Evolution

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Evolution

  1. 1. EVOLUTION
  2. 2. http://www.youtube.com/watch?v=lhTSfOZUNLo
  3. 3. http://www.youtube.com/watch?v=HU4xmWwYA2A
  4. 4. Early Theories on Land <ul><li>Oparin’s Primordial Soup – energy from sun, lightning, and heat; chemical reaction formed life in water, life emerged </li></ul><ul><li>The Big Bang Theory – lightning and gases </li></ul><ul><li>Intelligent Design </li></ul><ul><li>The Alien Theory </li></ul>
  5. 6. Early Theories on Life <ul><li>Spontaneous Generation </li></ul><ul><ul><li>Disproved by F. Redi </li></ul></ul><ul><ul><li>Meat and Maggots Experiment </li></ul></ul><ul><ul><li>People still believed microorganisms spontaneously generated </li></ul></ul><ul><ul><li>Pasteur’s experiment provided final proof of biogenesis </li></ul></ul>
  6. 8. What data do we have? <ul><ul><li>Fossils: </li></ul></ul><ul><ul><li>Trace – indirect, footprints </li></ul></ul><ul><ul><li>Casts – rocks filled in </li></ul></ul><ul><ul><li>space of decayed </li></ul></ul><ul><ul><li>animal </li></ul></ul><ul><ul><li>Molds – organism </li></ul></ul><ul><ul><li>decays into sediment </li></ul></ul><ul><ul><li>Petrified – minerals replace organism </li></ul></ul><ul><ul><li>Amber/Frozen – trapped in ice </li></ul></ul>
  7. 9. <ul><li>Determine environment </li></ul><ul><li>Determine species </li></ul><ul><ul><li>Habitat </li></ul></ul><ul><ul><li>Diet </li></ul></ul><ul><ul><li>Size </li></ul></ul><ul><ul><li>Shape </li></ul></ul>Use of Fossils by Paleontologists
  8. 11. Endosymbiotic Theory <ul><li>Aerobic bacteria are highly efficient at producing ATP </li></ul><ul><li>Early organisms engulfed aerobic bacteria </li></ul><ul><li>Bacteria “evolved” into mitochondria </li></ul><ul><li>Proof: mitochondria contain their own DNA and ribosomes </li></ul>
  9. 12. Aerobic bacteria Ancient Prokaryotes Ancient Anaerobic Prokaryote Primitive Aerobic Eukaryote Primitive Photosynthetic Eukaryote Chloroplast Photosynthetic bacteria Nuclear envelope evolving Mitochondrion Plants and plantlike protists Animals, fungi, and non-plantlike protists The endosymbiotic theory proposes that eukaryotic cells arose from living communities formed by prokaryotes organisms. Ancient prokaryotes may have entered primitive eukaryotic cells and remained there as organelles.
  10. 13. Fossil Data for Evolution <ul><li>Homologous structures </li></ul><ul><ul><li>Similar structure and function between species </li></ul></ul><ul><ul><li>Gorilla arms and human arms </li></ul></ul><ul><li>Analogous structures </li></ul><ul><ul><li>Similar function but different structures </li></ul></ul><ul><ul><li>Bird wings and butterfly wings </li></ul></ul><ul><li>Vestigial structures </li></ul><ul><ul><li>Structures that are no longer needed and are slowly fading out of society </li></ul></ul><ul><ul><li>Wisdom teeth, appendix </li></ul></ul>
  11. 14. Homologous Structures Analogous Structures
  12. 15. Cassowary Whale pelvis and thigh bone Mexican Blind Cave Fish <ul><li>Human Vestigial Structures: </li></ul><ul><li>erector pili are smooth muscle fibers that give humans “goose bumps </li></ul><ul><li>Tailbone </li></ul><ul><li>Wisdom teeth </li></ul><ul><li>appendix </li></ul>
  13. 17. Evolutionary Data A body plan shared by vertebrates shows embryological development, suggesting common descent
  14. 18. Charles Darwin <ul><li>Father was a doctor </li></ul><ul><li>Worked towards a </li></ul><ul><li>degree in Theology </li></ul><ul><li>1831 HMS Beagle was </li></ul><ul><ul><li>leaving to return slaves </li></ul></ul><ul><ul><li>to South America </li></ul></ul><ul><li>Darwin was hired as a </li></ul><ul><ul><li>naturalist to record </li></ul></ul><ul><ul><li>information about nature on the voyage </li></ul></ul>
  15. 20. Darwin <ul><li>Galapagos Islands – coast of Ecuador </li></ul><ul><li>Studied bird beaks and turtle size </li></ul><ul><li>Returned to Europe </li></ul><ul><li>Began writing On The Origin of Species , a book about his research </li></ul><ul><li>Darwin did not publish until another scientist was about to publish similar work, Wallace (28 years later) </li></ul>
  16. 21. Charles Darwin, last sentence of On the Origin of Species “ There is a grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one: and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.”
  17. 22. Adaptive Radiation
  18. 23. How does adaptive radiation work?
  19. 24. Natural Selection <ul><li>Genetic variation among species </li></ul><ul><li>Environmental challenges </li></ul><ul><li>Struggle to survive </li></ul><ul><li>Survival of the fittest </li></ul><ul><li>Traits best suited will increase in the population </li></ul>
  20. 25. Examples of Natural Selection <ul><li>Bacterial resistance to antibiotics </li></ul><ul><li>Insect resistance to pesticides </li></ul><ul><li>Industrial melanism </li></ul>
  21. 27. Mimicry
  22. 28. Types of Natural Selection <ul><li>Stabilizing </li></ul><ul><ul><li>Favors average individual </li></ul></ul><ul><ul><li>Big spiders are easily spotted, little ones can’t get food </li></ul></ul><ul><li>Directional </li></ul><ul><ul><li>Favors one extreme population </li></ul></ul><ul><ul><li>Long bird beaks get more food when supply is low </li></ul></ul><ul><li>Disruptive </li></ul><ul><ul><li>Both extremes selected for </li></ul></ul><ul><ul><li>Dark, medium, and light colored fish – medium fish is seen in both environments </li></ul></ul>
  23. 29. Directional Selection Directional Selection Food becomes scarce. Key Low mortality, high fitness High mortality, low fitness
  24. 30. Stabilizing Selection Key Percentage of Population Birth Weight Selection against both extremes keep curve narrow and in same place. Low mortality, high fitness High mortality, low fitness Stabilizing Selection
  25. 31. Disruptive Selection Disruptive Selection Largest and smallest seeds become more common. Number of Birds in Population Beak Size Population splits into two subgroups specializing in different seeds. Beak Size Number of Birds in Population Key Low mortality, high fitness High mortality, low fitness
  26. 32. Artificial Selection
  27. 33. Speciation <ul><li>Evolution of a new species </li></ul><ul><li>Geographic isolation </li></ul><ul><li>Tree frogs in rainforest </li></ul><ul><ul><li>Single population </li></ul></ul><ul><ul><li>Divided by river </li></ul></ul><ul><ul><li>Over time, two species created and cannot interbreed </li></ul></ul>
  28. 34. Behavioral Isolation <ul><li>These meadowlarks have overlapping ranges, but do not interbreed because they have different mating songs. </li></ul><ul><li>Can you tell which one is the Eastern and which one is the Western Meadowlark? </li></ul>
  29. 35. Geographic Isolation

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