Evolution Natural Selection And Speciation 6371
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  • 1. Evidence of Change Evolution
  • 2. “Evolve” Means to Change Over Time
    • The belief that life on Earth has changed over time is quite old
    • To be considered science, this belief requires a great deal of evidence
    Evolution
  • 3. The Development of Evolutionary Theory
    • Naturalists have always wondered at the diversity of living things………
    • Great varieties in shape, size, and ecological role
    • Estimated 3 million to 20 million different living species
    • Much of the natural world’s biodiversity has vanished through extinction
    • 99% of all species that ever lived are now extinct
    • Permian-Triassic Mass Extinction
    • What Killed the Dinosaurs?
    Evolution
  • 4. Development of Evolutionary Theory
    • What could cause such great diversity, and why have so many species died out?
    • Charles Darwin offered an explanation based on careful observations
    • Who was Charles Darwin?
    Evolution
  • 5. Development of Evolutionary Theory
    • Darwin Concluded:
    • Physical traits and behaviors enable organisms to survive and reproduce (called Fitness )
    • Fitness results from adaptations
    • Darwin reasoned that adaptations result from natural selection and result in evolution
    Evolution Evolution is the process by which living things change and diversify over time
  • 6. Development of Evolutionary Theory
    • These ideas were widely challenged until a tremendous amount of evidence was gathered to support evolution!
    • Now…The Theory of Evolution is the Cornerstone of Biology
    • Explore the Evolution Revolution
    Evolution
  • 7. Evolution Evidence to Support Evolution
  • 8.
    • The Origin of Life
    • Geology
    • The Fossil Record
    • Comparative Embryology
    • Comparative Biochemistry
    • Comparative Anatomy
    • Isn’t Evolution Just a Theory?
    Scientists from many disciplines including biology, chemistry, physics, geology, and paleontology have contributed to the case for evolution! Evidence to Support Evolution
  • 9. The Origin of Life
    • Origin of the Universe
    • Big Bang ( animation )
    • Early Earth
    • Evolution Starts Up: Chemical Evolution
    • Heterotroph Hypothesis: Molecules of life arose from inorganic building blocks
    Evidence to Support Evolution
  • 10. The Miller-Urey Experiment
    • Studied Molecules Present at Time of Early Earth
    • Methane, Ammonia, Carbon Dioxide, Water Vapor
    • Mixed Molecules in Reaction Chamber
    • Sparked with Electricity to Simulate Lightning
    • Exposed Mixture to UV Radiation to Simulate Cosmic Rays
    • Produced Basic Amino Acids and Organic Molecules
    Evidence to Support Evolution
  • 11. Miller-Urey Apparatus Evidence to Support Evolution
  • 12. Biological Evolution
    • RNA as a information molecule and catalyst
    • Endosymbiotic Theory
      • Mitochondria and chloroplasts were originally free living prokaryotic cells
      • Both have own DNA and ribosomes
      • Joined together to cooperate
  • 13. Geology
    • The Study of the Earth and Rocks
    • Early Ideas About Earth:
      • People believed Earth was only a few thousand years old
      • People believed that rocks and geological features were shaped by catastrophic events and rarely changed
    Evidence to Support Evolution
  • 14. Geology
    • In the 18 th and 19 th Century Scientists Studied Geology in Great Detail
      • Over millions of years 1 original continent Pangea drifted apart to make our modern continents
      • Continental drift is gradual “gradualism”
    Evidence to Support Evolution
  • 15. Geology
    • Hutton and Lyell: Earth is Changed by Weather and Natural Processes like Volcanoes and Erosion
    • Takes a Very Long Time!
  • 16. Geology
    • These ideas refute the idea that the Earth is only a few thousand years old
    • Backed up by radiometric dating
      • The Earth is approximately 4.6 Billion Years Old
      • 4,600,000,000 years is a long time!
    Evidence to Support Evolution
  • 17. The Fossil Record
    • Fossils are the preserved remains of ancient organisms
      • Provide information about past organisms
      • Shows that many diverse organisms lived at different times in Earth’s History
    Evidence to Support Evolution                                     
  • 18. The Fossil Record
    • Taphonomy: The Formation of Fossils
      • Fossils form in sedimentary rock
      • Dead organisms covered by sand and silt
      • Sediments are passed into bone by pressure from above (fossils form in sedimentary rock)
      • Video
    Evidence to Support Evolution
  • 19. Determining the Age of Fossils
    • Relative Dating: Technique used by scientists to determine the age of fossils relative to fossils in other layers of rock
      • Different layers represent different geologic periods
      • Older fossils found in lower layers, newer fossils found in upper layers
      • Cannot determine the actual age of the fossil!
