OHHS AP Bio Chapter 25 Presentation

8,112 views

Published on

Chapter 25 complete presentation.

Published in: Education
0 Comments
8 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
8,112
On SlideShare
0
From Embeds
0
Number of Embeds
19
Actions
Shares
0
Downloads
221
Comments
0
Likes
8
Embeds 0
No embeds

No notes for slide
  • Figure 25.1 What does fossil evidence say about where these dinosaurs lived?
  • Figure 25.2 A window to early life?
  • Figure 25.3 Laboratory versions of protobionts
  • Figure 25.3 Laboratory versions of protobionts
  • Figure 25.3 Laboratory versions of protobionts
  • Figure 25.4 Documenting the history of life
  • Figure 25.4 Documenting the history of life
  • Figure 25.4 Documenting the history of life
  • Figure 25.4 Documenting the history of life
  • Figure 25.4 Documenting the history of life
  • Figure 25.4 Documenting the history of life
  • Figure 25.4 Documenting the history of life
  • Figure 25.4 Documenting the history of life
  • Figure 25.4 Documenting the history of life
  • Figure 25.4 Documenting the history of life
  • Figure 25.4 Documenting the history of life
  • Figure 25.4 Documenting the history of life
  • Figure 25.5 Radiometric dating
  • Figure 25.6 The origin of mammals
  • Figure 25.6 The origin of mammals
  • Figure 25.6 The origin of mammals
  • Table 25.1
  • Table 25.1
  • Table 25.1
  • Figure 25.7 Clock analogy for some key events in Earth’s history
  • Figure 25.8 Banded iron formations: evidence of oxygenic photosynthesis For the Discovery Video Early Life, go to Animation and Video Files.
  • Figure 25.9 A model of the origin of eukaryotes through serial endosymbiosis
  • Figure 25.9 A model of the origin of eukaryotes through serial endosymbiosis
  • Figure 25.9 A model of the origin of eukaryotes through serial endosymbiosis
  • Figure 25.9 A model of the origin of eukaryotes through serial endosymbiosis
  • Figure 25.10 Appearance of selected animal phyla
  • Figure 25.11 Proterozoic fossils that may be animal embryos (SEM)
  • Figure 25.12 Earth and its continental plates
  • Figure 25.12 Earth and its continental plates
  • Figure 25.12 Earth and its continental plates
  • Figure 25.13 The history of continental drift during the Phanerozoic eon
  • Figure 25.13 The history of continental drift during the Phanerozoic eon
  • Figure 25.13 The history of continental drift during the Phanerozoic eon
  • Figure 25.14 Mass extinction and the diversity of life
  • Figure 25.15 Trauma for Earth and its Cretaceous life For the Discovery Video Mass Extinctions, go to Animation and Video Files.
  • Figure 25.16 Mass extinctions and ecology
  • Figure 25.17 Adaptive radiation of mammals
  • Figure 25.18 Adaptive radiation on the Hawaiian Islands
  • Figure 25.18 Adaptive radiation on the Hawaiian Islands
  • Figure 25.18 Adaptive radiation on the Hawaiian Islands
  • Figure 25.18 Adaptive radiation on the Hawaiian Islands
  • Figure 25.18 Adaptive radiation on the Hawaiian Islands
  • Figure 25.18 Adaptive radiation on the Hawaiian Islands
  • Figure 25.18 Adaptive radiation on the Hawaiian Islands
  • Figure 25.18 Adaptive radiation on the Hawaiian Islands
  • Figure 25.19 Relative growth rates of body parts
  • Figure 25.19 Relative growth rates of body parts
  • Figure 25.19 Relative growth rates of body parts
  • Figure 25.20 Paedomorphosis
  • Figure 25.21 Hox mutations and the origin of vertebrates
  • Figure 25.22 Origin of the insect body plan
  • Figure 25.23 What causes the loss of spines in lake stickleback fish?
  • Figure 25.23 What causes the loss of spines in lake stickleback fish?
