1. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Chapter 26 The Tree of Life: An Introduction to Biological Diversity

2. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

3. Concept 26.1: Conditions on early Earth made the origin of life possible Chemical and physical processes on early Earth may have produced very simple cells through a sequence of stages: 1. Abiotic synthesis of small organic molecules 2. Joining of these small molecules into polymers 3. Packaging of molecules into “protobionts” 4. Origin of self-replicating molecules

4. LE 26-2 Water vapor CH 4 NH 3 H2H2 Electrode Condenser Cold water Cooled water containing organic molecules Sample for chemical analysis H2OH2O

5. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Video: Hydrothermal Vent Video: Hydrothermal Vent Video: Tubeworms Video: Tubeworms

6. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Protobionts Protobionts are aggregates of abiotically produced molecules surrounded by a membrane or membrane-like structure Glucose-phosphate Phosphorylase Amylase Starch Maltose Phosphate Simple metabolismSimple reproduction 20  m

7. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Concept 26.2: The fossil record chronicles life on Earth Fossil study opens a window into the evolution of life over billions of years Methods of Dating Fossils: Relative Radiometric

8. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings How Rocks and Fossils Are Dated Sedimentary strata reveal the relative ages of fossils

9. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Index fossils are similar fossils found in the same strata in different locations Video: Grand Canyon Video: Grand Canyon

10. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Index Fossils

11. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The absolute ages of fossils can be determined by radiometric dating The magnetism of rocks can provide dating information – Magnetic reversals of the magnetic poles leave their record on rocks throughout the world

12. LE 26-7 1 Accumulating “daughter” isotope Remaining “parent” isotope 2 1 4 1234 1 8 1 16 Ratio of parent isotope to daughter isotope Time (half-lives)

13. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The geologic record is divided into three eons: – Archaean – Proterozoic – Phanerozoic boundaries marked by mass extinctions seen in the fossil record Lesser extinctions mark boundaries of many periods within each era

14. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

15. Phanerozoic Eon

16. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Phanerozoic Eon

17. Millions of years ago 600500400300200100 Permian mass extinction 100 80 60 40 20 0 Extinction rate Cretaceous mass extinction 0 2,500 2,000 1,500 1,000 500 0 Neogene Proterozoic eon CambrianOrdovicianSilurianDevonianCarboniferousPermianTriassicJurassicCretaceousPaleogene PaleozoicMesozoic Ceno- zoic Number of families ( ) Extinction rate ( ) Number of taxonomic families

18. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Permian extinction killed about 96% of marine animal species and 8 out of 27 orders of insects – It may have been caused by volcanic eruptions The Cretaceous extinction doomed many marine and terrestrial organisms, notably the dinosaurs – It may have been caused by a large meteor impact

19. LE 26-9 NORTH AMERICA Chicxulub crater Yucatán Peninsula

20. LE 26-10 Land plants Animals Paleozoic Meso- zoic Ceno- zoic Origin of solar system and Earth 41 23 Multicellular eukaryotes Single-celled eukaryotes Prokaryotes Atmospheric oxygen Proterozoic Eon Archaean Eon Humans Billions of years ago

21. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Concept 26.3: As prokaryotes evolved, they exploited and changed young Earth The oldest known fossils are stromatolites, rocklike structures composed of many layers of bacteria and sediment Stromatolites date back 3.5 billion years ago

22. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

26. Photosynthesis and the Oxygen Revolution Oxygenic photosynthesis probably evolved about 3.5 billion years ago in cyanobacteria

27. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Effects of oxygen accumulation in the atmosphere about 2.7 billion years ago: – Posed a challenge for life – Provided opportunity to gain energy from light – Allowed organisms to exploit new ecosystems

28. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The First Eukaryotes The oldest fossils of eukaryotic cells date back 2.1 billion years

29. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Endosymbiotic Origin of Mitochondria and Plastids The theory of endosymbiosis proposes that mitochondria and plastids were formerly small prokaryotes living within larger host cells

30. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Key evidence supporting an endosymbiotic origin of mitochondria and plastids: – Similarities in inner membrane structures and functions – Both have their own circular DNA

31. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Colonial Connection The first multicellular organisms were colonies, collections of autonomously replicating cells

32. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The “Cambrian Explosion” Most of the major phyla of animals appear in the fossil record of the first 20 million years of the Cambrian period Two animal phyla, Cnidaria and Porifera, are somewhat older, dating from the late Proterozoic Millions of years ago 600500400300200100 Permian mass extinction 100 80 60 40 20 0 Extinction rate Cretaceous mass extinction 0 2,500 2,000 1,500 1,000 500 0 Neogene Proterozoic eon CambrianOrdovicianSilurianDevonianCarboniferousPermianTriassicJurassicCretaceousPaleogene PaleozoicMesozoic Ceno- zoic Number of families ( ) Extinction rate ( ) Number of taxonomic families

33. LE 26-17 500 Early Paleozoic era (Cambrian period) Millions of years ago 542 Late Proterozoic eon SpongesCnidariansEchinodermsChordatesBrachiopodsAnnelidsMolluscsArthropods

34. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Colonization of Land by Plants, Fungi, and Animals Plants, fungi, and animals colonized land about 500 million years ago Millions of years ago 600500400300200100 Permian mass extinction 100 80 60 40 20 0 Extinction rate Cretaceous mass extinction 0 2,500 2,000 1,500 1,000 500 0 Neogene Proterozoic eon CambrianOrdovicianSilurianDevonianCarboniferousPermianTriassicJurassicCretaceousPaleogene PaleozoicMesozoic Ceno- zoic Number of families ( ) Extinction rate ( ) Number of taxonomic families

35. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Continental Drift North American Plate Eurasian Plate Philippine Plate Indian Plate Arabian Plate Australian Plate Antarctic Plate African Plate Scotia Plate South American Plate Nazca Plate Pacific Plate Cocos Plate Juan de Fuca Plate Caribbean Plate

36. LE 26-19 Volcanoes and volcanic islands Trench Oceanic ridge Oceanic crust Subduction zone Seafloor spreading

37. LE 26-20 By about 10 million years ago, Earth’s youngest major mountain range, the Himalayas, formed as a result of India’s collision with Eurasia during the Cenozoic. The continents continue to drift today. By the end of the Mesozoic, Laurasia and Gondwana separated into the present-day continents. By the mid-Mesozoic Pangaea split into northern (Laurasia) and southern (Gondwana) landmasses. At the end of the Paleozoic, all of Earth’s landmasses were joined in the supercontinent Pangaea. 0 65.5 135 251 Millions of years ago Cenozoic Mesozoic Paleozoic North America Eurasia Africa India South America Madagascar Australia Antarctica Laurasia Gondwana Pangaea

38. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Previous Taxonomic Systems Early classification systems had two kingdoms: plants and animals Robert Whittaker proposed five kingdoms: Monera, Protista, Plantae, Fungi, and Animalia

39. LE 26-21 PlantaeFungiAnimalia Protista Monera Eukaryotes Prokaryotes

40. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Reconstructing the Tree of Life: A Work in Progress The five kingdom system has been replaced by three domains: Archaea, Bacteria, and Eukarya Each domain has been split into kingdoms

41. LE 26-22a Chapter 27Chapter 28 ProteobacteriaChlamydiasSpirochetesCyanobacteria Gram-positive bacteriaKorarchaeotes Euryarchaeotes, crenarchaeotes, nanoarchaeotes Diplomonads, parabasalidsEuglenozoans Alveolates (dinoflagellates, apicomplexans, ciliates) Domain Archaea Universal ancestor Domain Bacteria Domain Eukarya Stramenopiles (water molds, diatoms, golden algae, brown algae) Cercozoans, radiolarians Red algae Chlorophytes Charophyceans

42. LE 26-22b Chapter 29 Bryophytes (mosses, liverworts, hornworts) Plants Fungi Animals Chapter 30Chapter 28 Seedless vascular plants (ferns)Gymnosperms Angiosperms Amoebozoans (amoebas, slime molds) Chytrids Chapter 31 Zygote fungi Arbuscular mycorrhizal fungi Chapter 32Chapters 33, 34 Sac fungiClub fungi Choanoflagellates Sponges Cnidarians (jellies, coral) Bilaterally symmetrical animals (annelids, arthropods, molluscs, echinoderms, vertebrates)