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Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh Edition Solomon Berg Martin Chapter 20 The Origin and Evolutionary History of Life.

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Presentation on theme: "Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh Edition Solomon Berg Martin Chapter 20 The Origin and Evolutionary History of Life."— Presentation transcript:

1 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh Edition Solomon Berg Martin Chapter 20 The Origin and Evolutionary History of Life

2 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Conditions on early Earth 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

3 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Requirements for chemical evolution to produce life Absence of oxygen Energy Chemical building blocks Sufficient time

4 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Prebiotic soup hypothesis Molecules formed near the Earths surface Sugars, nucleotides, amino acids formed spontaneously

5 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Miller-Urey experiment

6 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Iron-sulfur world hypothesis Organic molecules formed at hydrothermal vents on the ocean floor Laboratory simulations show catalyst effects of iron and nickel sulfides

7 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Origin of cells Spontaneous assembly of small organic molecules into macromolecules Protobionts similar to cells –Binary fission –Homeostasis –Catalytic activity

8 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Microspheres – a type of protobiont

9 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Microspheres Formed from water and polypeptides Electric gradient on surface Selective permeability

10 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life RNA world 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

11 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Directed evolution Large pool of RNA molecules with different sequences Selected for ability to catalyze a reaction Amplify / mutate / repeat

12 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Directed evolution

13 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life In the RNA world, ribozymes catalyzed protein synthesis DNA formed from double strands of RNA DNA more stable than RNA

14 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life The first cells Heterotrophs that feed on organic molecules Anaerobic fermentation process to obtain energy

15 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Autotrophs Selected after organic molecule food stock became scarce Photosynthetic production of organic molecules Cyanobacteria split water molecules and released oxygen

16 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Aerobes More efficient energy production using oxygen respiration Significant oxygen in the atmosphere by 2 bya

17 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Formation of the ozone layer Ultraviolet radiation forms O 3 from O 2 in the upper atmosphere Prevents UV from reaching Earth Decreased mutagenesis Enabled organisms to live in surface waters and on land

18 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Ozone formation

19 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Eukaryotes arose from prokaryotes Endosymbiont theory –Mitochondria and chloroplasts derived from prokaryotes –Ingested but not digested –Reproduced along with host cell

20 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Endosymbiont theory

21 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Geological eras Paleozoic –543 mya mya Mesozoic –251 mya - 65 mya Cenozoic –65 mya - present

22 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Using a clock to represent biological time

23 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Precambrian time Before 543 mya Bacteria Protists Fungi Simple multicellular animals

24 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Cambrian explosion All animal phyla established Many new body plans Bizarre, extinct phyla

25 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Ordovician period Shallow seas covered land Cephalopods Coral reefs Jawless fishes

26 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Silurian period Jawed fishes Terrestrial plants Air-breathing animals

27 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Devonian period Bony fishes Amphibians Wingless insects All major plant groups except for flowering plants established

28 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Carboniferous period Swamp forests Reptiles Winged insects

29 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Carboniferous forest

30 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Permian period Therapsids –Reptilian ancestors of mammals Seed plants dominant Ended the Paleozoic with the greatest mass extinction –90% of marine species –70% of land vertebrates

31 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Mesozoic Era

32 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Triassic period Thecodonts –Ancestors of dinosaurs and birds Pleiosaurs and ichthyosaurs Pterodonts First mammals –Small insectivores

33 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Jurassic and Cretaceous periods Saurischians –Ancestors of lizards Ornithischians –Ancestors of birds Ended with mass extinction caused by a meteorite impact

34 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Saurischians

35 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Ornithischians

36 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Cenozoic Era

37 Copyright © 2005 Brooks/Cole Thomson Learning Biology, Seventh EditionCHAPTER 20 The Origin and Evolutionary History of Life Tertiary period Diversification of flowering plants, birds, insects, mammals Quaternary period Genus Homo Large mammals


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