1. Evolution Essential ?s How & why have species changed with time? What is the benefit & value of evolution? How can the theory of evolution be applied to today? What evidence & thought have contributed to the theory of evolution?

2. Evolution Change in genetic make-up over time Process by which modern organisms have descended from ancient organisms

3. The History of the Development of Evolutionary Thought

4. 1 st Hypothesis Use & Disuse Jean – Baptiste Lamark 1809 French naturalist

5. Tendency Towards Perfection & Complexity organisms continually change to become better adapted to their environment & improve survival Use & Disuse of Organs structure that are used frequently will become larger and be more developed during a lifetime structures not used will become weaker or disappear (vestigial organs) during a lifetime Inheritance of Acquired Traits newly acquired traits can be passed on to offspring

6. Evaluation of Lamark’s Theory Incorrect because….. acquired traits (those gained during an organisms lifetime) are NOT inherited acquired behaviors CANNOT develop heritable characteristics Correct because…. organisms adapt to their environment overtime to increase survival

7. 2 nd Hypothesis Natural Selection Charles Darwin 1831

8. Voyage on the H.M.S. Beagle The Trip around the World Observed many various organisms Researched their patterns of diversity Studied living organisms & fossils Concluded that the earth is constantly changing

9. The Galapagos Islands Most influential location to Darwin’s development of the theory of evolution 13 small islands off the West coast of South America by Ecuador Close proximity Extremely diverse climates & environments Isolated from each other

10. Organisms on each island vary greatly in characteristics to be specialized & better adapted to their diverse environments

11. Darwin’s Theory of Evolution Published in 1931 “The Origin of Species”

12. Natural Selection Organisms varying in inheritable characteristics (mechanics of genetics was unknown at this time!) Large population size causes competition for resources & restricts survival rate

13. Natural Selection Organisms with traits that are better “fitted” or adapted to their environment survive and reproduce more successfully passing on their superior genes to the next generation

14. Fitness resulting adaptations that increase the survival of an organism Adaptations any inherited characteristic that increases an organism’s survival “Survival of the Fittest”

15. Descents with Modification Over many successive generations: pressures of natural selection change traits of a population increase overall fitness of the population Species evolve: differences in structures & niches resulting in the formation of a new species remaining related to each other by a common ancestor

16. 3 Types of Natural Selection

17. Stabilizing Natural Selection Nature eliminates both extreme traits Nature favors average traits Graph narrows increasing the number of species with the average trait

18. Directional Natural Selection Nature eliminates only 1 extreme trait The other extreme trait is favored Graph & population diversity shifts toward favored trait

19. Distributive Natural Selection Nature eliminates the average trait & favors the extreme traits Graph & population diversity shifts towards the 2 extreme traits Possibly leading to creating 2 new species

21. Finches of the Galapagos Islands Darwin’s most famous discoveries came from his observations on the variations of finch species on the Galapagos Islands which had extremely diverse and extensive gene pools, supporting his theory of evolution

22. All of the Finches from the Galapagos Island evolved from the same founder species The Finches were separated to different islands over several years On each island they experience different natural pressures

23. Finches on each island developed variations to make them better adapted to their different environments of each island Eventually the Finches became specialized and different from each other becoming separate & new species on each island

24. Finch’s of the Galapagos Islands