  • Figure 25.24 A range of eye complexity among molluscs
  • Figure 25.25 The branched evolution of horses
  • Figure 25.25 The branched evolution of horses
  • Figure 25.25 The branched evolution of horses
  • OHHS AP Bio Chapter 25 Presentation

    1. 1. Chapter 25 The History of Life on Earth
    2. 2. Overview: Lost Worlds <ul><li>Past organisms were very different from those now alive </li></ul><ul><li>The fossil record shows macroevolutionary changes over large time scales including </li></ul><ul><ul><li>The emergence of terrestrial vertebrates </li></ul></ul><ul><ul><li>The origin of photosynthesis </li></ul></ul><ul><ul><li>Long-term impacts of mass extinctions </li></ul></ul>
    3. 3. Fig. 25-1
    4. 4. Fig 25-UN1 Cryolophosaurus
    5. 5. Concept 25.1: Conditions on early Earth made the origin of life possible <ul><li>Chemical and physical processes on early Earth may have produced very simple cells through a sequence of stages: </li></ul><ul><ul><li>1. Abiotic synthesis of small organic molecules </li></ul></ul><ul><ul><li>2. Joining of these small molecules into macromolecules </li></ul></ul><ul><ul><li>3. Packaging of molecules into “protobionts” </li></ul></ul><ul><ul><li>4. Origin of self-replicating molecules </li></ul></ul>
    6. 6. Synthesis of Organic Compounds on Early Earth <ul><li>Earth formed about 4.6 billion years ago, along with the rest of the solar system </li></ul><ul><li>Earth’s early atmosphere likely contained water vapor and chemicals released by volcanic eruptions (nitrogen, nitrogen oxides, carbon dioxide, methane, ammonia, hydrogen, hydrogen sulfide) </li></ul>
    7. 7. <ul><li>A. I. Oparin and J. B. S. Haldane hypothesized that the early atmosphere was a reducing environment </li></ul><ul><li>Stanley Miller and Harold Urey conducted lab experiments that showed that the abiotic synthesis of organic molecules in a reducing atmosphere is possible </li></ul>
    8. 8. <ul><li>However, the evidence is not yet convincing that the early atmosphere was in fact reducing </li></ul><ul><li>Instead of forming in the atmosphere, the first organic compounds may have been synthesized near submerged volcanoes and deep-sea vents </li></ul>Video: Hydrothermal Vent Video: Tubeworms
    9. 9. Fig. 25-2
    10. 10. <ul><li>Amino acids have also been found in meteorites </li></ul>
    11. 11. Abiotic Synthesis of Macromolecules <ul><li>Small organic molecules polymerize when they are concentrated on hot sand, clay, or rock </li></ul>
    12. 12. Protobionts <ul><li>Replication and metabolism are key properties of life </li></ul><ul><li>Protobionts are aggregates of abiotically produced molecules surrounded by a membrane or membrane-like structure </li></ul><ul><li>Protobionts exhibit simple reproduction and metabolism and maintain an internal chemical environment </li></ul>
    13. 13. <ul><li>Experiments demonstrate that protobionts could have formed spontaneously from abiotically produced organic compounds </li></ul><ul><li>For example, small membrane-bounded droplets called liposomes can form when lipids or other organic molecules are added to water </li></ul>
    14. 14. Fig. 25-3 (a) Simple reproduction by liposomes (b) Simple metabolism Phosphate Maltose Phosphatase Maltose Amylase Starch Glucose-phosphate Glucose-phosphate 20 µm
    15. 15. Fig. 25-3a (a) Simple reproduction by liposomes 20 µm
    16. 16. Fig. 25-3b (b) Simple metabolism Phosphate Maltose Phosphatase Maltose Amylase Starch Glucose-phosphate Glucose-phosphate
    17. 17. Self-Replicating RNA and the Dawn of Natural Selection <ul><li>The first genetic material was probably RNA, not DNA </li></ul><ul><li>RNA molecules called ribozymes have been found to catalyze many different reactions </li></ul><ul><ul><li>For example, ribozymes can make complementary copies of short stretches of their own sequence or other short pieces of RNA </li></ul></ul>
    18. 18. <ul><li>Early protobionts with self-replicating, catalytic RNA would have been more effective at using resources and would have increased in number through natural selection </li></ul><ul><li>The early genetic material might have formed an “RNA world” </li></ul>
    19. 19. Concept 25.2: The fossil record documents the history of life <ul><li>The fossil record reveals changes in the history of life on earth </li></ul>
