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THEORIES of Evolution.pptx

  1. MELC: Explain the occurrence of evolution Ms. Jeraldel Encepto Science 10 Teacher
  2. Theories of Evolution MELC: Explain the occurrence of evolution
  3. Theories of Evolution
  4. A long time ago, a small flock of sparrow-like birds called finches were blown out to sea by a fierce storm. They lost their bearings but flew on in search of the mainland, going further and further out to sea. At the point of exhaustion, 600 miles from home, they spotted a speck of land - an island in the middle of the sea. They were saved and could rest, drink and feed before returning home. But this island was perfect: it had abundant seeds and other food, plenty of shelter, nesting sites and (amazingly) no predators or other birds to compete with.
  5. Life was much harder on the mainland. There was no need for the birds to move on. Their numbers grew - until they became just a bit too numerous for the little island. Some found it hard to find enough food for themselves or their offspring, and young birds were driven away from areas where food was available. Some birds were forced to fly across the sea to nearby islands. There, they found new territories, also with no predators or other birds to compete with.
  6. As the plants and their seeds were just a little different on each island, some birds were better than others at finding and eating the new food sources. Birds which could break open fruits and eat the seeds survived well enough to produce lots of babies. Eventually, after a very long time, all the islands became occupied by these birds but the finches on each island were slightly different.
  7. 1. Explain why it is questionable that more than one flock of birds would find the islands in this way at the same time. 2. Suggest two possible reasons why there were no predators on the island. 3. Why were there no other birds to compete with? (see Q1) 4. Why might some finches survive better than others on the same food sources? 5. Why were the finches slightly different on each island?
  8. History of Evolutionary Thought Catastrophism (Werner/Cuvier)  States that the earth and geological events had formed suddenly, as a result of some great catastrophe.
  9. History of Evolutionary Thought Uniformitarianism (Hutton/Lyell)  Idea that the earth has always changed in uniform ways and that the present is the key to the past
  10. Theories of Evolution
  11. Jean-Baptiste Lamarck (1744-1829) Developed one of the first theories on how species changed Concluded that organisms of higher complexity had evolved from pre-existing, less complex organisms. Lamarck’s Theories on Evolution
  12. Jean-Baptiste Lamarck (1744-1829)  Lamarckism, a theory of evolution based on the principle that physical changes in organisms during their lifetime— such as greater development of an organ or a part through increased use—could be transmitted to their offspring. Lamarck’s Theories on Evolution
  13. Lamarck’s Theories on Evolution Theory of Need Theory of Use and Disuse Theory of Acquired Characteristics
  14. Lamarck’s Theories on Evolution
  15. Lamarck’s Theories on Evolution Organisms change because they need to. For an organism to evolve a structure, it must need the structure Theory of Need
  16. Lamarck’s Theories on Evolution
  17. Lamarck’s Theories on Evolution
  18. Lamarck’s Theories on Evolution
  19. Lamarck’s Theories on Evolution
  20. Lamarck’s Theories on Evolution
  21. Lamarck’s Theories on Evolution If you don’t use it, you lose it! Organisms develop specialized characteristics by the use and disuse of organs Theory of Use and Disuse
  22. Lamarck’s Theories on Evolution
  23. Lamarck’s Theories on Evolution If parent acquires a body structure during its lifetime, it could pass on that characteristic structure to its offspring. Theory of Acquired Characteristics
  24. 1. Petals on flowers 2. Corset 3. Frequent exercise 4. Tails of mice Disproving Lamarck
  25. Charles Darwin (1809-1882) Proposed an entirely different mechanism to account for the evolution of species His theory of evolution by natural selection became the foundation of modern evolutionary studies Theory of Natural Selection
  26. Theory of Natural Selection HMS Beagle
  27. Theory of Natural Selection
  28. Theory of Natural Selection
  29.  Darwin was able to see 13 varieties of finches, which varied in size & shape, from island to island.  It took him 20 years to organize the data. Darwin’s finches
  30. Theory of Natural Selection
  31.  Darwin presented his theory of evolution based on natural selection The Origin of Species
  32. Alfred Russel Wallace (1823-1913) Theory of Natural Selection
  33. Follow the Track Explain the Theory of Natural Selection.
  34.  Individuals within a population with the most favorable traits for an environment survive and pass on those traits. Natural Selection SURVIVAL OF THE FITTEST!
  35.  Organisms tend to over reproduce Theory of Natural Selection Species Overproduction
  36.  There is a struggle of existence and the survival of the fittest  Living space and food are limited Theory of Natural Selection Competition
  37.  No two individuals are the same  Plants and animals of the same species differ in size, strength and adaptive structures Theory of Natural Selection Variation
  38.  It is a process of becoming better suited to the environment.  It improves an organism’s chance of survival Theory of Natural Selection Adaptation
  39.  Environment selects organisms that survived to be the parents of succeeding generations Theory of Natural Selection Natural Selection
  40.  Favorable adaptations gradually accumulate in the species and unfavorable ones disappear Theory of Natural Selection Speciation
  41. Darwin’s Giraffes
  42. Darwin’s Giraffes
  43. Darwin’s Giraffes
  44. Darwin’s Giraffes
  45. Darwin’s Giraffes
  46. Lamarck’s Giraffes VS Darwin’s Giraffes
  47.  Before the industrial revolution in Britain, most peppered moths were of the pale variety & were well camouflaged against the pale birch trees that they like to sit on. Theory of Natural Selection Peppered Moths
  48.  Airborne pollution mottled the birch tree bark with soot, and now the mutant black-peppered moths blended better against the darkened bark, while the white variety became much more vulnerable to predators. Theory of Natural Selection Peppered Moths
  49. Theories of Evolution
  50. Theories of Evolution

Notes de l'éditeur

  1. Catastrophism was a theory developed by Georges Cuvier based on paleontological evidence in the Paris Basin. Cuvier was there when he observed something peculiar about the fossil record. Instead of finding a continuous succession of fossils, Cuvier noticed several gaps where all evidence of life would disappear and then abruptly reappear again after a notable amount of time. Cuvier recognized these gaps in the fossil succession as mass extinction events. This led Cuvier to develop a theory called catastrophism. Catastrophism states that natural history has been punctuated by catastrophic events that altered that way life developed and rocks were deposited.
  2. Procedure: Observe the set of footprints in the diagram. Try to tell a story about the different events. Predict what can probably happen at the end of the diagram In Diagram 1, how many sets of footprints are there? Based on the size of footprints, describe the organisms. 2. In what directions are the footprints going? 3. Describe or predict what is happening in Diagram 3. In Diagram