Evolution lectures 3&4 September 2013

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Queen Mary U London
SBC174/SBS110 Evolution lectures from September 30th.

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Evolution lectures 3&4 September 2013

  1. 1. Mini-summary of lectures 1 & 2 Monday, 30 September 13
  2. 2. Specific Questions/Comments Geologists (Hutton, Lyell): Uniformitarianism: Changes in nature are gradual. In 1800s, fossils showed species that no longer existed: Some (e.g. Cuvier): Catastrophism: Fossils show extinct species (due to major, sudden, catastrophic events). Monday, 30 September 13
  3. 3. 3 Schools of evolutionary thought • Lamarck: characteristics acquired by an individual are passed on to offspring. • Linneaus: each species was separately created. • Darwin & Wallace: evolution as descent with modification. Monday, 30 September 13
  4. 4. Evolution by Natural Selection • There is inherited variation within species. • There is competition for survival within species. • Genetically inherited traits affect reproduction or survival.Thus the frequencies of variants change. (Not just numbers of offspring!) Evolutionary fitness: A measure of the ability of genetic material to perpetuate itself in the course of evolution. Depends on the individual’s ability to survive, the rate of reproduction and the viability of offspring. Monday, 30 September 13
  5. 5. “Neo-Darwinism” or “The Modern Synthesis” The same thing... but with better understanding of how things work. • Darwin’sTheory of Evolution by Natural Selection (1859) • Mendel’s Laws of Heredity (1866, 1900; see SBS 008) • Cytogenetics (1902, 1904 - ) • Population Genetics (1908; see Lectures 7-12) • Molecular genetics (1970s- ; see SBS 633/210 and Lecture 6) •More stuff since then (cultural evolution, epigenetics, etc...) Monday, 30 September 13
  6. 6. •Evolution also occurs by: •genetic drift •sexual selection •... Natural selection leads to adaptive change •But environmental conditions change: What was advantageous yesterday may be a disadvantage today. But not all change is adaptive! Monday, 30 September 13
  7. 7. Paperback 596 pages (11 Aug 2005) Publisher: Oxford University Press Monday, 30 September 13
  8. 8. Monday, 30 September 13
  9. 9. 1. The Fossil Record 2. Comparative Anatomy 3. Comparative Embryology 4. Vestigial Structures 5. Domestication (artificial selection) Darwin’s evidence for evolution Monday, 30 September 13
  10. 10. Geological times & continental drift Monday, 30 September 13
  11. 11. Today 1. Major transitions in evolution 2. Geological timescales 3. Major geological drivers of evolution 4. Recent major extinction events Monday, 30 September 13
  12. 12. Major transitions? 1.Smaller entities coming together to form larger entities. (e.g. eukaryotes, multicellularity, colonies...) 2.Smaller entities become differentiated as part of larger entity. (e.g. organelles, anisogamy, tissues, castes...) 3.Smaller entities are often unable to replicate without the larger entity. (e.g. organelles, tissues, castes...). 4.The smaller entities can disrupt the development of the larger entity, (e.g. Meiotic drive, parthenogenesis, cancer...) 5.New ways of transmitting information arise (e.g. DNA-protein, indirect fitness...) Maynard Smith and Szathmary 1995 Monday, 30 September 13
  13. 13. Major transitions: early life 1953 Miller-Urey “primitive soup” experiment 350° vs 0° ➔ organic molecules Monday, 30 September 13
  14. 14. Major transitions: early life •Organic molecules ≠ Life •Early life: •Hereditary replication •Compartmentalization •First hereditary information? Monday, 30 September 13
  15. 15. Phylogenetic Tree of Life Bacteria Green Filamentous bacteriaSpirochetes Gram positives Proteobacteria Cyanobacteria Planctomyces Bacteroides Cytophaga Thermotoga Aquifex Halophiles Methanosarcina Methanobacterium Methanococcus T. celer Thermoproteus Pyrodicticum Entamoebae Slime molds Animals Fungi Plants Ciliates Flagellates Trichomonads Microsporidia Diplomonads Archaea Eukaryota last universal common ancestor (LUCA) Woese 1990 tree based on ribosomalRNA sequences Monday, 30 September 13