    20. 20. The Fossil Record <ul><li>Sedimentary rocks are deposited into layers called strata and are the richest source of fossils </li></ul>Video: Grand Canyon
    21. 21. Fig. 25-4 Present Dimetrodon Coccosteus cuspidatus Fossilized stromatolite Stromatolites Tappania, a unicellular eukaryote Dickinsonia costata Hallucigenia Casts of ammonites Rhomaleosaurus victor, a plesiosaur 100 million years ago 200 175 300 270 400 375 500 525 565 600 3,500 1,500 2.5 cm 4.5 cm 1 cm
    22. 22. Fig. 25-4-1 Fossilized stromatolite Stromatolites Tappania, a unicellular eukaryote Dickinsonia costata Hallucigenia 500 525 565 600 3,500 1,500 2.5 cm 4.5 cm 1 cm
    23. 23. Fig. 25-4a-2 Present Dimetrodon Coccosteus cuspidatus Casts of ammonites Rhomaleosaurus victor, a plesiosaur 100 million years ago 200 175 300 270 400 375 4.5 cm
    24. 24. Fig. 25-4b Rhomaleosaurus victor, a plesiosaur
    25. 25. Fig. 25-4c Dimetrodon
    26. 26. Fig. 25-4d Casts of ammonites
    27. 27. Fig. 25-4e Coccosteus cuspidatus 4.5 cm
    28. 28. Fig. 25-4f Hallucigenia 1 cm
    29. 29. Fig. 25-4g Dickinsonia costata 2.5 cm
    30. 30. Fig. 25-4h Tappania, a unicellular eukaryote
    31. 31. Fig. 25-4i Stromatolites
    32. 32. Fig. 25-4j Fossilized stromatolite
    33. 33. <ul><li>Few individuals have fossilized, and even fewer have been discovered </li></ul><ul><li>The fossil record is biased in favor of species that </li></ul><ul><ul><li>Existed for a long time </li></ul></ul><ul><ul><li>Were abundant and widespread </li></ul></ul><ul><ul><li>Had hard parts </li></ul></ul>Animation: The Geologic Record
    34. 34. How Rocks and Fossils Are Dated <ul><li>Sedimentary strata reveal the relative ages of fossils </li></ul><ul><li>The absolute ages of fossils can be determined by radiometric dating </li></ul><ul><li>A “parent” isotope decays to a “daughter” isotope at a constant rate </li></ul><ul><li>Each isotope has a known half-life , the time required for half the parent isotope to decay </li></ul>
    35. 35. Fig. 25-5 Time (half-lives) Accumulating “ daughter” isotope Remaining “ parent” isotope Fraction of parent isotope remaining 1 2 3 4 1 / 2 1 / 4 1 / 8 1 / 16
    36. 36. <ul><li>Radiocarbon dating can be used to date fossils up to 75,000 years old </li></ul><ul><li>For older fossils, some isotopes can be used to date sedimentary rock layers above and below the fossil </li></ul>
    37. 37. <ul><li>The magnetism of rocks can provide dating information </li></ul><ul><li>Reversals of the magnetic poles leave their record on rocks throughout the world </li></ul>
    38. 38. The Origin of New Groups of Organisms <ul><li>Mammals belong to the group of animals called tetrapods </li></ul><ul><li>The evolution of unique mammalian features through gradual modifications can be traced from ancestral synapsids through the present </li></ul>
    39. 39. Fig. 25-6 Very late cynodont (195 mya) Later cynodont (220 mya) Early cynodont (260 mya) Therapsid (280 mya) Synapsid (300 mya) Temporal fenestra Temporal fenestra Temporal fenestra EARLY TETRAPODS Articular Key Quadrate Dentary Squamosal Reptiles (including dinosaurs and birds) Dimetrodon Very late cynodonts Mammals Synapsids Therapsids Earlier cynodonts
    40. 40. Fig. 25-6-1 Therapsid (280 mya) Synapsid (300 mya) Temporal fenestra Temporal fenestra Articular Key Quadrate Dentary Squamosal
    41. 41. Fig. 25-6-2 Very late cynodont (195 mya) Later cynodont (220 mya) Early cynodont (260 mya) Temporal fenestra Articular Key Quadrate Dentary Squamosal
    42. 42. <ul><li>The geologic record is divided into the Archaean, the Proterozoic, and the Phanerozoic eons </li></ul>Concept 25.3: Key events in life’s history include the origins of single-celled and multicelled organisms and the colonization of land
    43. 43. Table 25-1
    44. 44. Table 25-1a
    45. 45. Table 25-1b
    46. 46. <ul><li>The Phanerozoic encompasses multicellular eukaryotic life </li></ul><ul><li>The Phanerozoic is divided into three eras: the Paleozoic, Mesozoic, and Cenozoic </li></ul><ul><li>Major boundaries between geological divisions correspond to extinction events in the fossil record </li></ul>
    47. 47. Fig. 25-7 Animals Colonization of land Paleozoic Meso- zoic Humans Ceno- zoic Origin of solar system and Earth Prokaryotes Proterozoic Archaean Billions of years ago 1 4 3 2 Multicellular eukaryotes Single-celled eukaryotes Atmospheric oxygen
