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© 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor,

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1 © 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor, Simon, and Dickey Chapter 16 Microbial Life: Prokaryotes and Protists

2 Figure 16.0_1

3 Figure 16.0_2 Chapter 16: Big Ideas ProkaryotesProtists

4 Figure 16.0_3

5 PROKARYOTES © 2012 Pearson Education, Inc.

6  Prokaryotic cells are smaller than eukaryotic cells. –Prokaryotes range from 1–5 µm in diameter. –Eukaryotes range from 10–100 µm in diameter.  The collective biomass of prokaryotes is at least 10 times that of all eukaryotes Prokaryotes are diverse and widespread © 2012 Pearson Education, Inc.

7 Figure 16.1

8  Prokaryotes live in habitats –too cold, –too hot, –too salty, –too acidic, and –too alkaline for eukaryotes to survive.  Some bacteria are pathogens, causing disease. But most bacteria on our bodies are benign or beneficial Prokaryotes are diverse and widespread © 2012 Pearson Education, Inc.

9  Several hundred species of bacteria live in and on our bodies, –decomposing dead skin cells, –supplying essential vitamins, and –guarding against pathogenic organisms.  Prokaryotes in soil decompose dead organisms, sustaining chemical cycles Prokaryotes are diverse and widespread © 2012 Pearson Education, Inc.

10  Prokaryotic cells have three common cell shapes. –Cocci are spherical prokaryotic cells. They sometimes occur in chains that are called streptococci. –Bacilli are rod-shaped prokaryotes. Bacilli may also be threadlike, or filamentous. –Spiral prokaryotes are like a corkscrew. –Short and rigid prokaryotes are called spirilla. –Longer, more flexible cells are called spirochetes External features contribute to the success of prokaryotes © 2012 Pearson Education, Inc.

11 Figure 16.2A Cocci Bacilli Spirochete

12 Figure 16.2A_1 Cocci

13 Figure 16.2A_2 Bacilli

14 Figure 16.2A_3 Spirochete

15  Nearly all prokaryotes have a cell wall. Cell walls –provide physical protection and –prevent the cell from bursting in a hypotonic environment.  When stained with Gram stain, cell walls of bacteria are either –Gram-positive, with simpler cell walls containing peptidoglycan, or –Gram-negative, with less peptidoglycan, and more complex and more likely to cause disease External features contribute to the success of prokaryotes © 2012 Pearson Education, Inc.

16 Figure 16.2B

17  The cell wall of many prokaryotes is covered by a capsule, a sticky layer of polysaccharides or protein.  The capsule –enables prokaryotes to adhere to their substrate or to other individuals in a colony and –shields pathogenic prokaryotes from attacks by a host’s immune system External features contribute to the success of prokaryotes © 2012 Pearson Education, Inc.

18 Figure 16.2C Capsule Tonsil cell Bacterium

19  Some prokaryotes have external structures that extend beyond the cell wall. –Flagella help prokaryotes move in their environment. –Hairlike projections called fimbriae enable prokaryotes to stick to their substrate or each other External features contribute to the success of prokaryotes © 2012 Pearson Education, Inc.

20 Figure 16.2D Flagella Fimbriae

21  Prokaryote population growth –occurs by binary fission, –can rapidly produce a new generation within hours, and –can generate a great deal of genetic variation –by spontaneous mutations, –increasing the likelihood that some members of the population will survive changes in the environment Populations of prokaryotes can adapt rapidly to changes in the environment © 2012 Pearson Education, Inc.

22  The genome of a prokaryote typically –has about one-thousandth as much DNA as a eukaryotic genome and –is one long, circular chromosome packed into a distinct region of the cell.  Many prokaryotes also have additional small, circular DNA molecules called plasmids, which replicate independently of the chromosome Populations of prokaryotes can adapt rapidly to changes in the environment © 2012 Pearson Education, Inc.

23 Figure 16.3A ChromosomePlasmids

24  Some prokaryotes form specialized cells called endospores that remain dormant through harsh conditions.  Endospores can survive extreme heat or cold Populations of prokaryotes can adapt rapidly to changes in the environment © 2012 Pearson Education, Inc.

25 Figure 16.3B Endospore

26  Prokaryotes exhibit much more nutritional diversity than eukaryotes.  Two sources of energy are used. –Phototrophs capture energy from sunlight. –Chemotrophs harness the energy stored in chemicals Prokaryotes have unparalleled nutritional diversity © 2012 Pearson Education, Inc.