  16. 16. Major transitions: early life •Organic molecules ≠ Life •Early life of simple replicators: •Hereditary replication •Compartmentalization •First hereditary information? •Probably RNA: Genetic information (that can be copied) + Enzymatic activity. •Amino-acids (initially as co-factors) •DNA (much more stable than RNA) •Linkage of replicators (chromosomes) Monday, 30 September 13
  17. 17. Major transitions: Prokaryote to Eukaryote Prokaryotic cell Cell membrane infoldings Cell membrane Cytoplasm Nucleoid (containingDNA) Endomembrane system Endoplasmic reticulum Nuclear membrane Nucleus Proteobacterium Mitochondria Cyanobacterium Chloroplasts Mitochondrion † † † 1 Aprokaryote grows in size and develops infoldings in its cell membrane to increase its surface area to volume ratio. 2 The infoldings eventually pinch off from the cell membrane, forming an early endomembrane system. It encloses the nucleoid, making a membrane-bound nucleus. This is the first eukaryote. 3 5 Some eukaryotes go on to acquire add endosymbionts—the cyanobacteria, a g of bacteria capable of photosynthesis. They become chloroplasts. Ancestor of plants and algæ Ancestor of animals, fungi, and other heterotrophs First eukaryote The aerobe's ability to use oxygen to make energy be- comes an asset for the host, allowing it to thrive in an in- creasingly oxygen-rich environ- ment as the other eukaryotes go extinct. The proteobacterium is eventually assimilated and becomes a mitochondrion. Some eukaryotes go on to ac- quire additional endosymbionts — the cyanobacteria, a group of bacteria capable of photosynthe- sis. They become chloroplasts.Anaerobic (oxygen using) proteo- bacterium enters the eukaryote, either as prey or a parasite, and manages to avoid digestion. It becomes an endosymbiont, or a cell living inside another cell. Monday, 30 September 13
  18. 18. Major transitions: sex •See lectures Week 5. Monday, 30 September 13
  19. 19. Major transitions: multicellularity Monday, 30 September 13
  20. 20. Major transitions: multicellularity Green algae: Inspiration for what may have occurred: Volvocales Monday, 30 September 13
  21. 21. Major transitions: multicellularity Green algae: Inspiration for what may have occurred: Volvocales Monday, 30 September 13
  22. 22. e.g.: artificial selection for multicellularity in S. cerevisiae yeast Ratcliff et al 2012 Monday, 30 September 13
  23. 23. Major transitions: multicellularity Green algae: Inspiration for what may have occurred: Volvocales Monday, 30 September 13
  24. 24. Volvox Somatic cells Gonidia Monday, 30 September 13
  25. 25. Major transitions: eusociality •Solitary lifestyle --> Eusociality 1. Reproductive division of labor 2. Overlapping generations (older offspring help younger offspring) 3. Cooperative care of young Eg: ants, bees, wasps, termites. But also: naked mole rats, a beetle, a shrimp... Monday, 30 September 13
  26. 26. Hamilton, 1964 Major transitions: eusociality •Kin selection: can favor the reproductive success of an organism's relatives (ie. indirect fitness), even at a cost to the organism's own survival and reproduction. •Hamilton’s rule: genes for altruism increase in frequency when: indirect fitness benefits to the receiver (B) , B exceeds costs to the altruist (C). > Cr × reduced by the coefficient of relatedness (r), Monday, 30 September 13
  27. 27. © Alex Wild & others Monday, 30 September 13
  28. 28. © National Geographic Atta leaf-cutter ants Monday, 30 September 13
  29. 29. © National Geographic Atta leaf-cutter ants Monday, 30 September 13
  30. 30. © National Geographic Atta leaf-cutter ants Monday, 30 September 13
  31. 31. Monday, 30 September 13
  32. 32. Oecophylla Weaver ants © ameisenforum.de Monday, 30 September 13
  33. 33. © ameisenforum.de Fourmis tisserandes Monday, 30 September 13
  34. 34. © ameisenforum.de Oecophylla Weaver ants Monday, 30 September 13
  35. 35. © forestryimages.org© wynnie@flickr Monday, 30 September 13
  36. 36. Tofilski et al 2008 Forelius pusillus Monday, 30 September 13
  37. 37. Tofilski et al 2008 Forelius pusillus hides the nest entrance at night Monday, 30 September 13
  38. 38. Tofilski et al 2008 Forelius pusillus hides the nest entrance at night Monday, 30 September 13
  39. 39. Tofilski et al 2008 Forelius pusillus hides the nest entrance at night Monday, 30 September 13
