2. The Evolution of Evolution 4 Why are there so many species of life on Earth? 4 Where did all the species come from? 4 Why did some species go extinct? 4 _________________________________

3. Time Line of Ideas 1) Creationism: supernatural being created each type of species at the beginning of the world modern organisms are unchanged from the original ancestors supernatural, not a natural explanation (not science)

4. 2) Plato / Aristotle (400-300 B.C.) species are unchanging forms there is an increasing degree of perfection between species with humans at the top

5. 3) Leclerc (Comte de Buffon) (1707-1788) original creation provided a few species which gave rise to modern species unconvincing because: 1. no mechanism for change 2. not enough time for it occur (Earth believed to be 4000-6000 yrs. old)

6. 4) Cuvier (1769-1832) many species originally created subsequent catastrophes produced rock, destroying / fossilizing species, therefore, modern species are survivors of catastrophes Why are there no fossils of modern organisms in the oldest rocks?

7. 5) Agassiz (1807-1873) a new creation occurred after each catastrophe, therefore, at least 50 separate catastrophes and creations

8. 6) Hutton (1726-1797) & Lyell (1797-1875) geologists who developed uniformitarianism: natural processes produced Earth’s features [Ex: layers of sedimentary rock produced by effects of floods, volcanoes, wind, erosion, etc. The results occur very slowly, so Earth must be VERY old provided time frame for organisms to change, but still no mechanism of change

9. 7) Lamarck (1744-1829) “Inheritance of Acquired Characteristics” organisms can modify their bodies through use or disuse of structures or organs and pass those modifications on to offspring

10. 8) Mid 1800’s similarities between fossil forms and modern day species could be explained if present day species evolved from pre- existing ones BUT HOW??

11. Charles Darwin (1809-1882) 4 5 year, world wide journey as a naturalist aboard H.M.S. Beagle (1831-1836) 4 Witnessed a diversity of plants, animals and landscapes never seen before © Encarta

12. Voyage of H.M.S. Beagle © Darwin and the Beagle

13. How were we formed? © Dorling Kindersley Nature http://volcano.und.nodak.edu/vwdocs/volc_imag es/img_volc_darwin.html

14. Why are our trunks so tall? (© Audesirk & Audesirk)

15. Why do we have wings? King Penguins A colony of king penguins gathers on South Georgia, an island near the southern tip of South America. King penguins may stand about 1 m (about 3.3 ft) tall, making them the second-largest penguin species. © Encarta

16. Why are there so many varieties of us? © Encarta

17. Whoever heard of marine iguanas? http://www.leler.com/galapagos/

18. What influenced Darwin? 4 Huge variety of species, some with subtle but important differing features 4 Increasing complexity of organisms through the fossil record 4 Earth is very old (Hutton & Lyell) 4 Populations do not grow unchecked; more offspring are produced than survive (Malthus) 4 What determines who lives & who dies?

19. The Theory of Evolution by Natural Selection 4 Populations have the potential to increase at a geometric rate, but in the short run the number of individuals in a population remains fairly constant 4 The conditions of life are limited 4 Most environments change constantly throughout geologic time 4 Only a fraction of offspring in a population will live to reproduce

20. 4 Individuals in a population are not all the same: some have variable traits that can be inherited 4 The “struggle for existence” determines which traits are favorable or unfavorable by determining the success of the individual who possesses the traits 4 Individuals with favorable traits produce more offspring than those with unfavorable traits

21. 4 Natural selection causes the accumulation of favorable traits and the loss of unfavorable traits to the extent that a new species may arise

22. 4 Life evolved from one kind or a few “simple” kinds of organisms 4 Each species arose from another species that preceded it in time 4 Each species originated in a single geographic location 4 The greater the similarity between two groups of organisms, the closer their relationship and the closer in geologic time is their common ancestral group The Theory of Evolution from a Common Ancestor

23. 4 Extinction of old species is a consequence of the production of new species or of environmental change 4 Once a species has gone extinct, it never reappears 4 Evolution continues today in generally the same manner as during preceding geologic eras 4 The geologic record is very incomplete

24. Evolution Today 4 A change in gene frequency within a population over time (population = all the individuals of a species living in a given area) 4 Species = similar organisms living in an area that can interbreed under natural conditions

25. 4 Peppered moths (Light & dark genes) 4 Antibiotic resistance by bacteria 4 Pesticide and herbicide resistance by insects and plants © Encarta