AIM:
How can we know that evolution has
        actually occurred?
             Warm – up:
      How does Darwin explain t...
LaMarck
• Organisms adapted to their environments
  ØThrough acquired traits
  ØChange in their lifetime
    v Use & Disus...
LaMarck
• Organisms adapted to their environments
  ØThrough acquired traits
  ØChange in their lifetime
    v Use & Disus...
But the fossil record shows…
Descent with Modification

Darwin’s idea that each species living
  today arose from a pre-existing
               species!
Hundreds of millions of years passed before atmospheric
oxygen levels were high enough to support eukaryotes.
Evidence Supporting Evolution
Evidence Supporting Evolution
• Fossils (descent with modification)
Evidence Supporting Evolution
• Fossils (descent with modification)
• Comparative biochemistry
Evidence Supporting Evolution
• Fossils (descent with modification)
• Comparative biochemistry
• Comparative cell biology
Evidence Supporting Evolution
•   Fossils (descent with modification)
•   Comparative biochemistry
•   Comparative cell bi...
Evidence Supporting Evolution
•   Fossils (descent with modification)
•   Comparative biochemistry
•   Comparative cell bi...
Fossils as Evidence
Fossils as Evidence
• A fossil is the remains of organisms that
  lived in the past.
Fossils as Evidence
• A fossil is the remains of organisms that
  lived in the past.
• They are preserved by natural proce...
Fossils as Evidence
• A fossil is the remains of organisms that
  lived in the past.
• They are preserved by natural proce...
Fossils as Evidence
• A fossil is the remains of organisms that
  lived in the past.
• They are preserved by natural proce...
How old are fossils?
How old are fossils?
• Relative dating: Fossils can be dated in
  correlation with the age of the strata (layer
  of rock)...
How old are fossils?
• Relative dating: Fossils can be dated in
  correlation with the age of the strata (layer
  of rock)...
Problems with Fossils?
Problems with Fossils?
• Dating is only an approximation
Problems with Fossils?
• Dating is only an approximation
• No fossils of early or soft-bodied
  organisms
Problems with Fossils?
• Dating is only an approximation
• No fossils of early or soft-bodied
  organisms
• Holes in the f...
Problems with Fossils?
• Dating is only an approximation
• No fossils of early or soft-bodied
  organisms
• Holes in the f...
Problems with Fossils?
• Dating is only an approximation
• No fossils of early or soft-bodied
  organisms
• Holes in the f...
Land Mammal



?
    ?
        ?
        ?
Land Mammal



          ?
              ?
           e the ?
      re ar tes?
Whe edia         ?
In term
Land Mammal



          ?
              ?
           e the ?
      re ar tes?
Whe edia         ?
In term
Land Mammal



          ?
              ?
           e the ?
      re ar tes?
Whe edia         ?
In term
Land Mammal
2006 Fossil Discovery of Early
             Tetrapod
• Missing link from sea to land animals
2006 Fossil Discovery of Early
             Tetrapod
• Missing link from sea to land animals
Comparative Biochemistry &
 Cell Biology show that…
Comparative Biochemistry &
     Cell Biology show that…
• the genetic code in nucleic acids is almost
  universal
Comparative Biochemistry &
     Cell Biology show that…
• the genetic code in nucleic acids is almost
  universal
• physio...
Comparative Biochemistry &
     Cell Biology show that…
• the genetic code in nucleic acids is almost
  universal
• physio...
Comparative Biochemistry &
     Cell Biology show that…
• the genetic code in nucleic acids is almost
  universal
• physio...
Comparative Biochemistry &
     Cell Biology show that…
• the genetic code in nucleic acids is almost
  universal
• physio...
Comparative Biochemistry &
     Cell Biology show that…
• the genetic code in nucleic acids is almost
  universal
• physio...
Comparative Biochemistry &
     Cell Biology show that…
• the genetic code in nucleic acids is almost
  universal
• physio...
Comparative Biochemistry &
     Cell Biology show that…
• the genetic code in nucleic acids is almost
  universal
• physio...
Comparative Embryology
Comparative Embryology
• Species that are known to be closely
  related show similar embryonic
  development.
Comparative Embryology
• Species that are known to be closely
  related show similar embryonic
  development.
• Inference:...
Comparative Anatomy
Comparative Anatomy
• Study of biological structures in different organisms
Comparative Anatomy
• Study of biological structures in different organisms
Comparative Anatomy
• Study of biological structures in different organisms