  40. 40. Tofilski et al 2008 Forelius pusillus hides the nest entrance at night Monday, 30 September 13
  41. 41. Avant Workers staying outside die « preventive self-sacrifice » Tofilski et al 2008 Forelius pusillus hides the nest entrance at night Monday, 30 September 13
  42. 42. Dorylus driver ants: ants with no home © BBC Monday, 30 September 13
  43. 43. Animal biomass (Brazilian rainforest) from Fittkau & Klinge 1973 Other insects Amphibians Reptiles Birds Mammals Earthworms Spiders Soil fauna excluding earthworms, ants & termites Ants & termites Monday, 30 September 13
  44. 44. Today 1. Major transitions in evolution 2. Geological timescales 3. Major geological drivers of evolution 4. Recent major extinction events Monday, 30 September 13
  45. 45. Monday, 30 September 13
  46. 46. elisa.piccaro@qmul.ac.uk Send your student id & tell her to add you to this module. If QMPlus isn’t working Monday, 30 September 13
  47. 47. “Complexity of life” didn’t increase linearly. 2. Geological time scales Defined by changes in flora and fauna (seen in fossil record). Eon > Era > Period > Epoch Monday, 30 September 13
  48. 48. 4550 Ma: Hominids Mammals Land plants Animals Multicellular life Eukaryotes Prokaryotes Hadean Archean Proterozoic Paleozoic Mesozoic Cenozoic 4527 Ma: Formation of the Moon 4.6 Ga 4 Ga 3.8Ga 3 Ga 2.5 Ga 2 Ga 1 Ga 542 M a 251 Ma 65 Ma ca. 4000 Ma: End of the Late Heavy Bombardment; first life ca. 3500 Ma: Photosynthesis starts ca. 2300 Ma: Atmosphere becomes oxygen-rich; 750-635 Ma: wo Snowball Earths ca. 530 Ma: ambrian explosion ca. 380 Ma: First vertebrate land animals 230-65 Ma: Dinosaurs 2 Ma: First Hominids Ga = Billion years ago Ma = Million years ago Eon Eon Eon Era Era Era Phanerozoic Eon Geological timescales: Eon > Era > Period > Epoch Monday, 30 September 13
  49. 49. End of Proterozoic biota Dickinsonia Monday, 30 September 13
  50. 50. Trilobites Cambrian to late permian Monday, 30 September 13
  51. 51. 50100150200250300350400450500 0542 0 1 2 3 4 5 Millions of Years Ago ThousandsofGenera Cm O S D C P T J K Pg N Biodiversity during the Phanerozoic All Genera Well-Resolved Genera Long-Term Trend The “Big 5” Mass Extinctions Other Extinction Events Monday, 30 September 13
  52. 52. 4550 Ma: Hominids Mammals Land plants Animals Multicellular life Eukaryotes Prokaryotes Hadean Archean Proterozoic Paleozoic Mesozoic Cenozoic 4527 Ma: Formation of the Moon 4.6 Ga 4 Ga 3.8Ga 3 Ga 2.5 Ga 2 Ga 1 Ga 542 M a 251 Ma 65 Ma ca. 4000 Ma: End of the Late Heavy Bombardment; first life ca. 3500 Ma: Photosynthesis starts ca. 2300 Ma: Atmosphere becomes oxygen-rich; 750-635 Ma: wo Snowball Earths ca. 530 Ma: ambrian explosion ca. 380 Ma: First vertebrate land animals 230-65 Ma: Dinosaurs 2 Ma: First Hominids Ga = Billion years ago Ma = Million years ago Eon Eon Eon Era Era Era Phanerozoic Eon Geological timescales: Eon > Era > Period > Epoch Monday, 30 September 13
  53. 53. Earth Life Eukaryotes H om o sapiens: 5 m eters W hitechapel: D inosaurs extin N H M :first tetrapod Ham m ersm ith:Cam brian explosion Monday, 30 September 13
  54. 54. Today 1. Major transitions in evolution 2. Geological timescales 3. Major geological drivers of evolution 4. Recent major extinction events Monday, 30 September 13
  55. 55. 3. Major geological drivers of evolution •Tectonic movement (of continental plates) •Vulcanism •Climate change •Meteorites Conditions on earth change. Monday, 30 September 13
  56. 56. Plate tectonics 12 3 54 Monday, 30 September 13
  57. 57. Crustal plates and continental drift Monday, 30 September 13
  58. 58. Recent continental movements... TETHYS SEA LAURASIA GONDWANA EquatorTriassic 200 Mya Pangaea - single supercontinent Monday, 30 September 13
  59. 59. Fossil distribution Gondwana Monday, 30 September 13
  60. 60. Earthquakes •Some tectonic movement is violent. •E.g. 2004 Sumatra earthquake & tsunami... Monday, 30 September 13
  61. 61. Vulcanism •Local climate change (e.g. thermal vents, hot springs...) •Global climate change: Emission of gasses & particles. •New geological barriers (migration...) •New islands (“Malay archipelago”, Galapagos... Hawaii... ) Deccan traps Eyjafjall ajokull Monday, 30 September 13
  62. 62. Climate change (since Cambrian) Monday, 30 September 13
