Sealey evolution


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Sealey evolution

  1. 1. Correction of Evolution Misconception… Evolution = humans came from monkeys
  2. 2. Evolution really means… • CHANGE OVER TIME! • Think about it… – Over 4.6 Billion years there have been LOTS of changes – Life as we know it has survived despite many obstacles – How? • Life ADAPTS to survive!
  3. 3. “Evolve” Means Earth has changed over time is to Change Over Time • The belief that life on quite old • To be considered science, this belief requires a great deal of evidence
  4. 4. 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.
  5. 5. 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.
  6. 6. 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 is the process by which living things change and diversify over time
  7. 7. 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
  8. 8. 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
  9. 9. Anatomy: Homologous Structures • Similar parts of different organisms, often quite dissimilar in purpose, that developed from the same ancestral body parts. • Divergent evolution
  10. 10. 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
  11. 11. Natural Selection and Speciation
  12. 12. 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.
  13. 13. 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
  14. 14. The Galapagos Archipelago
  15. 15. Land Iguana Marine Iguana
  16. 16. Evolution Through Natural Selection • There is variation in populations caused by genetics • 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.
  17. 17. 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