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Transcript

  • 1. Clues About EvolutionSection 2
  • 2. Clues FromFossils
  • 3. How do fossils form?
  • 4. How do fossils form?Fossilization - a variety of complex processes that preserve organic remains within the geological record.
  • 5. How do fossils form?Fossilization - a variety of complex processes that preserve organic remains within the geological record.It includes the following conditions:
  • 6. How do fossils form?Fossilization - a variety of complex processes that preserve organic remains within the geological record.It includes the following conditions: rapid and permanent burial/entombment protecting the specimen from environmental or biological disturbance
  • 7. How do fossils form?Fossilization - a variety of complex processes that preserve organic remains within the geological record.It includes the following conditions: rapid and permanent continued sediment burial/entombment accumulation as opposed to protecting the specimen an eroding surface from environmental or ensuring the organism remains biological disturbance buried in the long-term
  • 8. How do fossils form?Fossilization - a variety of complex processes that preserve organic remains within the geological record.It includes the following conditions: rapid and permanent continued sediment burial/entombment accumulation as opposed to protecting the specimen an eroding surface from environmental or ensuring the organism remains biological disturbance buried in the long-term oxygen deprivation limiting the extent of decay and also biological activity/scavenging
  • 9. How do fossils form?Fossilization - a variety of complex processes that preserve organic remains within the geological record.It includes the following conditions: rapid and permanent continued sediment burial/entombment accumulation as opposed to protecting the specimen an eroding surface from environmental or ensuring the organism remains biological disturbance buried in the long-term oxygen deprivation absence of excessive heating limiting the extent of or compression decay and also biological which might otherwise destroy activity/scavenging the remains
  • 10. How do fossils form?
  • 11. How do fossils form? Fossil evidence is typically preserved within sediments
  • 12. How do fossils form? Fossil evidence is typically preserved within sediments beneath water
  • 13. How do fossils form? Fossil evidence is typically preserved within sediments beneath water Why?
  • 14. How do fossils form? Fossil evidence is typically preserved within sediments beneath water Why?
  • 15. How do fossils form? Fossil evidence is typically preserved within sediments beneath water Why?The conditions listed on theprevious slide occur more frequentlybeneath water
  • 16. How do fossils form? Fossil evidence is typically preserved within sediments beneath water Why?The conditions listed on theprevious slide occur more frequentlybeneath water
  • 17. How do fossils form? Fossil evidence is typically preserved within sediments beneath water Why?The conditions The majority of listed on the the Earthsprevious slide surface is occur more covered by water frequently (70%+)beneath water
  • 18. How do fossils form? Fossil evidence is typically preserved within sediments beneath water Why?The conditions The majority of listed on the the Earthsprevious slide surface is occur more covered by water frequently (70%+)beneath water
  • 19. How do fossils form? Fossil evidence is typically preserved within sediments beneath water Why?The conditions The majority of Even fossils derived listed on the the Earths from land, includingprevious slide surface is dinosaur bones were occur more covered by water ultimately preserved frequently (70%+) in sedimentsbeneath water deposited beneath water
  • 20. How do fossils form?
  • 21. How do fossils form?
  • 22. How do fossils form? Fossilization can also occur on land, but is rare.
  • 23. How do fossils form? Fossilization can also occur on land, but is rare. How?
  • 24. How do fossils form? Fossilization can also occur on land, but is rare. How?
  • 25. How do fossils form? Fossilization can also occur on land, but is rare. How? specimens that undergo mummification in a cave or desert
  • 26. How do fossils form? Fossilization can also occur on land, but is rare. How? But... specimens that undergo mummification in a cave or desert
  • 27. How do fossils form? Fossilization can also occur on land, but is rare. How? But... specimens that undergo mummification in a cave or desert
  • 28. How do fossils form? Fossilization can also occur on land, but is rare. How? But... specimens that In reality these examples undergo are only a delay of mummification decomposition rather in a cave or than a lasting mode of desert fossilization
  • 29. A fish returns to its birth place to spawn.
  • 30. Having spawned the fish dies andshortly after sinks to the seafloor.
  • 31. After several weeks the soft body tissues have mostly decayed.
  • 32. Tectonic activity induces nearbysediment to mobilize, burying the fish in the event.
  • 33. Several months pass and all that remains of the buried fish is its skeleton.
  • 34. As times passes more sediment accumulates above the fish and theskeleton is gradually compressed and permineralized.
  • 35. Over time the rock is distorted anduplifted by geological forces associated with continental movement, raising it above sea level.
  • 36. The uplifted rock is exposed toweathering and gradually erodes away,eventually exposing the tip of the fishs skull at the surface.
  • 37. A paleontologist recognizes the fish by the small area of skull exposed and begins to carefully extract the specimen.
  • 38. A Pomognathus fish from HoughtonQuarry - the skull is clearly visible, and what parts of the skeleton remain are obscured within the chalk matrix.
  • 39. Types of FossilsMineralized Fossils Minerals replace wood or bone to create a piece of petrified wood or mineralized bone fossil.