27  Two sources of carbon are used by prokaryotes. –Autotrophs obtain carbon atoms from carbon dioxide. –Heterotrophs obtain their carbon atoms from the organic compounds present in other organisms Prokaryotes have unparalleled nutritional diversity © 2012 Pearson Education, Inc.

28  The terms that describe how prokaryotes obtain energy and carbon are combined to describe their modes of nutrition. –Photoautotrophs obtain energy from sunlight and use carbon dioxide for carbon. –Photoheterotrophs obtain energy from sunlight but get their carbon atoms from organic molecules. –Chemoautotrophs harvest energy from inorganic chemicals and use carbon dioxide for carbon. –Chemoheterotrophs acquire energy and carbon from organic molecules Prokaryotes have unparalleled nutritional diversity © 2012 Pearson Education, Inc.

29 Figure 16.4 ENERGY SOURCE Sunlight Photoautotrophs Oscilliatoria Photoheterotrophs RhodopseudomonasA Bdellovibrio attacking a larger cell Chemicals Chemoautotrophs Unidentified “rock-eating” bacteria Chemoheterotrophs CARBON SOURCE Organic compounds CO 2

30 Figure 16.4_1 Photoautotrophs Oscilliatoria

31 Figure 16.4_2 Photoheterotrophs Rhodopseudomonas

32 Figure 16.4_3 Chemoautotrophs Unidentified “rock-eating” bacteria

33 Figure 16.4_4 A Bdellovibrio attacking a larger cell Chemoheterotrophs

34  Biofilms –are complex associations of one or several species of prokaryotes and –may also include protists and fungi.  Prokaryotes attach to surfaces and form biofilm communities that –are difficult to eradicate and –may cause medical and environmental problems CONNECTION: Biofilms are complex associations of microbes © 2012 Pearson Education, Inc.

35  Biofilms are large and complex “cities” of microbes that –communicate by chemical signals, –coordinate a division of labor and defense against invaders, and –use channels to distribute nutrients and collect wastes CONNECTION: Biofilms are complex associations of microbes © 2012 Pearson Education, Inc.

36  Biofilms that form in the environment can be difficult to eradicate.  Biofilms –clog and corrode pipes, –gum up filters and drains, and –Coat the hulls of ships CONNECTION: Biofilms are complex associations of microbes © 2012 Pearson Education, Inc.

37 Figure 16.5

38  Prokaryotes are useful for cleaning up contaminants in the environment because prokaryotes –have great nutritional diversity, –are quickly adaptable, and –can form biofilms CONNECTION: Prokaryotes help clean up the environment © 2012 Pearson Education, Inc.

39  Bioremediation is the use of organisms to remove pollutants from –soil, –air, or –water CONNECTION: Prokaryotes help clean up the environment © 2012 Pearson Education, Inc.

40  Prokaryotic decomposers are the mainstays of sewage treatment facilities. –Raw sewage is first passed through a series of screens and shredders. –Solid matter then settles out from the liquid waste, forming sludge. –Sludge is gradually added to a culture of anaerobic prokaryotes, including bacteria and archaea. –The microbes decompose the organic matter into material that can be placed in a landfill or used as fertilizer CONNECTION: Prokaryotes help clean up the environment © 2012 Pearson Education, Inc.

41  Liquid wastes are treated separately from the sludge. –Liquid wastes are sprayed onto a thick bed of rocks. –Biofilms of aerobic bacteria and fungi growing on the rocks remove much of the dissolved organic material. –Fluid draining from the rocks is sterilized and then released, usually into a river or ocean CONNECTION: Prokaryotes help clean up the environment © 2012 Pearson Education, Inc.

42 Figure 16.6A Rotating spray arm Rock bed coated with aerobic prokaryotes and fungi Outflow Liquid wastes

43 Figure 16.6A_1 Rotating spray arm Rock bed coated with aerobic prokaryotes and fungi Outflow Liquid wastes

44 Figure 16.6A_2 Rotating spray arm Rock bed coated with aerobic prokaryotes and fungi

45  Bioremediation is becoming an important tool for cleaning up toxic chemicals released into the soil and water by industrial processes.  Environmental engineers change the natural environment to accelerate the activity of naturally occurring prokaryotes capable of metabolizing pollutants CONNECTION: Prokaryotes help clean up the environment © 2012 Pearson Education, Inc.