    Evidence to Support Evolution
  • 20. Determining the Age of Fossils
    • Radioactive Dating: Process by which traces of radioactive elements are analyzed to calculate the actual age of a fossil
    • Many radioactive elements can be used as geologic clocks. Each radioactive element decays at its own nearly constant rate. Once this rate is known, geologists can estimate the length of time over which decay has been occurring by measuring the amount of radioactive parent element and the amount of stable daughter elements
    • Video
    Evidence to Support Evolution
  • 21. Radiometric Dating Evidence to Support Evolution Radioactive Parent Stable Daughter Half life Potassium 40 Argon 40 1.25 billion yrs Rubidium 87 Strontium 87 48.8 billion yrs Thorium 232 Lead 208 14 billion years Uranium 235 Lead 207 704 million years Uranium 238 Lead 206 4.47 billion years Carbon 14 Nitrogen 14 5730 years
  • 22. The Geologic Time Scale
    • Based on fossil and geologic evidence
    • A record of the Earth’s past
    • Divided into Era, Period, and Epoch
    • Shows that life on Earth followed geologic change on Earth
      • Deep Time Activity
      • Interactive Time Scale
    Evidence to Support Evolution
  • 23. Comparative Embryology
    • Embryos are organisms at early stages of development
    Evidence to Support Evolution
  • 24. Comparative Embryology
    • All vertebrate embryos, including humans, share features
      • Eye spot
        • (Evolution of the Human Eye)
      • Gill pouches
      • Notochord
    • Shows similar genetic ancestry
    • Video
    Evidence to Support Evolution
  • 25. Comparative Biochemistry
    • All life is based on organic chemistry
      • Carbon based compounds
    • All life uses same molecule as blueprint
      • DNA
    • Similar chemical processes
      • Bacteria, algae, and plants all do photosynthesis
    • Similar organisms have similar genetic code
      • Humans and chimpanzees share nearly identical genes (98.4% identical gene sequences) Video
    Evidence to Support Evolution
  • 26. Anatomy and Comparative Anatomy
    • Vestigial Organs
      • Organs inherited but not used by modern organisms
      • Present but greatly reduced in modern organisms
      • Hip bone in python
      • Appendix in human
      • Tail bone (cocyx) in human
    Evidence to Support Evolution
  • 27. Anatomy: Homologous Structures
    • Similar parts of different organisms, often quite dissimilar in purpose, that developed from the same ancestral body parts (Video)
    • Divergent evolution
    Evidence to Support Evolution
  • 28. Anatomy: Analogous Structures
    • Similar in purpose, but not inherited from a recent common ancestor
    • Environment selected for trait
      • Wings of birds and insects
    • Convergent evolution
    Evidence to Support Evolution
  • 29. Summary
    • There is overwhelming evidence to support the Theory of Evolution
    • Evidence comes from disciplines as varied as biology, geology, chemistry, physics, astronomy, and paleontology
    • Evolution has produced the great beauty and diversity of life on Earth over the last 4 billion years
    Evidence to Support Evolution
  • 30. Natural Selection and Speciation
  • 31. Charles Darwin
    • Studied Medicine and Theology
    • Excelled in Geology and Biology
    • In 1831 Darwin joined the H.M.S. Beagle on a trip around the world to make maps
    • He was the ship’s naturalist
    • Darwin’s Diary
  • 32. The Voyage of the Beagle: Ports of Call Noted that populations of organisms were slightly different from place to place Each group was modified to their specific environment
  • 33. The Galapagos Archipelago
  • 34. Land Iguana Marine Iguana The Galapagos Iguanas
  • 35. The Galapagos Tortoises
  • 36. The Galapagos Tortoises
  • 37. The Galapagos Finches
  • 38. The Galapagos Finches The Origin of Species Interactive Exploration
  • 39. Evolution Through Natural Selection
    • There is variation in populations caused by genetics (Praying Mantis Camouflage)
    • Many more offspring are produced than can survive. Many die through predation or starvation
    • Some variations are favorable and help organisms compete to survive and reproduce
    • Over time, the organisms with favorable variations become plentiful. The ones without favorable variations become rare or extinct
    • Reluctantly published On the Origin of Species in 1859
    • Video
  • 40. Speciation
    • Natural Selection modifies populations. Some evolutionary changes are so great that some organisms can no longer interbreed with the original population
    • A new species results
    • Species
