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Darwin. Biology I. Evolution. Process by which organisms change over time. Darwin. Sailed to Galapagoes Islands Father of Evolution Amazed by the variety of Finches, Turtles and Iguanas Hypothesis: Organisms change over time. 1831 set sail from England around the world on H.M.S. Beagle.

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  1. Darwin Biology I

  2. Evolution • Process by which organisms change over time.

  3. Darwin • Sailed to Galapagoes Islands • Father of Evolution • Amazed by the variety of Finches, Turtles and Iguanas • Hypothesis: Organisms change over time

  4. 1831 set sail from England around the world on H.M.S. Beagle

  5. Darwin’s Observations • Collect fossils around the world and compared them to modern species. • Some were similar to species alive now and some were completely different. • He questioned why so many species had become extinct and if they were related to living species.

  6. Galapagos Islands • Group of islands off the coast of South America • Islands are close together, but have different climates • Turtles on each island had different shells • Finch’s on each island had different beaks

  7. Origin of the Species • 25 years after Galapagoes Islands published his book • Origin of Species- Proposed natural selection caused evolution

  8. Summary of Darwin’s Theory • Individual organisms differ, some is due to genetics • Organisms produce more offspring than can survive, and many that are produced do not survive. • Those that do survive are in constant competition over resources.

  9. Summary of Darwin’s Theory • Each organism has unique advantages and disadvantages. Individuals that are best suited for the environment survive and reproduce. This passes the best traits for survival to the new generation. • Species alive today are descendents from a past species.

  10. Jean-Baptiste Lamarck • French Naturalist • One of the 1st scientists to recognize things changed over time & species descended from other species • 1809, Darwin was born and Lamarck published his hypotheses: • By selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime. These traits would then be passed on to their offspring…over time this is how species changed.

  11. Lamarck • Before Darwin-- believed organisms change over time • Believed organisms lost or gained certain traits over time– pass favorable traits to offspring

  12. Tendency Toward Perfection • Lamarck thought that organisms have a tendency to develop towards complexity and perfection…so they continually change to make them live more successfully. • EX: Birds urge to fly and over time…their wings grew in size to be used for flying

  13. Use & Disuse • Lamarck thought organisms can change the size/shape of organs by using their bodies a different way • EX: Birds use front limbs more so they could use it them for flying

  14. Inheritance of Acquired Traits • Lamarck thought acquired traits could be inherited by the next generations • EX: Bigger front limbs on birds to use for flying…passed down to offspring • EX: If you workout and have big muscles…so will your children

  15. Disproven Theories • Lamarck’s theories have been disproven…but at the time these scientists developed these theories they knew very little about genetics and how traits are passed on from generation to generation.

  16. Survival of the Fittest • Organisms with the best adaptations—survive to reproduce • Natural Selection- only the most adapted organisms will survive • Natural selection changes a population over many successive generations-NOT AN INDIVIDUAL • Changes that increase a species fitness

  17. Struggle for existence • Organisms compete to obtain food and living space • Predators that are faster or prey with good camouflage has better chance of survival

  18. Natural Selection • Fitness- ability to reproduce and survive in environment • Adaptation- inherited characteristics that increase chance of survival • Beaks on finches, porcupine quills

  19. Genetic Variation • Genetic variation- variations in genes from parent to offspring • Some cows produce more milk than others • Some horses faster than others

  20. Artificial Selection • Artificial Selection is where nature provides a variety of off spring and humans select the variations they like.

  21. Descent with Modification • Living species descended with changes from other species over time • Common desent- all species come from a common ancestor

  22. Evidence of Evolution • Fossil record • Geographic distribution • Animals in same environments develop similar features

  23. Evidence of Evolution • Homologous body structures- structures that have different mature forms but develop from same embryonic tissue

  24. Evidence of Evolution • Vestigial organs- structures that do not have a true function • Whale hip bone, Human appendix

  25. Pics of Vestiges! Tailbones! Femur and Pelvis in a Whale!

  26. Evidence of Evolution • Embryology- early stages of embryos in organisms look the same Here you are! How Cute?!

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