  • 40. Types of FossilsImprint Fossil A leaf, feather, bone or entire body can leave an imprint on sediment that later hardens to become rock.
  • 41. Types of FossilsCast Fossil Minerals can fill in the hollows of animal tracks
  • 42. Types of FossilsFrozen Fossils The remains of an organism can be trapped in ice that remains frozen for thousands of years.  
  • 43. Types of FossilsFossil in Amber When the sticky resin of certain cone-bearing plants hardens over time, amber forms.
  • 44. Most fossils are found in sedimentary rocks.
  • 45. Most fossils are found in sedimentary rocks.Sedimentary rocks: formed when layers of sand, silt, clay, or mud are compacted and cemented together, or when minerals are deposited
  • 46. How Old?
  • 47. Paleontologists use two basic methods,either together or alone, to determine theage of a fossil:
  • 48. Paleontologists use two basic methods,either together or alone, to determine theage of a fossil:relative dating
  • 49. Paleontologists use two basic methods,either together or alone, to determine theage of a fossil:relative dating
  • 50. Paleontologists use two basic methods,either together or alone, to determine theage of a fossil:relative dating radiometric dating
  • 51. Paleontologists use two basic methods,either together or alone, to determine theage of a fossil:relative dating radiometric dating
  • 52. relative dating
  • 53. based on the idea that inrelative dating undisturbed areas, younger rock layers are deposited on top of older rock layers.
  • 54. based on the idea that inrelative dating undisturbed areas, younger rock layers are deposited on top of older rock layers. provides only an estimate of a fossil’s age
  • 55. based on the idea that inrelative dating undisturbed areas, younger rock layers are deposited on top of older rock layers. provides only an estimate of a fossil’s age estimate is made by comparing the ages of rock layers above and below the fossil layer
  • 56. radioactive elements give off a steady amount of radiation as it slowlychanges to a nonradioactive element
  • 57. radioactive elements give off a steady amount of radiation as it slowlychanges to a nonradioactive elementthe age is estimated by comparingthe amount of radioactive elementwith the amount of nonradioactive element in the rock
  • 58. radioactive elements give off a steady amount of radiation as it slowlychanges to a nonradioactive elementthe age is estimated by comparingthe amount of radioactive elementwith the amount of nonradioactive element in the rock this method does not alwaysproduce exact results, because the original amounts of radioactive element in the rock can never be determined
  • 59. radiometric radioactive elements give off a steady amount of dating radiation as it slowly changes to a nonradioactive element the age is estimated by comparing the amount of radioactive element with the amount of nonradioactive element in the rock this method does not always produce exact results, because the original amounts of radioactive element in the rock can never be determined
  • 60. Radioactive Decayan unstable nucleus loses energy by emittingionizing particles and radiation. Carbon 14
  • 61. Radioactive Decayan unstable nucleus loses energy by emittingionizing particles and radiation. Carbon 14 6 protons 8 electrons trace amounts on Earth – less than 1 ppt (0.0000000001%)
  • 62. Radioactive Decayan unstable nucleus loses energy by emittingionizing particles and radiation. Carbon 14 6 protons 8 electrons trace amounts on Earth – less than 1 ppt (0.0000000001%)
  • 63. Radioactive Decayan unstable nucleus loses energy by emittingionizing particles and radiation. Carbon 14 6 protons 8 electrons trace amounts on Earth – less than 1 ppt (0.0000000001%)
  • 64. Radioactive DecayThis decay, or loss of energy, results in anatom of one type transforming to an atom ofa different type. Carbon 14 6 protons 8 electrons trace amounts on Earth – less than 1 ppt (0.0000000001%)
  • 65. Half life of carbon-14 is 5,730 ± 40 years. It can only accurately measure up to 60,000 years.
  • 66. Half life of carbon-14 is 5,730 ± 40 years. It can only accurately measure up to 60,000 years.The method of dating does not always produce exact results, because the original amount of radioactive element in the rock can never be determined for certain.
  • 67. Fossils and Evolution
  • 68. Fossils and EvolutionFossils provide a record of organisms that lived in the past.
  • 69. Fossils and EvolutionFossils provide a record of organisms that lived in the past.However, the fossil record is incomplete, it has gaps.
  • 70. Fossils and EvolutionFossils provide a record of organisms that lived in the past.However, the fossil record is incomplete, it has gaps.The gaps exist because most organisms do not become fossils.
  • 71. Green Egg and Ham I am Sam  Would you like them Sam I am Here or there? That Sam-I-am I would not like them That Sam-I-am! here or there. I do not like I would not like them that Sam-I-am anywhere. I do not like Do you like green eggs and ham. green eggs and ham I do not like them, Sam-I-am I do not like them, Would you like them Sam-I-am. in a house? I do not like Would you like them green eggs and ham. with a mouse? .
  • 72. Fossils and Models
  • 73. Fossils and ModelsScientists can use fossils to make models that show what the organisms might have looked like.