46 Figure 16.6B

47  New studies of representative genomes of prokaryotes and eukaryotes strongly support the three-domain view of life. –Prokaryotes are now classified into two domains: –Bacteria and –Archaea. –Archaea have at least as much in common with eukaryotes as they do with bacteria Bacteria and archaea are the two main branches of prokaryotic evolution © 2012 Pearson Education, Inc.

48 Table 16.7

49  Archaeal inhabitants of extreme environments have unusual proteins and other molecular adaptations that enable them to metabolize and reproduce effectively. –Extreme halophiles thrive in very salty places. –Extreme thermophiles thrive in –very hot water, such as geysers, and –acid pools Archaea thrive in extreme environments— and in other habitats © 2012 Pearson Education, Inc.

50 Figure 16.8A

51  Methanogens –live in anaerobic environments, –give off methane as a waste product from –the digestive tracts of cattle and deer and –decomposing materials in landfills Archaea thrive in extreme environments— and in other habitats © 2012 Pearson Education, Inc.

52 Figure 16.8B

53  The domain Bacteria is currently divided into five groups, based on comparisons of genetic sequences.  1. Proteobacteria –are all gram negative, –share a particular rRNA sequence, and –represent all four modes of nutrition Bacteria include a diverse assemblage of prokaryotes © 2012 Pearson Education, Inc.

54 –Thiomargarita namibiensis is a type of proteobacteria that –is a giant among prokaryotes, typically ranging up to 100–300 microns in diameter, –uses H 2 S to generate organic molecules from CO 2, and –produces sulfur wastes, seen as small greenish globules in the following figure Bacteria include a diverse assemblage of prokaryotes © 2012 Pearson Education, Inc.

55 Figure 16.9A

56 –Proteobacteria also include Rhizobium species that –live symbiotically in root nodules of legumes and –convert atmospheric nitrogen gas into a form usable by their legume host. –Symbiosis is a close association between organisms of two or more species. –Rhizobium is an endosymbiont, living within another species Bacteria include a diverse assemblage of prokaryotes © 2012 Pearson Education, Inc.

57 Figure 32.13B Shoot Nodules Roots Bacteria within vesicle in an infected cell

58  2. Gram-positive bacteria –rival proteobacteria in diversity and –include the actinomycetes common in soil. –Streptomyces is often cultured by pharmaceutical companies as a source of many antibiotics Bacteria include a diverse assemblage of prokaryotes © 2012 Pearson Education, Inc.

59 Figure 16.9B

60  3. Cyanobacteria –Cyanobacteria are the only group of prokaryotes with plantlike, oxygen-generating photosynthesis. –Some species, such as Anabaena, have specialized cells that fix nitrogen Bacteria include a diverse assemblage of prokaryotes © 2012 Pearson Education, Inc.

61 Figure 16.9C Photosynthetic cells Nitrogen-fixing cells

62  4. Chlamydias –Chlamydias live inside eukaryotic host cells. –Chlamydia trachomatis –is a common cause of blindness in developing countries and –is the most common sexually transmitted disease in the United States Bacteria include a diverse assemblage of prokaryotes © 2012 Pearson Education, Inc.

63 Figure 16.9D

64  5. Spirochetes are –helical bacteria and –notorious pathogens, causing –syphilis and –Lyme disease Bacteria include a diverse assemblage of prokaryotes © 2012 Pearson Education, Inc.

65 Figure 16.9E

66  All organisms are almost constantly exposed to pathogenic bacteria.  Most bacteria that cause illness do so by producing a poison. –Exotoxins are proteins that bacterial cells secrete into their environment. –Endotoxins are components of the outer membrane of gram-negative bacteria CONNECTION: Some bacteria cause disease © 2012 Pearson Education, Inc.

67 Figure 16.10

68  Koch’s postulates are four essential conditions used to establish that a certain bacterium is the cause of a disease. They are 1. find the bacterium in every case of the disease, 2. isolate the bacterium from a person who has the disease and grow it in pure culture, 3. show that the cultured bacterium causes the disease when transferred to a healthy subject, and 4. isolate the bacterium from the experimentally infected subject SCIENTIFIC DISCOVERY: Koch’s postulates are used to prove that a bacterium causes a disease © 2012 Pearson Education, Inc.