    48. 48. The First Single-Celled Organisms <ul><li>The oldest known fossils are stromatolites , rock-like structures composed of many layers of bacteria and sediment </li></ul><ul><li>Stromatolites date back 3.5 billion years ago </li></ul><ul><li>Prokaryotes were Earth’s sole inhabitants from 3.5 to about 2.1 billion years ago </li></ul>
    49. 49. Fig 25-UN2 Prokaryotes Billions of years ago 4 3 2 1
    50. 50. Photosynthesis and the Oxygen Revolution <ul><li>Most atmospheric oxygen (O 2 ) is of biological origin </li></ul><ul><li>O 2 produced by oxygenic photosynthesis reacted with dissolved iron and precipitated out to form banded iron formations </li></ul><ul><li>The source of O 2 was likely bacteria similar to modern cyanobacteria </li></ul>
    51. 51. <ul><li>By about 2.7 billion years ago, O 2 began accumulating in the atmosphere and rusting iron-rich terrestrial rocks </li></ul><ul><li>This “oxygen revolution” from 2.7 to 2.2 billion years ago </li></ul><ul><ul><li>Posed a challenge for life </li></ul></ul><ul><ul><li>Provided opportunity to gain energy from light </li></ul></ul><ul><ul><li>Allowed organisms to exploit new ecosystems </li></ul></ul>
    52. 52. Fig 25-UN3 Atmospheric oxygen Billions of years ago 4 3 2 1
    53. 53. Fig. 25-8
    54. 54. The First Eukaryotes <ul><li>The oldest fossils of eukaryotic cells date back 2.1 billion years </li></ul><ul><li>The hypothesis of endosymbiosis proposes that mitochondria and plastids (chloroplasts and related organelles) were formerly small prokaryotes living within larger host cells </li></ul><ul><li>An endosymbiont is a cell that lives within a host cell </li></ul>
    55. 55. Fig 25-UN4 Single- celled eukaryotes Billions of years ago 4 3 2 1
    56. 56. <ul><li>The prokaryotic ancestors of mitochondria and plastids probably gained entry to the host cell as undigested prey or internal parasites </li></ul><ul><li>In the process of becoming more interdependent, the host and endosymbionts would have become a single organism </li></ul><ul><li>Serial endosymbiosis supposes that mitochondria evolved before plastids through a sequence of endosymbiotic events </li></ul>
    57. 57. Fig. 25-9-1 Nucleus Cytoplasm DNA Plasma membrane Endoplasmic reticulum Nuclear envelope Ancestral prokaryote
    58. 58. Fig. 25-9-2 Aerobic heterotrophic prokaryote Mitochondrion Ancestral heterotrophic eukaryote
    59. 59. Fig. 25-9-3 Ancestral photosynthetic eukaryote Photosynthetic prokaryote Mitochondrion Plastid
    60. 60. Fig. 25-9-4 Ancestral photosynthetic eukaryote Photosynthetic prokaryote Mitochondrion Plastid Nucleus Cytoplasm DNA Plasma membrane Endoplasmic reticulum Nuclear envelope Ancestral prokaryote Aerobic heterotrophic prokaryote Mitochondrion Ancestral heterotrophic eukaryote
    61. 61. <ul><li>Key evidence supporting an endosymbiotic origin of mitochondria and plastids: </li></ul><ul><ul><li>Similarities in inner membrane structures and functions </li></ul></ul><ul><ul><li>Division is similar in these organelles and some prokaryotes </li></ul></ul><ul><ul><li>These organelles transcribe and translate their own DNA </li></ul></ul><ul><ul><li>Their ribosomes are more similar to prokaryotic than eukaryotic ribosomes </li></ul></ul>
    62. 62. The Origin of Multicellularity <ul><li>The evolution of eukaryotic cells allowed for a greater range of unicellular forms </li></ul><ul><li>A second wave of diversification occurred when multicellularity evolved and gave rise to algae, plants, fungi, and animals </li></ul>
    63. 63. The Earliest Multicellular Eukaryotes <ul><li>Comparisons of DNA sequences date the common ancestor of multicellular eukaryotes to 1.5 billion years ago </li></ul><ul><li>The oldest known fossils of multicellular eukaryotes are of small algae that lived about 1.2 billion years ago </li></ul>
    64. 64. <ul><li>The “snowball Earth” hypothesis suggests that periods of extreme glaciation confined life to the equatorial region or deep-sea vents from 750 to 580 million years ago </li></ul><ul><li>The Ediacaran biota were an assemblage of larger and more diverse soft-bodied organisms that lived from 565 to 535 million years ago </li></ul>
    65. 65. Fig 25-UN5 Multicellular eukaryotes Billions of years ago 4 3 2 1