  63. 63. 3. Major geological drivers of evolution •Tectonic movement (of continental plates) •Vulcanism •Climate change •Meteorites Conditions on earth change. Monday, 30 September 13
  64. 64. Vulcanism Tectonic movement Meteorite impact Climate change? ? Consequences: • Large scale migrations • Speciation • Mass extinctions • Adaptive radiations 3. Major geological drivers of evolution Monday, 30 September 13
  65. 65. Today 1. Major transitions in evolution 2. Geological timescales 3. Major geological drivers of evolution 4. Recent major extinction events Monday, 30 September 13
  66. 66. 4. Recent major extinction events Pg fraction of genera present in each time interval but extinct in the following interval KT:K-PgCretaceous–Paleogene T riassic-Jurassic Perm ian-Triassic LateDevonian Ordovician–Silurian Today Monday, 30 September 13
  67. 67. Monday, 30 September 13
  68. 68. •Oxygen levels. •Tetrapods and early amniotes. •Tropical conditions around equatorial landmasses. • Damp forests: tall trees & lush undergrowth: giant club mosses, lycopods, ferns & seed ferns. • Decaying undergrowth forms coal. • Good habitats for terrestrial invertebrates including spiders, millipedes and insects (e.g. giant dragonflies). Pangaea - single supercontinent Carboniferous/Permian Monday, 30 September 13
  69. 69. Dimetrodon (sub-class Synapsida = “mammal-like reptiles”) Early Permian mammal-like reptiles Monday, 30 September 13
  70. 70. Climate change (since Cambrian) Monday, 30 September 13
  71. 71. Permian-Triassic Extinction Sun et al Science 2012 Went extinct: •Up to 96% of marine species & 70% of terrestrial vertebrates •21 terrestrial tetrapod families (63%) • 7 orders of insects Monday, 30 September 13
  72. 72. Monday, 30 September 13
  73. 73. Jurassic/Cretaceous •Mammal-like reptiles were replaced as dominant land vertebrates by reptiles (dinosaurs). • Lizards, modern amphibians and early birds appear. • The conifer- and fern-dominated vegetation of the LateTriassic continued into the Jurassic. Monday, 30 September 13
  74. 74. Cretaceous–Paleogene (KT) extinction 66 million years ago Subsequently, many adaptive radiations to fill newly vacant niches. eg. mammals, fish, many insects Ammonite Mosasaur (marine reptile) Non-bird dinosaurs Most Plant-eating insects 75% of all species became extinct (50% of genera). Including: Monday, 30 September 13
  75. 75. http://www.scotese.com/earth.htm) Cretaceous–Paleogene (KT) extinction 66 million years ago Monday, 30 September 13
  76. 76. Evidence for Chixulub impact Magnetic field near site Crater: 180km diameter; bolide: 10km. Monday, 30 September 13
  77. 77. •Bolide impact at Chixulub. •huge tsunamis •cloud of dust and water vapour, blocking sun. •plants & phytoplankton die (bottom of food chain) --> animals starve •dramatic climate & temperature changes are difficult (easier for warm-blooded?) •Additional causes? •Some groups were ALREADY in decline •Additional impacts? •Deccan traps (India) - 30,000 years of volcanic activity (lava/gas release) Cretaceous–Paleogene (KT) extinction 66 million years ago Monday, 30 September 13
  78. 78. Monday, 30 September 13
  79. 79. Diprotodon, Australia, extinct 40,000 ya Dodo, Mauritius, extinct since 1662 Ongoing Anthropocene extinction •Hunting •Habitat destruction, modification & fragmentation Passenger Pigeon North America; extinct since 1914. Glyptodon, Americas, extinct ~12000 years ago Monday, 30 September 13
  80. 80. Ongoing Anthropocene extinction •Hunting •Habitat destruction, modification & fragmentation •Pollution/Overexploitation •Spread of invasive species - & new pathogens •Climate change Monday, 30 September 13
  81. 81. Rainforest loss in Sumatra Margono et al 2012 Monday, 30 September 13
  82. 82. Summary. •The history of the earth is divided into geological time periods • These are defined by characteristic flora and fauna •Large-scale changes in biodiversity (mass extinctions) were triggered by continental movement and catastrophic events Monday, 30 September 13
  83. 83. QMPlus Fail. http://www.slideshare.net/yannickwurm/ http://qmplus.qmul.ac.uk/course/view.php?id=3972 Week 3: Fossils, DNA and Molecules twitter: yannick__ Monday, 30 September 13

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