69  Koch’s postulates were used to demonstrate that the bacterium Helicobacter pylori is the cause of most peptic ulcers.  The 2005 Nobel Prize in Medicine was awarded to Barry Marshall and Robin Warren for this discovery SCIENTIFIC DISCOVERY: Koch’s postulates are used to prove that a bacterium causes a disease © 2012 Pearson Education, Inc.

70 Figure 16.11

71  Bacteria that cause anthrax and the plague can be used as biological weapons. –Bacillus anthracis killed five people in the United States in –Yersinia pestis bacteria –are typically carried by rodents and transmitted by fleas, causing the plague and –can cause a pneumonic form of plague if inhaled CONNECTION: Bacteria can be used as biological weapons © 2012 Pearson Education, Inc.

72 Figure 16.12

73  Clostridium botulinum produces the exotoxin botulinum, the deadliest poison on earth.  Botulinum blocks transmission of nerve signals and prevents muscle contraction CONNECTION: Bacteria can be used as biological weapons © 2012 Pearson Education, Inc.

74 PROTISTS © 2012 Pearson Education, Inc.

75  Protists –are a diverse collection of mostly unicellular eukaryotes, –may constitute multiple kingdoms within the Eukarya, and –refer to eukaryotes that are not –plants, –animals, or –fungi Protists are an extremely diverse assortment of eukaryotes © 2012 Pearson Education, Inc.

76  Protists obtain their nutrition in many ways. Protists include –autotrophs, called algae, producing their food by photosynthesis, –heterotrophs, called protozoans, eating bacteria and other protists, –heterotrophs, called parasites, deriving their nutrition from a living host, and –mixotrophs, using photosynthesis and heterotrophy Protists are an extremely diverse assortment of eukaryotes © 2012 Pearson Education, Inc.

77 Figure 16.13A AutotrophyHeterotrophy Caulerpa, a green alga Giardia, a parasite Mixotrophy Euglena

78 Figure 16.13A_1 Autotrophy Caulerpa, a green alga

79 Figure 16.13A_2 Heterotrophy Giardia, a parasite

80 Figure 16.13A_3 Mixotrophy Euglena

81  Protists are found in many habitats including –anywhere there is moisture and –the bodies of host organisms Protists are an extremely diverse assortment of eukaryotes © 2012 Pearson Education, Inc.

82 Figure 16.13B

83 Figure 16.13B_1

84 Figure 16.13B_2

85  Recent molecular and cellular studies indicate that nutritional modes used to categorize protists do not reflect natural clades.  Protist phylogeny remains unclear.  One hypothesis, used here, proposes five monophyletic supergroups Protists are an extremely diverse assortment of eukaryotes © 2012 Pearson Education, Inc.

86  The endosymbiont theory explains the origin of mitochondria and chloroplasts. –Eukaryotic cells evolved when prokaryotes established residence within other, larger prokaryotes. –This theory is supported by present-day mitochondria and chloroplasts that –have structural and molecular similarities to prokaryotic cells and –replicate and use their own DNA, separate from the nuclear DNA of the cell EVOLUTION CONNECTION: Secondary endosymbiosis is the key to much of protist diversity © 2012 Pearson Education, Inc.

87 Figure 16.14_s1 Primary endosymbiosis Cyanobacterium Evolved into chloroplast Nucleus Heterotrophic eukaryote 2 1

88 Figure 16.14_s2 Primary endosymbiosis Green alga Chloroplast Cyanobacterium Evolved into chloroplast Nucleus Heterotrophic eukaryote Chloroplast Red alga Autotrophic eukaryotes 3 2 1

89 Figure 16.14_s3 Primary endosymbiosis Green alga Chloroplast Cyanobacterium Evolved into chloroplast Nucleus Heterotrophic eukaryote Chloroplast Red alga Autotrophic eukaryotes Heterotrophic eukaryotes

90  Secondary endosymbiosis is –the process in which an autotrophic eukaryotic protist became endosymbiotic in a heterotrophic eukaryotic protist and –key to protist diversity EVOLUTION CONNECTION: Secondary endosymbiosis is the key to much of protist diversity © 2012 Pearson Education, Inc.