    66. 66. The Cambrian Explosion <ul><li>The Cambrian explosion refers to the sudden appearance of fossils resembling modern phyla in the Cambrian period (535 to 525 million years ago) </li></ul><ul><li>The Cambrian explosion provides the first evidence of predator-prey interactions </li></ul>
    67. 67. Fig 25-UN6 Animals Billions of years ago 4 3 2 1
    68. 68. Fig. 25-10 Sponges Late Proterozoic eon Early Paleozoic era (Cambrian period) Cnidarians Annelids Brachiopods Echinoderms Chordates Millions of years ago 500 542 Arthropods Molluscs
    69. 69. <ul><li>DNA analyses suggest that many animal phyla diverged before the Cambrian explosion, perhaps as early as 700 million to 1 billion years ago </li></ul><ul><li>Fossils in China provide evidence of modern animal phyla tens of millions of years before the Cambrian explosion </li></ul><ul><li>The Chinese fossils suggest that “the Cambrian explosion had a long fuse” </li></ul>
    70. 70. Fig. 25-11 (a) Two-cell stage 150 µm 200 µm (b) Later stage
    71. 71. The Colonization of Land <ul><li>Fungi, plants, and animals began to colonize land about 500 million years ago </li></ul><ul><li>Plants and fungi likely colonized land together by 420 million years ago </li></ul><ul><li>Arthropods and tetrapods are the most widespread and diverse land animals </li></ul><ul><li>Tetrapods evolved from lobe-finned fishes around 365 million years ago </li></ul>
    72. 72. Fig 25-UN7 Colonization of land Billions of years ago 4 3 2 1
    73. 73. <ul><li>The history of life on Earth has seen the rise and fall of many groups of organisms </li></ul>Concept 25.4: The rise and fall of dominant groups reflect continental drift, mass extinctions, and adaptive radiations Video: Lava Flow Video: Volcanic Eruption
    74. 74. Continental Drift <ul><li>At three points in time, the land masses of Earth have formed a supercontinent: 1.1 billion, 600 million, and 250 million years ago </li></ul><ul><li>Earth’s continents move slowly over the underlying hot mantle through the process of continental drift </li></ul><ul><li>Oceanic and continental plates can collide, separate, or slide past each other </li></ul><ul><li>Interactions between plates cause the formation of mountains and islands, and earthquakes </li></ul>
    75. 75. Fig. 25-12 (a) Cutaway view of Earth (b) Major continental plates Inner core Outer core Crust Mantle Pacific Plate Nazca Plate Juan de Fuca Plate Cocos Plate Caribbean Plate Arabian Plate African Plate Scotia Plate North American Plate South American Plate Antarctic Plate Australian Plate Philippine Plate Indian Plate Eurasian Plate
    76. 76. Fig. 25-12a (a) Cutaway view of Earth Inner core Outer core Crust Mantle
    77. 77. Fig. 25-12b (b) Major continental plates Pacific Plate Nazca Plate Juan de Fuca Plate Cocos Plate Caribbean Plate Arabian Plate African Plate Scotia Plate North American Plate South American Plate Antarctic Plate Australian Plate Philippine Plate Indian Plate Eurasian Plate
    78. 78. Consequences of Continental Drift <ul><li>Formation of the supercontinent Pangaea about 250 million years ago had many effects </li></ul><ul><ul><li>A reduction in shallow water habitat </li></ul></ul><ul><ul><li>A colder and drier climate inland </li></ul></ul><ul><ul><li>Changes in climate as continents moved toward and away from the poles </li></ul></ul><ul><ul><li>Changes in ocean circulation patterns leading to global cooling </li></ul></ul>
    79. 79. Fig. 25-13 South America Pangaea Millions of years ago 65.5 135 Mesozoic 251 Paleozoic Gondwana Laurasia Eurasia India Africa Antarctica Australia North America Madagascar Cenozoic Present
    80. 80. Fig. 25-13a South America Millions of years ago 65.5 Eurasia India Africa Antarctica Australia North America Madagascar Cenozoic Present
    81. 81. Fig. 25-13b Pangaea Millions of years ago 135 Mesozoic 251 Paleozoic Gondwana Laurasia
    82. 82. <ul><li>The break-up of Pangaea lead to allopatric speciation </li></ul><ul><li>The current distribution of fossils reflects the movement of continental drift </li></ul><ul><li>For example, the similarity of fossils in parts of South America and Africa is consistent with the idea that these continents were formerly attached </li></ul>
    83. 83. Mass Extinctions <ul><li>The fossil record shows that most species that have ever lived are now extinct </li></ul><ul><li>At times, the rate of extinction has increased dramatically and caused a mass extinction </li></ul>
