1. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings PowerPoint Lectures for Biology: Concepts and Connections, Fifth Edition – Campbell, Reece, Taylor, and Simon Lectures by Chris Romero Chapter 16 The Origin and Evolution of Microbial Life: Prokaryotes and Protists

2. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings How Ancient Bacteria Changed the World Mounds of rock found near the Bahamas –Contain photosynthetic prokaryotes

3. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Fossilized mats 2.5 billion years old mark a time when photosynthetic prokaryotes –Were producing enough O 2 to make the atmosphere aerobic Layers of a bacterial mat

4. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings EARLY EARTH AND THE ORIGIN OF LIFE 16.1 Life began on a young Earth Planet Earth formed some 4.6 billion years ago

5. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings The early atmosphere probably contained –H 2 O, CO, CO 2, N 2, and some CH 4 Volcanic activity, lightning, and UV radiation were intense Figure 16.1A

6. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Fossilized prokaryotes called stromatolites –Date back 3.5 billion years Figure 16.1B

7. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings A clock analogy tracks the origin of the Earth to the present day –And shows some major events in the history of Earth and its life Paleozoic Meso- zoic Ceno- zoic Humans Land plants Animals Multicellular eukaryotes Single-celled eukaryotes Origin of solar system and Earth 1 2 4 3 Proterozoic eon Archaean eon Billions of years ago Atmospheric oxygen Prokaryotes Figure 16.1C

8. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.2 How did life originate? Organic molecules –May have been formed abiotically in the conditions on early Earth

9. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings TALKING ABOUT SCIENCE 16.3 Stanley Miller’s experiments showed that organic molecules could have arisen on a lifeless earth Figure 16.3A

10. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Simulations of such conditions –Have produced amino acids, sugars, lipids, and the nitrogenous bases found in DNA and RNA Cooled water containing organic molecules Cold water Condenser Sample for chemical analysis H 2 O “Sea” Water vapor “Atmosphere” Electrode CH 4 NH 3 H2H2 Figure 16.3B

11. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.4 The first polymers may have formed on hot rocks or clay Organic polymers such as proteins and nucleic acids –May have polymerized on hot rocks

12. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.5 The first genetic material and enzymes may both have been RNA The first genes may have been RNA molecules –That catalyzed their own replication G A G G C G G G C C C A A A A U U U U G CU A UG C A U U CGGU U UG C A U A UG C A 1 2 Formation of short RNA polymers: simple “genes” Assembly of a complementary RNA chain, the first step in replication of the original “gene” Monomers Figure 16.5

13. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.6 Membrane-enclosed molecular cooperatives may have preceded the first cells RNA might have acted as templates for the formation of polypeptides –Which in turn assisted in RNA replication Self-replication of RNA Self-replicating RNA acts as template on which poly- peptide forms. Polypeptide acts as primitive enzyme that aids RNA replication. RNA Polypeptide Figure 16.6A

14. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Membranes may have separated various aggregates of self-replicating molecules –Which could be acted on by natural selection LM 650  Membrane Polypeptide RNA Figure 16.6B, C

15. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings PROKARYOTES 16.7 Prokaryotes have inhabited Earth for billions of years Prokaryotes are the oldest life-forms –And remain the most numerous and widespread organisms Colorized SEM 650  Figure 16.7

16. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.8 Bacteria and archaea are the two main branches of prokaryotic evolution Domains Bacteria and Archaea –Are distinguished on the basis of nucleotide sequences and other molecular and cellular features

17. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Differences between Bacteria and Archaea Table 16.8

18. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.9 Prokaryotes come in a variety of shapes Prokaryotes may be shaped as –Spheres (cocci) –Rods (bacilli) –Curves or spirals Colorized SEM 12,000  Colorized SEM 9,000  Colorized SEM 3,000  Figure 16.9A–C

19. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.10 Various structural features contribute to the success of prokaryotes

20. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings External Structures The cell wall –Is one of the most important features of nearly all prokaryotes –Is covered by a sticky capsule Colorized TEM 70,000  Capsule Figure 16.10A

21. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Some prokaryotes –Stick to their substrate with pili Colorized TEM 16,000  Pili Figure 16.10B

22. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Motility Many bacteria and archaea –Are equipped with flagella, which enable them to move Flagellum Plasma membrane Cell wall Rotary movement of each flagellum Colorized TEM 14,000  Figure 16.10C

23. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Reproduction and Adaptation Prokaryotes –Have the potential to reproduce quickly in favorable environments

24. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Some prokaryotes can withstand harsh conditions –By forming endospores TEM 34,000  Endospore Figure 16.10D

25. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Internal Organization Some prokaryotic cells –Have specialized membranes that perform metabolic functions Figure 16.10E Respiratory membrane Thylakoid membrane TEM 45,000  TEM 6,000 

26. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.11 Prokaryotes obtain nourishment in a variety of ways As a group –Prokaryotes exhibit much more nutritional diversity than eukaryotes

27. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Types of Nutrition Autotrophs make their own organic compounds from inorganic sources –Photoautotrophs harness sunlight for energy and use CO 2 for carbon –Chemoautotrophs obtain energy from inorganic chemicals instead of sunlight

28. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Heterotrophs obtain their carbon atoms from organic compounds –Photoheterotrophs can obtain energy from sunlight –Chemoheterotrophs are so diverse that almost any organic molecule can serve as food for some species Figure 16.11A

29. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Nutritional classification of organisms Table 16.11

30. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Metabolic Cooperation In some prokaryotes –Metabolic cooperation occurs in surface- coating colonies called biofilms Colorized SEM 13,000  Figure 16.11B

31. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.12 Archaea thrive in extreme environments— and in other habitats Archaea are common in –Salt lakes, acidic hot springs, deep-sea hydrothermal vents Figure 16.12A, B

32. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Archaea are also a major life-form in the ocean

33. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.13 Bacteria include a diverse assemblage of prokaryotes Bacteria are currently organized into several subgroups, including –Proteobacteria LM 13,000  Colorized TEM 5,000  Figure 16.13A, B

34. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings –Chlamydias –Spirochetes

35. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings –Gram-positive bacteria –Cyanobacteria, which photosynthesize in a plantlike way Figure 16.13C, D Colorized SEM 2,800  LM 650  Photosynthetic cells Nitrogen-fixing cells Colorized SEM 2,8000 

36. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings CONNECTION 16.14 Some bacteria cause disease Pathogenic bacteria cause disease by producing –Exotoxins or endotoxins SEM 12,000  Spirochete that causes Lyme disease “Bull’s-eye”rash Tick that carries the Lyme disease bacterium SEM 2,800  Figure 16.14A, B

37. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Figure 16.15 CONNECTION 16.15 Bacteria can be used as biological weapons Bacteria, such as the species that causes anthrax –Can be used as biological weapons

38. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings CONNECTION 16.16 Prokaryotes help recycle chemicals and clean up the environment Bioremediation –Is the use of organisms to clean up pollution

39. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Prokaryotes are decomposers in –Sewage treatment and can clean up oil spills and toxic mine wastes Figure 16.16A, B Liquid wastes Outflow Rotating spray arm Rock bed coated with aerobic bacteria and fungi

40. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings PROTISTS 16.17 The eukaryotic cell probably originated as a community of prokaryotes Eukaryotic cells –Evolved from prokaryotic cells more than 2 billion years ago

41. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings The nucleus and endomembrane system –Probably evolved from infoldings of the plasma membrane

42. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Mitochondria and chloroplasts –Probably evolved from aerobic and photosynthetic endosymbionts, respectively

43. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings A model of the origin of eukaryotes Cytoplasm Ancestral prokaryote Plasma membrane Endoplasmic reticulum Nucleus Nuclear envelope Cell with nucleus and endomembrane system Membrane infolding Aerobic heterotrophic prokaryote Ancestral host cell Endosymbiosis Mitochondrion Chloroplast Photosynthetic eukaryotic cell Photosynthetic prokaryote Mitochondrion Some cells Figure 16.17

44. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.18 Protists are an extremely diverse assortment of eukaryotes Protists –Are mostly unicellular eukaryotes Molecular systematics –Is exploring eukaryotic phylogeny LM 275  Figure 16.18

45. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.19 A tentative phylogeny of eukaryotes includes multiple clades of protists The taxonomy of protists –Is a work in progress Diplomonads Euglenozoans Dinoflagellates Apicomplexans Ciliates Water molds Diatoms Brown algae Amoebas Plasmodial slime molds Cellular slime molds Fungi Choanoflagellates Animals Red algae Green algae Closest algal relatives of plants Plants AlveolatesStramenopila Amoebozoa Ancestral eukaryote Figure 16.19

46. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.20 Diplomonads and euglenozoans include some flagellated parasites The parasitic Giardia –Is a diplomonad with highly reduced mitochondria Colorized SEM 4,000  Figure 16.20A

47. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Euglenozoans –Include trypanosomes and Euglena Colorized SEM 1,300  Figure 16.20B, C

48. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.21 Alveolates have sacs beneath the plasma membrane and include dinoflagellates, apicomplexans, and ciliates Dinoflagellates –Are unicellular algae SEM 2,300  Figure 16.21A

49. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Apicomplexans are parasites –Such as Plasmodium, which causes malaria Red blood cell Apex TEM 26,000  Figure 16.21B

50. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Cilliates –Use cilia to move and feed Cilia Macronucleus LM 60  Figure 16.21C

51. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.22 Stramenopiles are named for their “hairy” flagella and include the water molds, diatoms, and brown algae This clade includes –Fungus-like water molds Figure 16.22A

52. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings –Photosynthetic, unicellular diatoms LM 400  Figure 16.22B

53. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings –Brown algae, large complex seaweeds Figure 16.22C

54. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.23 Amoebozoans have pseudopodia and include amoebas and slime molds Amoebas –Move and feed by means of pseudopodia LM 185  Figure 16.23A

55. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings A plasmodial slime mold is a multinucleate plasmodium –That forms reproductive structures under adverse conditions Figure 16.23B

56. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Cellular slime molds –Have unicellular and multicellular stages Slug-like aggregate 45  LM 1,000  15  Amoeboid cells Reproductive structure Figure 16.23C

57. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.24 Red algae and green algae are the closest relatives of land plants Red algae –Contribute to coral reefs Figure 16.24A

58. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Green algae –May be unicellular, colonial, or multicellular Chlamydomonas Volvox colonies LM 80  LM 1,200  Figure 16.24B

59. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings The life cycles of many algae –Involve the alternation of haploid gametophyte and diploid sporophyte generations Mitosis Male gametophyte Gametes Spores Mitosis Meiosis Fusion of gametes Female gametophyte Zygote Sporophyte Mitosis Haploid (n) Diploid (2n) Key Figure 16.24C

60. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 16.25 Multicellularity evolved several times in eukaryotes Multicellularity evolved in several different lineages –Probably by specialization of the cells of colonial protists Figure 16.25 Unicellular protist ColonyEarly multicellular organism with specialized, interdepen- dent cells Later organism that produces gametes Food- synthesizing cells Locomotor cells Somatic cells Gamete 1 2 3

61. Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Multicellular life arose over a billion years ago