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Evolution

Evolution. (Reference: Chapters 14,15 & 16). Evolution How does it happen? What is the evidence? What IS it really?. 1 st Define Evolution!. 1. the descent of modern organisms, with modification, from preexisting life-forms.

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Evolution

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  1. Evolution (Reference: Chapters 14,15 & 16)

  2. Evolution How does it happen? What is the evidence? What IS it really?

  3. 1st Define Evolution! • 1. the descent of modern organisms, with modification, from preexisting life-forms. • 2. all organisms are related by common ancestry and have changed over time • 3. any change in the genetic makeup in a population from one generation to the next • Hmmmmmmmm….OK

  4. A (not so) short list of things to keep in mind as we study Evolution: • Evolution is a well supported theory about how organisms change • Is NOT concerned with the origin of life... (it deals only with the origin of species). • A theory in science is DIFFERENT than a theory in everyday life or other disciplines • http://www.pbs.org/wgbh/evolution/library/11/2/e_s_1.html

  5. 4. An individual organism does not evolve… a POPULATION does 5. Humans did not evolve from current species of monkeys or apes. We share a common ancestor from a LONG LONG time ago. • Different human species coexisted on Earth in the past

  6. We have observed (over and over again) changes in populations over time. • Experiments and through breeding animals 7. Evolution does not have a goal or “give” an organism what it needs 8. Darwin did not come up with evolution, he came up with how it might happen or the mechanism called NATURAL SELECTION -. Natural selection = Evolution

  7. Evolution is NOT a belief – it is based on science, NOT faith. • It does not set out to prove or dispute God or any creator • Evolution is STILL OCCURRING • That all species are related and came from one ancestral species

  8. 12. is NOT an accidental or random process...(there are built-in limited options and selective aspects; even mutations are influenced by environmental factors). • Its complex patterns are just as natural as the randomly generated and diverse patterns of snowflakes and crystals. • 13. It does not suggest whether species are “better” or “higher order” than others.

  9. 14. Species change over millions of years and can become new species or split into separate species • 15. That the earth is much older than biblical accounts

  10. There is very little scientific debate Scientists debate the details of evolution but there is overwhelming consensus that evolution does occur There is a lot ofevidence

  11. Currently there is a debate to teach creationism along with evolution.

  12. But science teachers are not required to teach other belief systems

  13. Many religions accept evolution. • The ones that do not accept evolution tend to hold major misconceptions which has lead to the controversy.

  14. Did Darwin figured it all out by himself?… NO. Each bar represents the life span of a scientist that played a key role in the development of modern evolutionary biology.

  15. The First Person to Suggest Evolution was… NOT Charles Darwin, but Jean Baptiste Lamarck revived a theory that existed for thousands of years Suggested species change over time and can become new species BUT he had no evidence, and his hypothesis did not properly explain how evolution could occur

  16. Charles Darwin Proposed a well-thought out, coherent, well-researched hypothesis Was scared to publish for many years. Alfred Wallace published at the same time but Darwin’s version was more complete so he gets all the credit

  17. Who was Charles Darwin? (1809-1882) http://www.pbs.org/wgbh/evolution/library/11/2/e_s_2.html A. Failed as a doctor and a minister! B. 1831 – he becomes the naturalist aboard the H.M.S. Beagle for a 5 year mapping expedition to South America. 1. naturalist: includes collecting plant & animal specimens and documenting wildlife at all stops on journey.

  18. Ended up in… 4.)The Galapagos Islands – an island chain west of Ecuador. a.) Each island has slight variations in climate as well as plant and animal life.

  19. b.) Animals such as tortoises and birds called finches from different islands had slightly different body shapes and traits. Upon further study, Darwin and others determined that they were in fact different species! i.) Species: a group of similar organisms that can breed and produce viable offspring

  20. c.) Darwin infers: an ancestral species of finch arrived on the islands from the mainland and spread from island to island. Each island species diverged over time into separate species based on the specific environment of each island. Which leads to his mechanism…Natural selection

  21. Let’s compare Darwin & Lamark • Classwork! • Comparison of evolutionary mechanisms! • Complete the ws quietly and by yourself at your table. • You will have 21 minutes or less or more depending on your level of focus. • When we are all done we will discuss the answers. Please remain quiet if you finish early.

  22. Jean – Baptiste Lamarck. In 1809, published a theory on evolution : a.) Traits are developed out of “need” b) Through use/disuse characteristics are developed. c) An individual evolves in it’s lifetime & passes that trait to it’s children

  23. A.) This is wrong! Why? Organisms cannot pass on acquired traits. ex: A body builder does not have muscular babies B) ALSO an individual does not evolve, a population evolves.

  24. So… what did Darwin propose?2 Main Parts Species change over long periods of time Enough differences accumulate that new species form All species came from one common ancestor (this was a bit of a leap of faith on his part) Changes in the environment can cause populations to change over time… this is the HOW evolution occurs Descent with Modification Natural Selection

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