      • An interbreeding population of organisms that can produce healthy, fertile offspring
  • 41. Reproductive Barriers and Speciation
    • Prezygotic: gametes never meet and fuse
      • Geographic isolation (allopatric speciation)
      • Ecological isolation
      • Behavioral isolation (lacewing songs)
      • Mechanical isolation
      • Seasonal isolation
    • Postzygotic: genetic differences manifest
      • Hybrid inviability
      • Hybrid sterility ( tigons and ligers)
  • 42. Patterns in Evolution
    • Adaptive Radiation
      • Development of numerous new species from a common ancestor in diverse environments
      • Darwin’s Finches (Origin of Species Activity)
    • Gradualism
    • Punctuated Equilibrium
  • 43. Evolution Produces Diversity
    • All living things are classified by characteristics into 5 kingdoms of life
      • Monera: bacteria, unicellular prokaryotes
      • Protista: single celled eukaryotes
      • Fungi: multicellular, eukaryotic, nonmotile, heterotrophs
      • Plantae: multicellular, eukaryotic, autotrophs
      • Animalia: multicellular, eukaryotic, motile, heterotropohs
  • 44. Linnean Taxonomy
    • Example: human classification
      • Kingdom animalia
      • Phylum chordata
      • Class mammalia
      • Order primate
      • Family hominid
      • Genus homo
      • Species sapiens
    • Binomial nomenclature uses genus and species to make the scientific name
    • Homo sapiens
    • Classification activity
  • 45. Human Evolution                          
  • 46. Explore Human Evolution
    • View the Becoming Human broadband documentary
      • As you view each segment, visit the related exhibits to further explore this topic
    • Go to the Learning Center and select the “Calculating Cousins” activity
    • Go to the Learning Center and select the “Chromosome Connection” activity
    • Go to the Learning Center and select the “Building Bodies” activity
  • 47. The Order Primate
    • Characteristics of Primates
      • Strong hands and opposable thumbs
      • Free-moving shoulder joint
      • Forward facing eyes and stereoscopic vision
      • Intelligence/larger brain
      • Social complexity
  • 48. What Characteristics do Humans Have?
    • All of those of primates, plus
      • Upright posture and bipedal
      • Use of tools and technology
      • Advanced intelligence
      • Complex communication and speech
  • 49. The Steps to Human Evolution
    • Terrestrialization
    • Bipedal (Walking on all two’s)
    • Increased Brain Size
    • Civilization
    • Take a look at the Human family tree
  • 50. The Hominid Family
    • Each year new fossils are found to add to the Hominid family tree
    • Most fossils of early humans are found in Africa and lower Asia
    • Most well understood members include genus Australopithecus (extinct) and genus Homo
    • Solve the Riddle of the Bones
  • 51. Genus Australopithecus
    • First human ancestor to live on the ground and walk on two legs
      • As evidenced by the Laetoli footprints
    • Ape-like jaw
    • Small brain
    • Short stature
    • Found only in South and East Africa
  • 52. The Australopithecines
    • A. anamesis 4 MYA
    • A. afarensis 3.2 MYA (Finding “Lucy”)
    • A. africanus 2.5 MYA
    • A. robustus 2 MYA
    • A. boisei 2 MYA
  • 53. Genus Homo
    • More modern hominids that exhibited major evolutionary steps
      • Increased brain size
      • Use of tools
      • Use of fire
      • Use of shelter
      • Religion
      • Language and civilization
  • 54. Homo habilis “The Tool Man”
    • Approx. 2.5 MYA
    • Brain ½ size of modern human
    • First to make and use stone tools and weapons
  • 55. Homo erectus “The Upright Man”
    • Direct ancestor of modern humans
    • Widespread in Africa and Asia by 1 MYA
    • Evidence of use of shelter and fire
  • 56. Homo sapiens “The Wise Man”
    • Most likely evolved from H. erectus as early as 400,000 years ago
    • Greatly increased brain size
    • Consisted of 2 groups
      • Neanderthal
      • Cro-Magnon/modern H. sapiens
  • 57. Neanderthals
    • Found in Neander Valley in Germany
    • Fossils found throughout Europe, Middle East, and Asia from 150,000-30,000 years ago
    • Large bodies and brains
    • Evidenced painting, religion, complex social structure
    • “Cave man”
  • 58. Cro Magnons and Fully Modern Humans
    • First early modern H. sapiens appear about 130,000 years ago
    • Thinner bones, smaller jaws, higher skull with little or no brow ridge, and larger brains
    • Cave art shows complex religion and culture
    • Lived alongside Neanderthal for several thousand years, but eventually out-competed them
  • 59.