91 Figure 16.14_s4 Primary endosymbiosis Green alga Chloroplast Cyanobacterium Evolved into chloroplast Nucleus Heterotrophic eukaryote Chloroplast Red alga Autotrophic eukaryotes Heterotrophic eukaryotes Secondary endosymbiosis

92 Figure 16.14_s5 Primary endosymbiosis Green alga Chloroplast Cyanobacterium Evolved into chloroplast Nucleus Heterotrophic eukaryote Chloroplast Red alga Autotrophic eukaryotes Heterotrophic eukaryotes Euglena Remnant of green alga Secondary endosymbiosis

93  Chromalveolates include –diatoms, unicellular algae with a glass cell wall containing silica, Chromalveolates represent the range of protist diversity © 2012 Pearson Education, Inc.

94 Figure 16.15A

95  Chromalveolates include –diatoms, unicellular algae with a glass cell wall containing silica, –dinoflagellates, unicellular autotrophs, heterotrophs, and mixotrophs that are common components of marine plankton, Chromalveolates represent the range of protist diversity © 2012 Pearson Education, Inc.

96 Figure 16.15B

97  Chromalveolates include –diatoms, unicellular algae with a glass cell wall containing silica, –dinoflagellates, unicellular autotrophs, heterotrophs, and mixotrophs that are common components of marine plankton, –brown algae, large, multicellular autotrophs, Chromalveolates represent the range of protist diversity © 2012 Pearson Education, Inc.

98 Figure 16.15C

99  Chromalveolates include –diatoms, unicellular algae with a glass cell wall containing silica, –dinoflagellates, unicellular autotrophs, heterotrophs, and mixotrophs that are common components of marine plankton, –brown algae, large, multicellular autotrophs, –water molds, unicellular heterotrophs, Chromalveolates represent the range of protist diversity © 2012 Pearson Education, Inc.

100 Figure 16.15D

101  Chromalveolates include –diatoms, unicellular algae with a glass cell wall containing silica, –dinoflagellates, unicellular autotrophs, heterotrophs, and mixotrophs that are common components of marine plankton, –brown algae, large, multicellular autotrophs, –water molds, unicellular heterotrophs, –ciliates, unicellular heterotrophs and mixotrophs that use cilia to move and feed, Chromalveolates represent the range of protist diversity © 2012 Pearson Education, Inc.

102 Figure 16.15E Mouth

103  Chromalveolates include –diatoms, unicellular algae with a glass cell wall containing silica, –dinoflagellates, unicellular autotrophs, heterotrophs, and mixotrophs that are common components of marine plankton, –brown algae, large, multicellular autotrophs, –water molds, unicellular heterotrophs, –ciliates, unicellular heterotrophs and mixotrophs that use cilia to move and feed, and –a group including parasites, such as Plasmodium, which causes malaria Chromalveolates represent the range of protist diversity © 2012 Pearson Education, Inc.

104  Fossil fuels –are the organic remains of organisms that lived hundreds of millions of years ago and –primarily consist of –diatoms and –primitive plants CONNECTION: Can algae provide a renewable source of energy? © 2012 Pearson Education, Inc.

105  Lipid droplets in diatoms and other algae may serve as a renewable source of energy.  If unicellular algae could be grown on a large scale, this oil could be harvested and processed into biodiesel.  Numerous technical hurdles remain before industrial-scale production of biofuel from algae becomes a reality CONNECTION: Can algae provide a renewable source of energy? © 2012 Pearson Education, Inc.

106 Figure 16.16

107  The two largest groups of Rhizaria are among the organisms referred to as amoebas.  Amoebas move and feed by means of pseudopodia, temporary extensions of the cell Rhizarians include a variety of amoebas © 2012 Pearson Education, Inc.

108  Foraminiferans –are found in the oceans and in fresh water, –have porous shells, called tests, composed of calcium carbonate, and –have pseudopodia that function in feeding and locomotion Rhizarians include a variety of amoebas © 2012 Pearson Education, Inc.

109 Figure 16.17A

110 Figure 16.17A_1

111 Figure 16.17A_2

112  Radiolarians –are mostly marine and –produce a mineralized internal skeleton made of silica Rhizarians include a variety of amoebas © 2012 Pearson Education, Inc.

113 Figure 16.17B

114  Excavata has recently been proposed as a clade on the basis of molecular and morphological similarities.  The name refers to an “excavated” feeding groove possessed by some members of the group.  Excavates –have modified mitochondria that lack functional electron transport chains and –use anaerobic pathways such as glycolysis to extract energy Some excavates have modified mitochondria © 2012 Pearson Education, Inc.