    84. 84. The “Big Five” Mass Extinction Events <ul><li>In each of the five mass extinction events, more than 50% of Earth’s species became extinct </li></ul>
    85. 85. Fig. 25-14 Total extinction rate (families per million years): Time (millions of years ago) Number of families: Cenozoic Mesozoic Paleozoic E O S D C P Tr J 542 0 488 444 416 359 299 251 200 145 Era Period 5 C P N 65.5 0 0 200 100 300 400 500 600 700 800 15 10 20
    86. 86. <ul><li>The Permian extinction defines the boundary between the Paleozoic and Mesozoic eras </li></ul><ul><li>This mass extinction occurred in less than 5 million years and caused the extinction of about 96% of marine animal species </li></ul><ul><li>This event might have been caused by volcanism, which lead to global warming, and a decrease in oceanic oxygen </li></ul>
    87. 87. <ul><li>The Cretaceous mass extinction 65.5 million years ago separates the Mesozoic from the Cenozoic </li></ul><ul><li>Organisms that went extinct include about half of all marine species and many terrestrial plants and animals, including most dinosaurs </li></ul>
    88. 88. Fig. 25-15 NORTH AMERICA Chicxulub crater Yucatán Peninsula
    89. 89. <ul><li>The presence of iridium in sedimentary rocks suggests a meteorite impact about 65 million years ago </li></ul><ul><li>The Chicxulub crater off the coast of Mexico is evidence of a meteorite that dates to the same time </li></ul>
    90. 90. Is a Sixth Mass Extinction Under Way? <ul><li>Scientists estimate that the current rate of extinction is 100 to 1,000 times the typical background rate </li></ul><ul><li>Data suggest that a sixth human-caused mass extinction is likely to occur unless dramatic action is taken </li></ul>
    91. 91. Consequences of Mass Extinctions <ul><li>Mass extinction can alter ecological communities and the niches available to organisms </li></ul><ul><li>It can take from 5 to 100 million years for diversity to recover following a mass extinction </li></ul><ul><li>Mass extinction can pave the way for adaptive radiations </li></ul>
    92. 92. Fig. 25-16 Predator genera (percentage of marine genera) Time (millions of years ago) Cenozoic Mesozoic Paleozoic E O S D C P Tr J 542 0 488 444 416 359 299 251 200 145 Era Period C P N 65.5 0 10 20 30 40 50
    93. 93. Adaptive Radiations <ul><li>Adaptive radiation is the evolution of diversely adapted species from a common ancestor upon introduction to new environmental opportunities </li></ul>
    94. 94. Worldwide Adaptive Radiations <ul><li>Mammals underwent an adaptive radiation after the extinction of terrestrial dinosaurs </li></ul><ul><li>The disappearance of dinosaurs (except birds) allowed for the expansion of mammals in diversity and size </li></ul><ul><li>Other notable radiations include photosynthetic prokaryotes, large predators in the Cambrian, land plants, insects, and tetrapods </li></ul>
    95. 95. Fig. 25-17 Millions of years ago Monotremes (5 species) 250 150 100 200 50 ANCESTRAL CYNODONT 0 Marsupials (324 species) Eutherians (placental mammals; 5,010 species) Ancestral mammal
    96. 96. Regional Adaptive Radiations <ul><li>Adaptive radiations can occur when organisms colonize new environments with little competition </li></ul><ul><li>The Hawaiian Islands are one of the world’s great showcases of adaptive radiation </li></ul>
    97. 97. Fig. 25-18 Close North American relative, the tarweed Carlquistia muirii Argyroxiphium sandwicense Dubautia linearis Dubautia scabra Dubautia waialealae Dubautia laxa HAWAII 0.4 million years OAHU 3.7 million years KAUAI 5.1 million years 1.3 million years MOLOKAI MAUI LANAI
    98. 98. Fig. 25-18a HAWAII 0.4 million years OAHU 3.7 million years KAUAI 5.1 million years 1.3 million years MOLOKAI MAUI LANAI
    99. 99. Fig. 25-18b Close North American relative, the tarweed Carlquistia muirii
    100. 100. Fig. 25-18c Dubautia waialealae
    101. 101. Fig. 25-18d Dubautia laxa
    102. 102. Fig. 25-18e Dubautia scabra
    103. 103. Fig. 25-18f Argyroxiphium sandwicense
    104. 104. Fig. 25-18g Dubautia linearis
    105. 105. <ul><li>Studying genetic mechanisms of change can provide insight into large-scale evolutionary change </li></ul>Concept 25.5: Major changes in body form can result from changes in the sequences and regulation of developmental genes