  • 74. Fossils and ModelsScientists can use fossils to make models that show what the organisms might have looked like.From fossils, scientists can sometimes determine whether the organisms lived in family groups or alone what types of food they ate what kind of environment they lived in
  • 75. Direct Evidence for Evolution
  • 76. Direct Evidence for EvolutionPlant breeders observe evolution when they use cross-breeding to produce genetic changes in plants.
  • 77. Direct Evidence for EvolutionPlant breeders observe evolution when they use cross-breeding to produce genetic changes in plants.The development of antibiotic resistance in bacteria is another direct observation of evolution.
  • 78. Direct Evidence for EvolutionPlant breeders observe evolution when they use cross-breeding to produce genetic changes in plants.The development of antibiotic resistance in bacteria is another direct observation of evolution.Scientists have noted similar rapid evolution of pesticide-resistant insect species.
  • 79. Indirect Evidence for Evolution
  • 80. Indirect Evidence for EvolutionSimilarities in embryo structures
  • 81. Indirect Evidence for EvolutionSimilarities in embryo structuresChemical makeup of organisms including DNA the way organisms develop into adults
  • 82. Indirect Evidence for EvolutionSimilarities in embryo structuresChemical makeup of organisms including DNA the way organisms develop into adultsIndirect evidence does not provide proof of evolution, but it does support the idea.
  • 83. Embryology
  • 84. EmbryologyThe study of embryos and their development.
  • 85. EmbryologyThe study of embryos and their development.A tail and pharyngeal pouches are found at some point in the embryos of fish, reptiles, birds, and mammals.
  • 86. EmbryologyThe study of embryos and their development.A tail and pharyngeal pouches are found at some point in the embryos of fish, reptiles, birds, and mammals.Fish develop gills, but the other organisms develop other structures.
  • 87. EmbryologyThe study of embryos and their development.A tail and pharyngeal pouches are found at some point in the embryos of fish, reptiles, birds, and mammals.Fish develop gills, but the other organisms develop other structures.Fish, birds, and reptiles keep their tails, but many mammals lose theirs.
  • 88. EmbryologyThe study of embryos and their development.A tail and pharyngeal pouches are found at some point in the embryos of fish, reptiles, birds, and mammals.Fish develop gills, but the other organisms develop other structures.Fish, birds, and reptiles keep their tails, but many mammals lose theirs.These similarities suggest an evolutionary relationship among all vertebrate species.
  • 89. Homologous Structures
  • 90. Homologous StructuresBody parts that are similar in origin and structure are called homologous. They can also be similar in function.
  • 91. Homologous StructuresBody parts that are similar in origin and structure are called homologous. They can also be similar in function.They often indicate that two or more species share common ancestors.
  • 92. Vestigial Structures
  • 93. Vestigial StructuresVestigial structures —structures that don’t seem to have a function.
  • 94. Vestigial StructuresVestigial structures —structures that don’t seem to have a function.Vestigial structures also provide evidence for evolution.
  • 95. Vestigial StructuresVestigial structures —structures that don’t seem to have a function.Vestigial structures also provide evidence for evolution.Scientists hypothesize that vestigial structures are body parts that once functioned in an ancestor.
  • 96. Vestigial StructuresVestigial structures —structures that don’t seem to have a function.Vestigial structures also provide evidence for evolution.Scientists hypothesize that vestigial structures are body parts that once functioned in an ancestor.Appendix
  • 97. Our Appendix ~ Useful afterThe US scientists This function has been made obsolete by modern,found that the industrialised society; populations are now soappendix acted as a dense that people pick up essential bacteria from"good safe house" for each other, allowing gut organisms to regrowbacteria essential for without help from the appendix, the researchershealthy digestion, in said.effect re-booting the But in earlier centuries, when vast tracts of landdigestive system after were more sparsely populated and whole regionsthe host has could be wiped out by an epidemic of cholera, thecontracted diseases appendix provided survivors with a vital individualsuch as amoebic stockpile of suitable bacteria.dysentery or cholera, "The function of the appendix seems related to thewhich kill off helpful massive amount of bacteria that populates thegerms and purge the human digestive system," said Bill Parker, agut. professor of surgery and one of the scientists responsible for establishing its status as a useful http://www.independent.co.uk/life-style/health-and-families/health-news/the-appendix-does-have-a-use--rebooting-the-gut-396277.
  • 98. DNA
  • 99. DNAScientists compare DNA from living organisms to identify similarities among species.
  • 100. DNAScientists compare DNA from living organisms to identify similarities among species.Examinations of ancient DNA often provide additional evidence of how some species evolved from their extinct ancestors.
  • 101. DNAScientists compare DNA from living organisms to identify similarities among species.Examinations of ancient DNA often provide additional evidence of how some species evolved from their extinct ancestors.By looking at DNA, scientists also can determine how closely related organisms are.
  • 102. DNAScientists compare DNA from living organisms to identify similarities among species.Examinations of ancient DNA often provide additional evidence of how some species evolved from their extinct ancestors.By looking at DNA, scientists also can determine how closely related organisms are.For example, DNA studies indicate that dogs are the closest relatives of bears.