1. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. CHAPTER 5 Protozoan Groups Unicellular Eukaryotes 11-1

2. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Emergence of Eukaryotes Protozoa Lack a cell wall Have at least one motile stage in life cycle Most ingest their food 11-2

3. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Form and Function Locomotion Cilia and flagella Contain 9 pairs of microtubules arranged around a central pair Cilia Propel water parallel to the cell surface Flagella Propel water parallel to the flagellum axis 11-3

4. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-4

5. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-5

6. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-6

7. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Form and Function How Pseudopodia Work Endoplasm Contains nucleus and cytoplasmic organelles Ectoplasm More transparent (hyaline) Contains bases of cilia or flagella Often more rigid Appears granular 11-7

8. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-8

9. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Form and Function Functional Components of Protozoan Cells Nucleus –Membrane bound organelle –Contains DNA in the form of chromosomes –Chromatin often clumps irregularly leaving clear areas –Nucleoli are often present –Macronuclei of ciliates Compact or condensed with no clear areas 11-9

10. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Form and Function Mitochondria –Involved in energy production Golgi apparatus Part of the secretory system of the endoplasmic reticulum Plastids Organelles containing a variety of photosynthetic pigments Perhaps added when a cyanobacterium was engulfed but not digested Chloroplasts contain different types of chlorophylls 11-10

11. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-11

12. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Form and Function Extrusomes General term applied to membrane-bound organelles used to extrude material from cell All not believed to be homologous Ciliate trichocysts are examples 11-12

13. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Form and Function Nutrition Holozoic nutrition implies phagocytosis Infolding of cell membrane surrounds food particle Invagination pinches off Food particle contained in intracellular vesicle Food vacuole (phagosome) Lysosomes fuse with phagosome and release enzymes 11-13

14. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Form and Function Digested products absorbed across vacuole membrane Undigestible material released to outside by exocytosis In ciliates, site of phagocytosis called a cytostome Many have a point for expulsion of wastes Cytopyge or cytoproct 11-14

15. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-15

16. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Form and Function Excretion and Osmoregulation Excretion of metabolic wastes is by diffusion Primary end product of nitrogen metabolism Ammonia Contractile vacuoles fill and empty to maintain osmotic balance No known lipid bilayer that retains water against a gradient A proton pump may actively transport H + ions and cotransport bicarbonate into vacuole Water enters by osmosis 11-16

17. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Form and Function Reproduction Asexual Processes Fission Produces more individuals than other forms of reproduction Binary fission is most common Two identical individuals produced Budding Occurs when a small progeny cell (bud) pinches off from parent cell Bud grows to adult size 11-17

18. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-18

19. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Form and Function Multiple fission (schizogony) Cytokinesis preceded by several nuclear divisions May individuals formed simultaneously If union of gametes precedes multiple fission Called sporogony 11-19

20. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Form and Function Sexual Processes All protozoa reproduce asexually Some exclusively Sexual reproduction also occurs widely among protozoa Meiosis May occur during or just before gamete formation In other groups, meiosis occurs after fertilization (zygotic meiosis) All individuals produced asexually in life cycle up to next zygote are haploid 11-20

21. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Form and Function Encystment and Excystment Unicellular forms amazingly successful in extremely harsh conditions Related to the ability to form cysts Dormant forms that shut down metabolism and have a resistant external covering (secreted by Golgi apparatus) Encystment is not found in Paramecium, rare or absent in marine forms Excystment Escape from cysts when environmental conditions are favorable 11-21

22. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Major Protozoan Taxa Clade Viridiplantae Unicellular and multicellular green algae, bryophytes, and vascular plants Phylum Chlorophyta Flagellated, autotrophic, single-celled algae such as Chlamydomonas, as well as colonial forms like Gonium and Volvox 11-22

23. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-23

24. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Major Protozoan Taxa Phylum Euglenozoa Have a series of longitudinal microtubules Stiffen the cell membrane into a pellicle Subphylum Euglenida Chloroplasts surrounded by a double membrane 11-24

25. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-25

26. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Major Protozoan Taxa Subphylum Kinetoplasta Zooflagellates –Holozoic or saprozoic nutrition –Most are symbiotic –Trypanosoma Important genus of protozoan parasites –Some not pathogenic –T. brucei gambiense and T. b. rhodesiense »Cause African sleeping sickness in humans –T. cruzi »Causes Chagas disease »All transmitted by tsetse flies »Transmitted by “kissing bugs” 11-26

27. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Major Protozoan Taxa Clade Alveolata Three traditional phyla united by the shared presence of alveoli Membrane-bound sacs beneath cell membrane Function varies with phylum Phylum Ciliophora Phylum Dinoflagellata Phylum Apicomplexa 11-27

28. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Major Protozoan Taxa Phylum Ciliophora Ciliates are the most diverse and specialized protozoans Larger than most other protozoa Most free-living, some commensal and parasitic Usually solitaire and motile Most free-living in freshwater or marine habitats 11-28

29. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-29

30. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Major Protozoan Taxa Multinucleate Macronuclei Metabolic and developmental functions Divides amitotically Micronuclei Involved in sexual reproduction and give rise to macronuclei afterwards Divide mitotically Trichocysts and toxicysts in some Expel long thread-like structures when stimulated Believed to be defensive mechanism 11-30

31. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-31

32. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Major Protozoan Taxa Paramecium may be studied as a typical free-living ciliate Slipper-shaped Asymmetrical appearance caused by oral groove Pellicle may be ornamented, have ridges, or papillalike projections Trichocysts present Cytostome leads to a tubular cytopharynx 11-32

33. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Major Protozoan Taxa Fecal material discharged from the cytoproct 2 contractile vacuoles Kidney-shaped macronucleus with smaller micronucleus alongside Some species have up to seven micronuclei Holozoic Body is elastic Can bend and squeeze through spaces 11-33

34. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Major Protozoan Taxa Phylum Dinoflagellata –About half are photoautotrophic –Chloroplasts possibly acquired by endosymbiosis –Some among the most important primary producers in marine environments –Commonly have two flagella –Body naked or covered by cellulose plates –Many have a mouth region through which they can ingest prey –Many are bioluminescent –Zooxanthellae Live in mutualistic association with corals and other invertebrates Only corals with symbiotic zooxanthellae form coral reefs 11-34

35. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-35

36. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Major Protozoan Taxa Phylum Apicomplexa –Plasmodium: The Malarial Organism »Most important infectious disease of humans »Four species infect humans »Each produces different clinical symptoms »Anopheles mosquitoes carry all forms »Female injects the Plasmodium present in her saliva »Migrate to the mosquito’s salivary gland where they are injected into a human host 11-36

37. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-37

38. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Major Protozoan Taxa Amoebas Found in fresh and salt water, and moist soils Some planktonic, some require a substratum Most reproduce by binary fission Nutrition is holozoic 11-38

39. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Major Protozoan Taxa Limestone and chalk deposits have been laid down by foraminiferan accumulations Chalk deposits of many areas of England, including White Cliffs of Dover, formed in this way. 11-39

40. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-40

41. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Major Protozoan Taxa Radiolarian Refers to marine testate amoeba with intricate skeletons Oldest known protozoa Pelagic and live in shallow water Shell surface fused with spines Cytoplasm around the capsule extends axopodia to catch prey Reproduce by binary fission & budding Useful for determining the age of rock strata 11-41

42. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 11-42

43. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. CHAPTER 6 Sponges 12-43

44. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera General Features Sessile sponges are filter feeders Porifera means “pore ‑ bearing” –Sac-like bodies perforated by many pores Use flagellated “collar cells”, or choanocytes, to move water Body is efficient aquatic filter Approximately 15,000 species of sponges –Most are marine Few live in brackish water, 150 in fresh water 12-44

45. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera Marine sponges found in all seas at all depths and vary greatly in size Many species are brightly colored because of pigments in dermal cells Embryos are free-swimming, adult sponges always attached Some appear radially symmetrical but many are irregular in shape Some stand erect, some are branched, and some are encrusting 12-45

46. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 12-46

47. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera Form and Function Body openings consist of small incurrent pores or dermal ostia Incurrent pores: Average diameter of 50 μm Inside the body –Water is directed past the choanocytes where food particles are collected –Choanocytes (flagellated collar cells) line some of the canals Keep the current flowing by beating of flagella Trap and phagocytize food particles passing by 12-47

48. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera Sponges non-selectively consume food particles sized between 0.1 μm and 50 μm –The smallest particles are taken into choanocytes by phagocytosis –Protein molecules may be taken in by pinocytosis –Two other cell types, pinacocytes and archaeocytes, play a role in sponge feeding 12-48

49. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 12-49

50. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera Types of Canal Systems –Asconoids: Flagellated Spongocoels Simplest body form Small and tube-shaped Water enters a large cavity, the spongocoel –Lined with choanocytes –Choanocyte flagella pull water through –All Calcarea are asconoids »Leucosolenia 12-50

51. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 12-51

52. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera –Syconoids: Flagellated Canals Resemble asconoids but larger with a thicker body wall Wall contains choanocyte-lined radial canals that empty into spongocoel –Water enters radial canals through tiny openings called prosopyles Spongocoel is lined with epithelial cells rather than choanocytes Food is digested by choanocytes 12-52

53. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 12-53

54. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera Leuconoids: Flagellated Chambers –Most complex and are larger with many oscula –Clusters of flagellated chambers are filled from incurrent canals, and discharge to excurrent canals –Most sponges are leuconoid –System increases flagellated surfaces compared to volume More collar cells can meet food demands Large sponges filter 1500 liters of water per day 12-54

55. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 12-55

56. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera Types of Cells –Sponge cells are arranged in a gelatinous matrix, mesohyl Connective “tissue” of sponges Absence of true tissues or organs requires that all fundamental processes occur at the level of individual cells –Only visible activities of sponges are Slight alterations in shape, local contraction, propagating contractions, and closing and opening of incurrent and excurrent pores Movements occur very slowly 12-56

57. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 12-57

58. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera –Pinacocytes Form pinacoderm Flat epithelial-like cells Somewhat contractile Some are myocytes that help regulate flow of water 12-58

59. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera –Choanocytes Oval cells with one end embedded in mesohyl Exposed end has one flagellum surrounded by a collar Collar consists of adjacent microvilli –Forms a fine filtering device to strain food –Particles too large to enter collar are trapped in mucous –Moved to the choanocyte and phagocytized –Food engulfed by choanocytes is passed to archaeocytes for digestion 12-59

60. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera –Archaeocytes Move about in the mesohyl Phagocytize particles in the pinacoderm Can differentiate into any other type of cell –Sclerocytes secrete spicules –Spongocytes secrete spongin –Collencytes secrete fibrillar collagen –Lophocytes secrete collagen 12-60

61. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera Class Calcarea Calcareous sponges with spicules of calcium carbonate Spicules are straight or have three or four rays Most are small with tubular or vase shapes Many are drab in color, but some are bright yellow, green, red, or lavender Leucosolenia and Sycon are marine shallow- water Asconoid, syconoid and leuconoid body forms 12-61

62. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera Class Hexactinellida Glass sponges with six-rayed spicules of silica Nearly all are deep-sea forms Most are radially symmetrical 12-62

63. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Porifera Class Demospongiae Spicules are siliceous but not six rayed Absent or bound together by spongin Leuconoid body form All marine except for Spongillidae, the freshwater sponges Freshwater sponges Widely distributed in well-oxygenated ponds and springs Marine demosponges Highly varied in color and shape Bath sponges Lacks siliceous spicules Have spongin skeletons 12-63

64. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 12-64

65. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. CHAPTER 7 Radiate Animals Radiate Animals 13-65

66. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Over 9,000 species in the phylum Cnidaria Equipped with specialized cells: cnidocytes Contain a specialized stinging organelle, the nematocyst Fossil specimens dated to over 700 million years ago Extant species Most common in shallow marine environments Some freshwater None are terrestrial 13-66

67. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Some ctenophores, molluscs and flatworms eat hydroids and use the stinging nematocysts for their own defense Four classes of Cnidaria Hydrozoa Scyphozoa Cubozoa Anthozoa 13-67

68. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Characteristics of Phylum Cnidaria All are aquatic and mostly marine Symmetry Radial or biradial Two body types Free-swimming medusae Sessile polyps Diploblastic Epidermis and gastrodermis Mesoglea: extracellar matrix that lies between ectodermis and gastrodermis 13-68

69. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Incomplete gut: gastrovascular cavity Extracellular digestion in gastrovascular cavity Intracellular digestion in gastrodermal cells Tentacles usually encircle mouth or oral region Muscular contractions via epitheliomuscular cells Outer layer of longitudinal fibers and an inner layer of circular fibers Sense organs for balance (statocysts) and photosensitivity (ocelli) 13-69

70. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Nerve net Asexual reproduction Budding in polyps Sexual reproduction By gametes in all medusae and some polyps No excretory or respiratory system Acoelomate 13-70

71. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-71

72. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Form and Function Cnidaria have two basic body plans: polyp and medusa –Polyp Hydroid form Adaptation to a sedentary life Tubular body with the mouth directed upward and surrounded by tentacles Mouth leads into a blind gastrovascular cavity Aboral end attached to substratum by pedal disc 13-72

73. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria –Medusa Bell or umbrella ‑ shaped Usually free-swimming Mouth directed downward Tentacles may extend down from rim of umbrella 13-73

74. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-74

75. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Life Cycles Polyps and medusae play different roles in the cnidarian life cycle Typically, zygote develops into a motile planula larva Planula settles, and metamorphoses into a polyp –Produce other polyps asexually –Polyps eventually produce a free-swimming medusa by asexual reproduction 13-75

76. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Body Wall Cnidarian body Outer epidermis Inner gastrodermis Layers separated by mesoglea Mesoglea Gelatinous (at least 95% water) Continuous in polyps, extending through body and tentacles Supports body 13-76

77. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Epitheliomuscular cells Form most of epidermis and cause muscular contraction Undifferentiated interstitial cells Develop into cnidoblasts, sex cells, buds, or nerve cells, but not epitheliomuscular cells. Gland cells On the adhesive disc secrete an adhesive and sometimes a gas bubble for floating 13-77

78. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Mechanism of Nematocyst Discharge When stimulated, water to rush into the capsule The operculum opens and rapidly launches the filament Barbs inject venom into prey Only a few jellyfish and the Portuguese man-of-war can seriously harm humans 13-78

79. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-79

80. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Nerve Net Nerve net of cnidarians one of the best examples of diffuse nervous system –Two nerve nets, one at the base of epidermis and one at the base of gastrodermis, interconnect Nerve action potentials transmitted across synapses by neurotransmitters Unlike higher animals, –Nerve nets have neurotransmitters on both sides of the synapses –Allowing transmission in either direction –No myelin sheath on axons 13-80

81. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Class Hydrozoa Most marine and colonial with both polyp and medusa forms Hydra is not typical Colonial Obelia is more exemplary In Obelia, the medusae buds are formed by a reproductive polyp called a gonangium Hydroid medusae Usually smaller than schyphozoan medusae Typically also bears statocysts, specialized sense organs that function in equilibrium, and light-sensitive ocelli 13-81

82. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-82

83. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-83

84. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-84

85. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-85

86. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Other Hydrozoans In Physalia, the float, pneumatophore –Thought to have expanded from the original larval polyp 13-86

87. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-87

88. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Class Scyphozoa Most of the larger jellyfishes belong to this class Nearly all float in open sea Bells vary in shape and size Composed mostly of mesoglea Mouth located beneath the umbrella Manubrium forms four oral arms Capture and ingest prey Tentacles, manubrium, and often entire body may have nematocysts 13-88

89. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-89

90. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-90

91. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Sexes are separate Fertilization is internal in the gastric pouch of the female Zygote develops into a ciliated planula larva Attaches and develops into a scyphistoma Scyphistoma undergoes strobilation Form buds called ephyrae that break loose to form jellyfish medusae 13-91

92. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-92

93. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Class Staurozoa Commonly called stauromedusans No medusa stage Solitary polyp body that is stalked Uses adhesive disk to attach to seaweeds, and objects on sea bottom Polyp top resembles a medusa with eight extensions (“arms”) ending in tentacle clusters surrounding mouth Reproduce sexually 13-93

94. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-94

95. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Class Cubozoa Medusa form is dominant Polyp is inconspicuous or unknown Umbrella is square One or more tentacles extend from each corner Umbrella edge turns inward to form a velarium Increases swimming efficiency Strong swimmers Feed mostly on fish in nearshore areas 13-95

96. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-96

97. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Class Anthozoa Lack a medusa stage All marine, in both deep and shallow water, and vary in size The mesoglea is mesenchyme containing ameboid cells No special organs for respiration or excretion Sea Anemones Polyps larger and heavier than hydrozoan polyps Attach to shells, rocks, timber, etc. by pedal discs 13-97

98. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-98

99. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-99

100. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-100

101. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-101

102. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Hexacorallian Corals Members of the order Scleractinia Also called true or stony corals Described as miniature sea anemones that live in calcareous cups they have secreted Sheet of living tissue forms over the coral surface –Connects all gastrovascular cavities 13-102

103. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-103

104. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-104

105. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-105

106. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Cnidaria Octocorallian Corals Octomerous symmetry, –Eight pinnate tentacles –Eight unpaired complete septa All are colonial –Gastrovascular cavities communicate through tubes called solenia –Solenia pass through an extensive mesoglea Show great variation in form of colony 13-106

107. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-107

108. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-108

109. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Ctenophora Phylum composed of about 150 species All marine, most prefer warm waters Ctenophores –Eight rows of comb-like plates used for locomotion Nearly all free-swimming, few creep or are sessile Body structure (ellipsoid or spherical shape) 13-109

110. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-110

111. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 13-111

112. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Ctenophora Tentacles –Two tentacles are long, solid and extensible –Retract into a pair of tentacle sheaths –Surface bears colloblasts or glue cells that secrete sticky material to hold animals Body wall resembles cnidarians with a gelatinous collenchyme in the interior Muscle cells are distinct and not part of the epitheliomuscular cells 13-112

113. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Phylum Ctenophora When ctenophore contacts an unfavorable stimulus Cilia reverse their beat Moves organisms backward Comb plates are sensitive to touch Withdraw into the animal when touched Most ctenophores are bioluminescent at night 13-113