    106. 106. Evolutionary Effects of Development Genes <ul><li>Genes that program development control the rate, timing, and spatial pattern of changes in an organism’s form as it develops into an adult </li></ul>
    107. 107. Changes in Rate and Timing <ul><li>Heterochrony is an evolutionary change in the rate or timing of developmental events </li></ul><ul><li>It can have a significant impact on body shape </li></ul><ul><li>The contrasting shapes of human and chimpanzee skulls are the result of small changes in relative growth rates </li></ul>Animation: Allometric Growth
    108. 108. Fig. 25-19 (a) Differential growth rates in a human (b) Comparison of chimpanzee and human skull growth Newborn Age (years) Adult 15 5 2 Chimpanzee fetus Chimpanzee adult Human fetus Human adult
    109. 109. Fig. 25-19a (a) Differential growth rates in a human Newborn Age (years) Adult 15 5 2
    110. 110. Fig. 25-19b (b) Comparison of chimpanzee and human skull growth Chimpanzee fetus Chimpanzee adult Human fetus Human adult
    111. 111. <ul><li>Heterochrony can alter the timing of reproductive development relative to the development of nonreproductive organs </li></ul><ul><li>In paedomorphosis , the rate of reproductive development accelerates compared with somatic development </li></ul><ul><li>The sexually mature species may retain body features that were juvenile structures in an ancestral species </li></ul>
    112. 112. Fig. 25-20 Gills
    113. 113. Changes in Spatial Pattern <ul><li>Substantial evolutionary change can also result from alterations in genes that control the placement and organization of body parts </li></ul><ul><li>Homeotic genes determine such basic features as where wings and legs will develop on a bird or how a flower’s parts are arranged </li></ul>
    114. 114. <ul><li>Hox genes are a class of homeotic genes that provide positional information during development </li></ul><ul><li>If Hox genes are expressed in the wrong location, body parts can be produced in the wrong location </li></ul><ul><li>For example, in crustaceans, a swimming appendage can be produced instead of a feeding appendage </li></ul>
    115. 115. <ul><li>Evolution of vertebrates from invertebrate animals was associated with alterations in Hox genes </li></ul><ul><li>Two duplications of Hox genes have occurred in the vertebrate lineage </li></ul><ul><li>These duplications may have been important in the evolution of new vertebrate characteristics </li></ul>
    116. 116. Fig. 25-21 Vertebrates (with jaws) with four Hox clusters Hypothetical early vertebrates (jawless) with two Hox clusters Hypothetical vertebrate ancestor (invertebrate) with a single Hox cluster Second Hox duplication First Hox duplication
    117. 117. The Evolution of Development <ul><li>The tremendous increase in diversity during the Cambrian explosion is a puzzle </li></ul><ul><li>Developmental genes may play an especially important role </li></ul><ul><li>Changes in developmental genes can result in new morphological forms </li></ul>
    118. 118. Changes in Genes <ul><li>New morphological forms likely come from gene duplication events that produce new developmental genes </li></ul><ul><li>A possible mechanism for the evolution of six-legged insects from a many-legged crustacean ancestor has been demonstrated in lab experiments </li></ul><ul><li>Specific changes in the Ubx gene have been identified that can “turn off” leg development </li></ul>
    119. 119. Fig. 25-22 Hox gene 6 Hox gene 7 Hox gene 8 About 400 mya Drosophila Artemia Ubx
    120. 120. Changes in Gene Regulation <ul><li>Changes in the form of organisms may be caused more often by changes in the regulation of developmental genes instead of changes in their sequence </li></ul><ul><li>For example three-spine sticklebacks in lakes have fewer spines than their marine relatives </li></ul><ul><li>The gene sequence remains the same, but the regulation of gene expression is different in the two groups of fish </li></ul>
    121. 121. Fig. 25-23 Test of Hypothesis A: Differences in the coding sequence of the Pitx1 gene? Result: No Marine stickleback embryo Close-up of ventral surface Test of Hypothesis B: Differences in the regulation of expression of Pitx1 ? Pitx1 is expressed in the ventral spine and mouth regions of developing marine sticklebacks but only in the mouth region of developing lake stickbacks. The 283 amino acids of the Pitx1 protein are identical. Result: Yes Lake stickleback embryo Close-up of mouth RESULTS