115  Excavates include –heterotrophic termite endosymbionts Some excavates have modified mitochondria © 2012 Pearson Education, Inc.

116 Figure 16.13B

117  Excavates include –heterotrophic termite endosymbionts, –autotrophic species, –mixotrophs such as Euglena Some excavates have modified mitochondria © 2012 Pearson Education, Inc.

118 Figure 16.13A_3 Mixotrophy Euglena

119  Excavates include –heterotrophic termite endosymbionts, –autotrophic species, –mixotrophs such as Euglena, –the common waterborne parasite Giardia intestinalis, Some excavates have modified mitochondria © 2012 Pearson Education, Inc.

120 Figure 16.13A AutotrophyHeterotrophy Caulerpa, a green alga Giardia, a parasite Mixotrophy Euglena

121  Excavates include –heterotrophic termite endosymbionts, –autotrophic species, –mixotrophs such as Euglena, –the common waterborne parasite Giardia intestinalis, –the parasite Trichomonas vaginalis, which causes 5 million new infections each year of human reproductive tracts, Some excavates have modified mitochondria © 2012 Pearson Education, Inc.

122 Figure 16.18A Flagella Undulating membrane

123  Excavates include –heterotrophic termite endosymbionts, –autotrophic species, –mixotrophs such as Euglena, –the common waterborne parasite Giardia intestinalis, –the parasite Trichomonas vaginalis, which causes 5 million new infections each year of human reproductive tracts, and –the parasite Trypanosoma, which causes sleeping sickness in humans Some excavates have modified mitochondria © 2012 Pearson Education, Inc.

124 Figure 16.18B

125  Unikonta is a controversial grouping joining –amoebozoans and –a group that includes animals and fungi, addressed at the end of this unit on protists Unikonts include protists that are closely related to fungi and animals © 2012 Pearson Education, Inc.

126  Amoebozoans have lobe-shaped pseudopodia and include –many species of free-living amoebas, –some parasitic amoebas, and –slime molds Unikonts include protists that are closely related to fungi and animals © 2012 Pearson Education, Inc.

127 Figure 16.19A

128  Plasmodial slime molds –are common where there is moist, decaying organic matter and –consist of a single, multinucleate mass of cytoplasm undivided by plasma membranes, called a plasmodium Unikonts include protists that are closely related to fungi and animals © 2012 Pearson Education, Inc.

129 Figure 16.19B

130 Figure 16.19B_1

131 Figure 16.19B_2

132  Cellular slime molds –are common on rotting logs and decaying organic matter and –usually exist as solitary amoeboid cells, but when food is scarce, amoeboid cells –swarm together, forming a slug-like aggregate that wanders around for a short time and then –forms a stock supporting an asexual reproductive structure that produces spores Unikonts include protists that are closely related to fungi and animals © 2012 Pearson Education, Inc.

133 Figure 16.19C

134  Archaeplastids include: –red algae, –green algae, and –land plants Archaeplastids include red algae, green algae, and land plants © 2012 Pearson Education, Inc.

135  Red algae –are mostly multicellular, –contribute to the structure of coral reefs, and –are commercially valuable Archaeplastids include red algae, green algae, and land plants © 2012 Pearson Education, Inc.

136 Figure 16.20A

137  Green algae may be unicellular, colonial, or multicellular. –Volvox is a colonial green algae, and –Chlamydomonas is a unicellular alga propelled by two flagella Archaeplastids include red algae, green algae, and land plants © 2012 Pearson Education, Inc.

138 Figure 16.20B VolvoxChlamydomonas

139 Figure 16.20B_1 Volvox

140 Figure 16.20B_2 Chlamydomonas

141  Ulva, or sea lettuce, is –a multicellular green alga with –a complex life cycle that includes an alternation of generations that consists of –a multicellular diploid (2n) form, the sporophyte, that alternates with –a multicellular haploid (1n) form, the gametophyte Archaeplastids include red algae, green algae, and land plants © 2012 Pearson Education, Inc.