• Homologous structures: structures in differ...
Comparative Anatomy
• Study of biological structures in different organisms

• Homologous structures: structures in differ...
Comparative Anatomy
• Study of biological structures in different organisms

• Homologous structures: structures in differ...
Comparative Anatomy
• Study of biological structures in different organisms

• Homologous structures: structures in differ...
Comparative Anatomy
• Study of biological structures in different organisms

• Homologous structures: structures in differ...
Analogous structures
Analogous structures
Analogous structures
• Separate evolution of structures
Analogous structures
• Separate evolution of structures
  – similar functions
Analogous structures
• Separate evolution of structures
  – similar functions
  – similar external form
Analogous structures
• Separate evolution of structures
  – similar functions
  – similar external form
  – different inte...
Analogous structures
• Separate evolution of structures
  – similar functions
  – similar external form
  – different inte...
Analogous structures
• Separate evolution of structures
  – similar functions
  – similar external form
  – different inte...
Analogous structures
• Separate evolution of structures
  – similar functions
  – similar external form
  – different inte...
Analogous structures
• Separate evolution of structures
  – similar functions
  – similar external form
  – different inte...
Vestigial Structures
Vestigial Structures
• Modern animals may have structures that
  serve little or no function
Vestigial Structures
• Modern animals may have structures that
  serve little or no function
  – remnants of structures th...
Vestigial Structures
• Modern animals may have structures that
  serve little or no function
  – remnants of structures th...
Vestigial Structures
• Modern animals may have structures that
  serve little or no function
  – remnants of structures th...
Vestigial Structures
• Modern animals may have structures that
  serve little or no function
  – remnants of structures th...
Vestigial Structures
• Modern animals may have structures that
  serve little or no function
  – remnants of structures th...
Vestigial Structures
• Modern animals may have structures that
  serve little or no function
  – remnants of structures th...
Vestigial Structures
• Modern animals may have structures that
  serve little or no function
  – remnants of structures th...
Vestigial Structures
• Hind leg bones on whale fossils
Vestigial Structures
• Hind leg bones on whale fossils
Vestigial Structures
• Hind leg bones on whale fossils



     Why would whales
   have pelvis & leg bones
    if they wer...
ANY QUESTIONS??
 This is the time to ask…
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1.2