    122. 122. Fig. 25-23a Marine stickleback embryo Close-up of ventral surface Lake stickleback embryo Close-up of mouth
    123. 123. Concept 25.6: Evolution is not goal oriented <ul><li>Evolution is like tinkering—it is a process in which new forms arise by the slight modification of existing forms </li></ul>
    124. 124. Evolutionary Novelties <ul><li>Most novel biological structures evolve in many stages from previously existing structures </li></ul><ul><li>Complex eyes have evolved from simple photosensitive cells independently many times </li></ul><ul><li>Exaptations are structures that evolve in one context but become co-opted for a different function </li></ul><ul><li>Natural selection can only improve a structure in the context of its current utility </li></ul>
    125. 125. Fig. 25-24 (a) Patch of pigmented cells Optic nerve Pigmented layer (retina) Pigmented cells (photoreceptors) Fluid-filled cavity Epithelium Epithelium (c) Pinhole camera-type eye Optic nerve Cornea Retina Lens (e) Complex camera-type eye (d) Eye with primitive lens Optic nerve Cornea Cellular mass (lens) (b) Eyecup Pigmented cells Nerve fibers Nerve fibers
    126. 126. Evolutionary Trends <ul><li>Extracting a single evolutionary progression from the fossil record can be misleading </li></ul><ul><li>Apparent trends should be examined in a broader context </li></ul>
    127. 127. Fig. 25-25 Recent (11,500 ya) Neohipparion Pliocene (5.3 mya) Pleistocene (1.8 mya) Hipparion Nannippus Equus Pliohippus Hippidion and other genera Callippus Merychippus Archaeohippus Megahippus Hypohippus Parahippus Anchitherium Sinohippus Miocene (23 mya) Oligocene (33.9 mya) Eocene (55.8 mya) Miohippus Paleotherium Propalaeotherium Pachynolophus Hyracotherium Orohippus Mesohippus Epihippus Browsers Grazers Key
    128. 128. Fig. 25-25a Oligocene (33.9 mya) Eocene (55.8 mya) Miohippus Paleotherium Propalaeotherium Pachynolophus Hyracotherium Orohippus Mesohippus Epihippus Browsers Grazers Key
    129. 129. Fig. 25-25b Recent (11,500 ya) Neohipparion Pliocene (5.3 mya) Pleistocene (1.8 mya) Hipparion Nannippus Equus Pliohippus Hippidion and other genera Callippus Merychippus Archaeohippus Megahippus Hypohippus Parahippus Anchitherium Sinohippus Miocene (23 mya)
    130. 130. <ul><li>According to the species selection model, trends may result when species with certain characteristics endure longer and speciate more often than those with other characteristics </li></ul><ul><li>The appearance of an evolutionary trend does not imply that there is some intrinsic drive toward a particular phenotype </li></ul>
    131. 131. Fig 25-UN8 Millions of years ago (mya) 1.2 bya: First multicellular eukaryotes 2.1 bya: First eukaryotes (single-celled) 3.5 billion years ago (bya): First prokaryotes (single-celled) 535–525 mya: Cambrian explosion (great increase in diversity of animal forms) 500 mya: Colonization of land by fungi, plants and animals Present 500 2,000 1,500 1,000 3,000 2,500 3,500 4,000
    132. 132. Fig 25-UN9 Origin of solar system and Earth 4 3 2 1 Paleozoic Meso- zoic Ceno- zoic Proterozoic Archaean Billions of years ago
    133. 133. Fig 25-UN10 Flies and fleas Moths and butterflies Caddisflies Herbivory
    134. 134. Fig 25-UN11 Origin of solar system and Earth 4 3 2 1 Paleozoic Meso- zoic Ceno- zoic Proterozoic Archaean Billions of years ago
    135. 135. You should now be able to: <ul><li>Define radiometric dating, serial endosymbiosis, Pangaea, snowball Earth, exaptation, heterochrony, and paedomorphosis </li></ul><ul><li>Describe the contributions made by Oparin, Haldane, Miller, and Urey toward understanding the origin of organic molecules </li></ul><ul><li>Explain why RNA, not DNA, was likely the first genetic material </li></ul>
    136. 136. <ul><li>Describe and suggest evidence for the major events in the history of life on Earth from Earth’s origin to 2 billion years ago </li></ul><ul><li>Briefly describe the Cambrian explosion </li></ul><ul><li>Explain how continental drift led to Australia’s unique flora and fauna </li></ul><ul><li>Describe the mass extinctions that ended the Permian and Cretaceous periods </li></ul><ul><li>Explain the function of Hox genes </li></ul>

    ×