1. Course web site www.clas.ufl.edu/users/mcmack/2008

2. Module 1: Evolution MonthDayTopic Aug28History of life on Earth 30Timeline construction Sept1Theory of evolution 4Holiday 6Evidence for evolution 8Mechanisms of evolution I 11Mechanisms of evolution II 13Speciation

3. Outline 1.What is life? 2.How might it have arisen? 3.What has happened since then?

4. Time Cosmological Geological Evolutionary Ecological Physiological

5. 4.5 billion years ago, the earth was born

7. Life is...what?

8. Life shares... 1. Chemical composition – CHON(SP) Carbon Hydrogen Oxygen Nitrogen Sulfur Phosphorus Iron, Zinc, Calcium, Sodium...

9. Life shares... 2. Biochemistry in liquid water –Proteins –Lipids –Carbohydrates –Nucleic acids

10. Life shares... 3. Use of matter and energy –Energy stored and released by breaking chemical bonds –Autotrophs –Heterotrophs –Metabolism –Enzymes –Homeostasis

11. Life shares... 4. Cells –Membranes –Cytoplasm –Organelles –Nucleus A prokaryote cell...

12. Life shares... 5. Reproduction –Heredity –Variation

13. Life shares... 6. Ecology!!!!!

14. Life shares... 1.Chemical composition-CHON(SP) 2.Biochemistry 3.Use of matter and energy 4.Cells 5.Reproduction 6.Ecology

15. How did life start?

17. Causal mechanism

18. The biogenesis paradox Life arises from life... But what about the first organisms?

19. How did life start? In a very different earth environment –Reducing atmosphere—No O 2 ! –Lots of H 2 O –Lightening, volcanoes, ultraviolet rays

20. The primordial soup hypothesis 1.Abiotic synthesis of simple organic molecules

22. The primordial soup hypothesis 1.Abiotic synthesis of simple organic molecules 2....complex organic molecules

23. The primordial soup hypothesis 1.Abiotic synthesis of simple organic molecules 2....complex organic molecules 3.Origin of self-replicating molecules

24. The primordial soup hypothesis 1.Abiotic synthesis of simple organic molecules 2....complex organic molecules 3.Origin of self-replicating molecules 4.Formation of pre-cells

25. The big leap From pre-cells to life... Lots of time for natural selection

26. Life first appears in the fossil record about 3.8 billion years ago

29. Changes on Earth that have shaped life… Atmosphere (O 2, UV) Continental drift Climate Volcanoes Extraterrestrial bombardment

32. History has been punctuated by mass extinctions

33. 1 st mass extinction 440 mya: ~75% of species disappear Sudden global cooling? Predatory arthropod

34. 2 nd mass extinction 370 mya: ~75% of species disappear Continental collision or global climate change?

35. 3 rd mass extinction 245 mya: ~96% of species disappear The greatest event of all time! Extraterrestrial impact?

36. 4 th mass extinction 210 mya: ~65% of species 5 th mass extinction 65 mya: ~76% of species Extraterrestrial impact or volcanism?

37. The 6 th mass extinction... Last 10,000 years –30% of earth’s species gone by year 2100