  1. 1. AIM: How can we know that evolution has actually occurred? Warm – up: How does Darwin explain the presence of organisms alive today?
  2. 2. LaMarck • Organisms adapted to their environments ØThrough acquired traits ØChange in their lifetime v Use & Disuse: organisms lost parts of their body because they did not use them (like the missing eyes and digestive system of the tapeworm) v Perfection with Use & Need: the constant use of an organ leads to an increase in size of that organ ØTransmit acquired characteristics to next generation
  3. 3. LaMarck • Organisms adapted to their environments ØThrough acquired traits ØChange in their lifetime v Use & Disuse: organisms lost parts of their body because they did not use them (like the missing eyes and digestive system of the tapeworm) v Perfection with Use & Need: the constant use of an organ leads to an increase in size of that organ ØTransmit acquired characteristics to next generation
  4. 4. But the fossil record shows…
  5. 5. Descent with Modification Darwin’s idea that each species living today arose from a pre-existing species!
  6. 6. Hundreds of millions of years passed before atmospheric oxygen levels were high enough to support eukaryotes.
  7. 7. Evidence Supporting Evolution
  8. 8. Evidence Supporting Evolution • Fossils (descent with modification)
  9. 9. Evidence Supporting Evolution • Fossils (descent with modification) • Comparative biochemistry
  10. 10. Evidence Supporting Evolution • Fossils (descent with modification) • Comparative biochemistry • Comparative cell biology
  11. 11. Evidence Supporting Evolution • Fossils (descent with modification) • Comparative biochemistry • Comparative cell biology • Comparative embryology
  12. 12. Evidence Supporting Evolution • Fossils (descent with modification) • Comparative biochemistry • Comparative cell biology • Comparative embryology • Comparative anatomy
  13. 13. Fossils as Evidence
  14. 14. Fossils as Evidence • A fossil is the remains of organisms that lived in the past.
  15. 15. Fossils as Evidence • A fossil is the remains of organisms that lived in the past. • They are preserved by natural processes (in ice, rock, etc.)
  16. 16. Fossils as Evidence • A fossil is the remains of organisms that lived in the past. • They are preserved by natural processes (in ice, rock, etc.) • Examples: bones, shells, footprints, imprints
  17. 17. Fossils as Evidence • A fossil is the remains of organisms that lived in the past. • They are preserved by natural processes (in ice, rock, etc.) • Examples: bones, shells, footprints, imprints • Generally, found in sedimentary rock that has been quickly covered by silt. Why?
  18. 18. How old are fossils?
  19. 19. How old are fossils? • Relative dating: Fossils can be dated in correlation with the age of the strata (layer of rock) they are in.
  20. 20. How old are fossils? • Relative dating: Fossils can be dated in correlation with the age of the strata (layer of rock) they are in. • Absolute Dating: Using radioactive isotopes (half life) to get a more accurate estimate of age.
  21. 21. Problems with Fossils?
  22. 22. Problems with Fossils? • Dating is only an approximation
  23. 23. Problems with Fossils? • Dating is only an approximation • No fossils of early or soft-bodied organisms
  24. 24. Problems with Fossils? • Dating is only an approximation • No fossils of early or soft-bodied organisms • Holes in the fossil record
  25. 25. Problems with Fossils? • Dating is only an approximation • No fossils of early or soft-bodied organisms • Holes in the fossil record
  26. 26. Problems with Fossils? • Dating is only an approximation • No fossils of early or soft-bodied organisms • Holes in the fossil record So what do scientists turn to?
  27. 27. Land Mammal ? ? ? ?
  28. 28. Land Mammal ? ? e the ? re ar tes? Whe edia ? In term
  29. 29. Land Mammal ? ? e the ? re ar tes? Whe edia ? In term
  30. 30. Land Mammal ? ? e the ? re ar tes? Whe edia ? In term
  31. 31. Land Mammal
  32. 32. 2006 Fossil Discovery of Early Tetrapod • Missing link from sea to land animals
  33. 33. 2006 Fossil Discovery of Early Tetrapod • Missing link from sea to land animals
  34. 34. Comparative Biochemistry & Cell Biology show that…
  35. 35. Comparative Biochemistry & Cell Biology show that… • the genetic code in nucleic acids is almost universal
  36. 36. Comparative Biochemistry & Cell Biology show that… • the genetic code in nucleic acids is almost universal • physiological processes follow common metabolic pathways
  37. 37. Comparative Biochemistry & Cell Biology show that… • the genetic code in nucleic acids is almost universal • physiological processes follow common metabolic pathways • ATP is the universal form of energy
  38. 38. Comparative Biochemistry & Cell Biology show that… • the genetic code in nucleic acids is almost universal • physiological processes follow common metabolic pathways • ATP is the universal form of energy • Organisms that are related often have similar types of proteins and antibodies
  39. 39. Comparative Biochemistry & Cell Biology show that… • the genetic code in nucleic acids is almost universal • physiological processes follow common metabolic pathways • ATP is the universal form of energy • Organisms that are related often have similar types of proteins and antibodies
  40. 40. Comparative Biochemistry & Cell Biology show that… • the genetic code in nucleic acids is almost universal • physiological processes follow common metabolic pathways • ATP is the universal form of energy • Organisms that are related often have similar types of proteins and antibodies
  41. 41. Comparative Biochemistry & Cell Biology show that… • the genetic code in nucleic acids is almost universal • physiological processes follow common metabolic pathways • ATP is the universal form of energy • Organisms that are related often have similar types of proteins and antibodies
