2. Speciation – process by which new species arrive. Macroevolution – evolution on a grand scale Adaptive radiation - evolution of many diversely adapted species from a common ancestor

3. Introduction to the History of Life The Origin of Life Organic (Chemical) Evolution Major Lineages of Life

5. Conditions on early Earth Four Stage Hypothesis of Origin RNA, the first genetic material Natural selection’s role – directed evolution

6. Four Stage Hypothesis of Origin 1.Abiotic synthesis of building blocks 2.Production of organic polymers 3.Origin of self-replicating molecules (making inheritance possible) 4.Protobionts are packaged with material that makes internal chemistry different from surroundings

7. Age of Earth is ~4.6 billion years Atmosphere had little free O 2 Included CO 2, H 2 O, CO, H 2, N 2 Maybe also NH 3, H 2 S, CH 4 Lack of oxygen meant that the environment would have “reducing” nature

8. Requirements for chemical evolution to produce life Absence of oxygen Energy Chemical building blocks Sufficient time

9. 1920s – A.I. Oparin and J.B.S. Haldane 1953 – Stanley Miller and Harold Urey test the Oparin-Haldane hypothesis

10. Miller-Urey experiment

11. Other hypotheses: “hot rocks” – organic molecules are concentrated as water evaporates from geothermal activity Clay – clay contains charged particles which retains organics when runoff is collected Deep sea vents produce many inorganic catalysts that could aid in the making of polymers

12. Self-replicating RNA molecules Function as both enzyme and substrate for replication Ribozyme is enzymatic RNA First step in evolution of the DNA / RNA / protein system

13. Separate internal environment from external surroundings by a biological membrane As protobionts became more similar to cells they would have evolved the following: Binary fission Homeostasis Catalytic activity

15. Microspheres – a type of protobiont

16. Microspheres Formed from water and polypeptides Electric gradient on surface Selective permeability Liposomes Lipids organized into a molecular bilayer Selective permeability Behave dynamically – grow, split, etc.

17. Large pool of RNA molecules with different sequences Selected for ability to catalyze a reaction Amplify / mutate / repeat

18. Directed evolution

19. In the RNA world, ribozymes catalyzed protein synthesis DNA formed from double strands of RNA DNA more stable than RNA

20. Heterotrophs that feed on organic molecules Anaerobic fermentation process to obtain energy

22. Organic molecule food stock became scarce Photosynthetic production of organic molecules Cyanobacteria evolved later and could split water molecules which released oxygen

23. More efficient energy production using oxygen respiration Significant oxygen in the atmosphere-2 bya

24. Ultraviolet radiation forms O 3 from O 2 in the upper atmosphere Prevents UV from reaching Earth Enabled organisms to live in surface waters and on land

25. Ozone formation

26. Endosymbiont theory Mitochondria and chloroplasts derived from prokaryotes Ingested but not digested Reproduced along with host cell

27. Endosymbiont theory

28. Linnaeus’ two-kingdom system Plant (non-moving) and Animal (moving) Robert Whittaker’s five-kingdom system Plantae, Animalia, Fungi, Protista, Monera Carl Woese’s three-domain system Eukarya, Archaea, Bacteria

30. Glaciations; mammals increased; humans Mammals diversified; grasses Aquatic reptiles diversified; flowering plants; mass extinction Dinosaurs diversified; birds Dinosaurs; small mammals; cone-bearing plants Reptiles diversified; seed plants; mass extinction Reptiles; winged insects diversified; coal swamps Fishes diversified; land vertebrates (primitive amphibians) Land plants; land animals (arthropods) Aquatic arthropods; mollusks; vertebrates (jawless fishes) Marine invertebrates diversified; most animal phyla evolved Anaerobic, then photosynthetic prokaryotes; eukaryotes, then multicellular life Cenozoic Mesozoic Paleozoic Precambrian Time Quaternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian 1.8–present 65–1.8 145–65 208–145 245–208 290–245 363–290 410–363 440–410 505–440 544–505 650–544 Key EventsEraPeriodTime (millions of years ago)