142 Figure 16.20C_s1 Mitosis Spores Mitosis Female gametophyte Gametes Male gametophyte Key Haploid (n) Diploid (2n)

143 Figure 16.20C_s2 Mitosis Spores Mitosis Female gametophyte Gametes Male gametophyte Fusion of gametes Zygote Key Haploid (n) Diploid (2n)

144 Figure 16.20C_s3 Mitosis Spores Meiosis Mitosis Female gametophyte Gametes Male gametophyte Fusion of gametes Zygote Sporophyte Mitosis Key Haploid (n) Diploid (2n)

145 Figure 16.20C_2

146  The origin of the eukaryotic cell led to an evolutionary radiation of new forms of life.  Unicellular protists are much more diverse in form than simpler prokaryotes EVOLUTION CONNECTION: Multicellularity evolved several times in eukaryotes © 2012 Pearson Education, Inc.

147  Multicellular organisms (seaweeds, plants, animals, and most fungi) are fundamentally different from unicellular organisms. –A multicellular organism has various specialized cells that perform different functions and are interdependent. –All of life’s activities occur within a single cell in unicellular organisms EVOLUTION CONNECTION: Multicellularity evolved several times in eukaryotes © 2012 Pearson Education, Inc.

148  Multicellular organisms have evolved from three different lineages: –brown algae evolved from chromalveolates, –fungi and animals evolved from unikonts, and –red algae and green algae evolved from achaeplastids EVOLUTION CONNECTION: Multicellularity evolved several times in eukaryotes © 2012 Pearson Education, Inc.

149 Figure 16.21A Key Animals Choanoflagellates Fungi Nucleariids Land plants Amoebozoans Charophytes Other green algae Red algae Green algae Archaeplastids Unikonts Ancestral eukaryote All unicellular Both unicellular and multicellular All multicellular

150  One hypothesis states that two separate unikont lineages led to fungi and animals, diverging more than 1 billion years ago.  A combination of morphological and molecular evidence suggests that choanoflagellates are the closest living protist relative of animals EVOLUTION CONNECTION: Multicellularity evolved several times in eukaryotes © 2012 Pearson Education, Inc.

151 Figure 16.21B Nucleariids Fungi 1 billion years ago Choanoflagellates A nucleariid, closest living protistan relative of fungi Individual choanoflagellate Colonial choanoflagellate Animals Sponge collar cell

152 Figure 16.21B_1 Nucleariids Fungi A nucleariid, closest living protistan relative of fungi

153 Figure 16.21B_2 Choanoflagellates Individual choanoflagellate Colonial choanoflagellate Animals Sponge collar cell

154 Figure 16.21B_3

155 1.Describe the structures and functions of the diverse features of prokaryotes; explain how these features have contributed to their success. 2.Explain how populations of prokaryotes can adapt rapidly to changes in their environment. 3.Describe the nutritional diversity of prokaryotes and explain the significance of biofilms. 4.Explain how prokaryotes help clean up the environment. 5.Compare the characteristics of the three domains of life; explain why biologists consider Archaea to be more closely related to Eukarya than to Bacteria. You should now be able to © 2012 Pearson Education, Inc.

156 6.Describe the diverse types of Archaea living in extreme and moderate environments. 7.Distinguish between the subgroups of the domain Bacteria, noting the particular structure, special features, and habitats of each group. 8.Distinguish between bacterial exotoxins and endotoxins, noting examples of each. 9.Describe the steps of Koch’s postulates and explain why they are used. 10.Explain how bacteria can be used as biological weapons. You should now be able to © 2012 Pearson Education, Inc.

157 11.Describe the extremely diverse assortment of eukaryotes. 12.Explain how primary endosymbiosis and secondary endosymbiosis led to further cellular diversity. 13.Describe the major protist clades noting characteristics and examples of each. 14.Describe the life cycle of Ulva, noting each form in the alternation of generations and how each is produced. 15.Explain how multicellular life may have evolved in eukaryotes. You should now be able to © 2012 Pearson Education, Inc.

158 Figure 16.UN01 Nutritional modeEnergy sourceCarbon source PhotoautotrophSunlight Chemoautotroph Photoheterotroph Chemoheterotroph Inorganic chemicals Sunlight Organic compounds CO 2

159 Figure 16.UN02 Exotoxin Secreted by cell Staphylococcus aureusSalmonella enteritidis Endotoxin Component of gram- negative plasma membrane

160 Figure 16.UN02_1 Exotoxin Secreted by cell Staphylococcus aureus

161 Figure 16.UN02_2 Salmonella enteritidis Endotoxin Component of gram- negative plasma membrane

162 Figure 16.UN03 Red algae Other green algae (b) Land plants Amoebozoans Nucleariids (d) (e) (f) Green algae Ancestral eukaryote (a) (c)


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