  42. 42. Comparative Biochemistry & Cell Biology show that… • the genetic code in nucleic acids is almost universal • physiological processes follow common metabolic pathways • ATP is the universal form of energy • Organisms that are related often have similar types of proteins and antibodies
  43. 43. Comparative Embryology
  44. 44. Comparative Embryology • Species that are known to be closely related show similar embryonic development.
  45. 45. Comparative Embryology • Species that are known to be closely related show similar embryonic development. • Inference: The longer two embryos stay looking similar, the more closely related they are.
  46. 46. Comparative Anatomy
  47. 47. Comparative Anatomy • Study of biological structures in different organisms
  48. 48. Comparative Anatomy • Study of biological structures in different organisms
  49. 49. Comparative Anatomy • Study of biological structures in different organisms • Homologous structures: structures in different species that have a similar design and position but serve different purposes in species that live in different environments.
  50. 50. Comparative Anatomy • Study of biological structures in different organisms • Homologous structures: structures in different species that have a similar design and position but serve different purposes in species that live in different environments. ex. Pentadactyl limb in mammals
  51. 51. Comparative Anatomy • Study of biological structures in different organisms • Homologous structures: structures in different species that have a similar design and position but serve different purposes in species that live in different environments. ex. Pentadactyl limb in mammals • Divergent evolution
  52. 52. Comparative Anatomy • Study of biological structures in different organisms • Homologous structures: structures in different species that have a similar design and position but serve different purposes in species that live in different environments. ex. Pentadactyl limb in mammals • Divergent evolution
  53. 53. Comparative Anatomy • Study of biological structures in different organisms • Homologous structures: structures in different species that have a similar design and position but serve different purposes in species that live in different environments. ex. Pentadactyl limb in mammals • Divergent evolution • Analogous structures: Structure of two unrelated species that can evolve to look alike on the basis that they serve a similar function in a similar environment.
  54. 54. Analogous structures
  55. 55. Analogous structures
  56. 56. Analogous structures • Separate evolution of structures
  57. 57. Analogous structures • Separate evolution of structures – similar functions
  58. 58. Analogous structures • Separate evolution of structures – similar functions – similar external form
  59. 59. Analogous structures • Separate evolution of structures – similar functions – similar external form – different internal structure & development
  60. 60. Analogous structures • Separate evolution of structures – similar functions – similar external form – different internal structure & development – different origin
  61. 61. Analogous structures • Separate evolution of structures – similar functions – similar external form – different internal structure & development – different origin – no evolutionary relationship
  62. 62. Analogous structures • Separate evolution of structures – similar functions – similar external form – different internal structure & development – different origin – no evolutionary relationship Solving a similar problem with a similar solution
  63. 63. Analogous structures • Separate evolution of structures – similar functions – similar external form – different internal structure & development – different origin – no evolutionary relationship Don’t be fooled by their looks! Solving a similar problem with a similar solution
  64. 64. Vestigial Structures
  65. 65. Vestigial Structures • Modern animals may have structures that serve little or no function
  66. 66. Vestigial Structures • Modern animals may have structures that serve little or no function – remnants of structures that were functional in ancestral species
  67. 67. Vestigial Structures • Modern animals may have structures that serve little or no function – remnants of structures that were functional in ancestral species – evidence of change over time
  68. 68. Vestigial Structures • Modern animals may have structures that serve little or no function – remnants of structures that were functional in ancestral species – evidence of change over time • some snakes & whales
  69. 69. Vestigial Structures • Modern animals may have structures that serve little or no function – remnants of structures that were functional in ancestral species – evidence of change over time • some snakes & whales show remains of the
  70. 70. Vestigial Structures • Modern animals may have structures that serve little or no function – remnants of structures that were functional in ancestral species – evidence of change over time • some snakes & whales show remains of the pelvis & leg bones of
  71. 71. Vestigial Structures • Modern animals may have structures that serve little or no function – remnants of structures that were functional in ancestral species – evidence of change over time • some snakes & whales show remains of the pelvis & leg bones of walking ancestors
  72. 72. Vestigial Structures • Modern animals may have structures that serve little or no function – remnants of structures that were functional in ancestral species – evidence of change over time • some snakes & whales show remains of the pelvis & leg bones of walking ancestors • human tail bone
  73. 73. Vestigial Structures • Hind leg bones on whale fossils
  74. 74. Vestigial Structures • Hind leg bones on whale fossils
  75. 75. Vestigial Structures • Hind leg bones on whale fossils Why would whales have pelvis & leg bones if they were always sea creatures?
  76. 76. ANY QUESTIONS?? This is the time to ask…
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