemoglobin 98
  99. 99. Homologies and “Tree Thinking” Evolutionary trees are used to explain homologies Hypotheses about relationships among different groups Constructed using anatomical & DNA sequence data 99
  100. 100. 100
  101. 101. Branch point Lungfishes 1 Amphibians Tetrapods Mammals AmniotesDigit- 2bearinglimbs Lizards 3 Amnion and snakes 4 Crocodiles Homologous characteristic 5 Ostriches Birds 6 Feathers Hawks and other birds 101
  102. 102. Melbourne, AustraliaConvergent Evolution 102
  103. 103. Convergent Evolution 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. NORTHSugar AMERICAglider AUSTRALIA Flying squirrel 104
  105. 105. Diacodexis,Diacodexis, an early even-toed ungulate even- 105
  106. 106. Most mammals Cetaceans and even-toed ungulates(a) Canis (dog) (b) Pakicetus (c) Sus (pig) (d) Odocoileus (deer) 106
  107. 107. Other even-toed ungulates Hippopotamuses †Pakicetus †RodhocetusCommonancestor †Dorudonof cetaceans Living cetaceans70 60 50 40 30 20 10 0 Key Pelvis Tibia Millions of years ago Femur Foot 107
  108. 108. Biogeography 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. 109. Mangrove island research, FL Keys109 E.O. Wilson
  110. 110. Continental Drift 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. 111. What is a Theory? Generates SupportedBroad and new by lots of general testable evidence hypotheses 111
  112. 112. Darwin’s Theoryof Evolution by Natural Selection Integrates diverse areas of biological study Ongoing research has only advanced & strengthened our understanding of evolution Stimulates many new research questions 112
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  114. 114. Credits by Rob Swatski, 2013 Visit my website for more Biology study resources! http://robswatskibiology.wetpaint.com http://www.flickr.com/photos/rswatskiPlease send your comments and feedback to: rjswatsk@hacc.eduImages used in this work bear a This work bears an Creative Commons license and Attribution-Noncommercial are attributed to their original Share Alike Creative authors. Commons license. 114

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