1. The Animal Kingdom: An Introduction to Animal Diversity Chapter 29

2. Learning Objective 1 What characters are common to most animals? What characters are common to most animals?

3. Kingdom Animalia Eukaryotic Eukaryotic Multicellular Multicellular Heterotrophic Heterotrophic Cells specialized for specific functions Cells specialized for specific functions

4. Structure Body plan Body plan basic structure and functional design of body basic structure and functional design of body Animals have diverse body plans Animals have diverse body plans

5. Function Most animals Most animals are capable of locomotion at some time during life cycle are capable of locomotion at some time during life cycle can respond adaptively to external stimuli can respond adaptively to external stimuli can reproduce sexually can reproduce sexually

6. Sexual Reproduction Sperm and egg unite (zygote) Sperm and egg unite (zygote) Zygote undergoes cleavage Zygote undergoes cleavage cell divisions produce hollow ball of cells (blastula) cell divisions produce hollow ball of cells (blastula) Blastula undergoes gastrulation Blastula undergoes gastrulation forms embryonic tissues forms embryonic tissues

7. KEY CONCEPTS Animals are multicellular, eukaryotic heterotrophs Animals are multicellular, eukaryotic heterotrophs

8. Explore the characteristics of animals by clicking on the figures in ThomsonNOW.

9. Learning Objective 2 Compare the advantages and disadvantages of life in the ocean, in fresh water, and on land Compare the advantages and disadvantages of life in the ocean, in fresh water, and on land

10. Marine Environments Provide Provide relatively stable temperatures relatively stable temperatures buoyancy buoyancy readily available food readily available food Fluid and salt balance Fluid and salt balance more easily maintained than in fresh water more easily maintained than in fresh water Disadvantages: Disadvantages: currents and other water movements currents and other water movements

11. Fresh Water Provides Provides less constant environment less constant environment less food less food Animals must osmoregulate Animals must osmoregulate fresh water is hypotonic to tissue fluid fresh water is hypotonic to tissue fluid

12. Terrestrial Animals Have adaptations that Have adaptations that protect them from drying out protect them from drying out protect them from temperature changes protect them from temperature changes protect their gametes and embryos protect their gametes and embryos

13. Marine and Terrestrial Environments

14. Learning Objective 3 Use current hypotheses to trace the early evolution of animals Use current hypotheses to trace the early evolution of animals

15. Hypotheses Proterozoic eon Proterozoic eon most animal clades diverged over long period most animal clades diverged over long period based on molecular data based on molecular data Cambrian Radiation Cambrian Radiation new body plans rapidly evolved among clades new body plans rapidly evolved among clades first fossils of these animals first fossils of these animals

16. Hox Genes Hox gene group Hox gene group controls early development in animal groups controls early development in animal groups Cambrian period Cambrian period many Hox genes had evolved many Hox genes had evolved mutations could have resulted in rapid changes in animal body plans mutations could have resulted in rapid changes in animal body plans

17. Learning Objective 4 How do biologists use structural characters (variations in body symmetry, number of tissue layers, type of body cavity) and patterns of early development to infer relationships among animal phyla? How do biologists use structural characters (variations in body symmetry, number of tissue layers, type of body cavity) and patterns of early development to infer relationships among animal phyla?

18. Symmetry Cnidarians and ctenophores are closely related Cnidarians and ctenophores are closely related because they share radial symmetry because they share radial symmetry most other animals exhibit bilateral symmetry most other animals exhibit bilateral symmetry Cephalization (development of head) Cephalization (development of head) evolved with bilateral symmetry evolved with bilateral symmetry

19. Radial and Bilateral Symmetry

20. Fig. 29-3a, p. 623 Radial symmetry (top view)

21. Fig. 29-3b, p. 623 Radial symmetry (side view)

22. Fig. 29-3c, p. 623 Dorsal Frontal section Caudal Anterior Posterior Cephalic Ventral Cross (or transverse) section Bilateral symmetry (lateral view)

23. Fig. 29-3d, p. 623 Dorsal Sagittal section Medial Frontal section Lateral Ventral Bilateral symmetry (front view)

24. Insert “Types of body symmetry” symmetry.swf

25. Other Structural Characters Relationships can be based on Relationships can be based on level of tissue development level of tissue development type of body cavity type of body cavity Embryonic tissues (germ layers) Embryonic tissues (germ layers)

26. Coelom Formation

27. Fig. 29-6, p. 626 Schizocoely — characteristic of protostomes Enterocoely — characteristic of deuterostomes Ectoderm Developing mesoderm Blastopore Presumptive mesoderm Enterocoelic pouch Endoderm Mesoderm Ectoderm Endoderm GutEctoderm Developing coelom (Schizocoel) Endoderm Ectoderm Gut Mesoderm Gut Coelom (Enterocoel) GutMesoderm Coelom Endoderm Mesentery Epidermis (ectoderm)Coelom Peritoneum (mesoderm) Muscle layer (mesoderm) Gut

28. Fig. 29-6, p. 626 Stepped Art Schizocoely — characteristic of protostomes Enterocoely — characteristic of deuterostomes Ectoderm Developing mesoderm Blastopore Presumptive mesoderm Enterocoelic pouch Endoderm Mesoderm Ectoderm Endoderm Gut Ectoderm GutMesoderm Coelom Epidermis (ectoderm) Endoderm Mesentery Coelom Peritoneum (mesoderm) Muscle layer (mesoderm) Gut Developing coelom (Schizocoel) Endoderm Ectoderm Mesoderm Gut Coelom (Enterocoel)

29. Germ Layers Outer layer (ectoderm) Outer layer (ectoderm) gives rise to body covering, nervous system gives rise to body covering, nervous system Inner layer (endoderm) Inner layer (endoderm) lines the gut and other digestive organs lines the gut and other digestive organs Middle layer (mesoderm) Middle layer (mesoderm) gives rise to most other body structures gives rise to most other body structures

30. Body Plans

31. Fig. 29-4a, p. 624 Epidermis (from ectoderm) Muscle layer (from mesoderm) (a) Acoelomate—flatworm (liver fluke). Mesenchyme (gelatin-like tissue) Epithelium (from endoderm)

32. Fig. 29-4b, p. 624 Pseudocoelom Epidermis (from ectoderm) Muscle layer (from mesoderm) Epithelium (from endoderm) (b) Pseudocoelomate—nematode.

33. Fig. 29-4c, p. 624 Coelom Epidermis (from ectoderm) Muscle layer (from mesoderm) Peritoneum (from mesoderm) Epithelium (from endoderm) Mesentery (from mesoderm) (c) True coelomate—vertebrate.

34. Insert “Types of body cavities” coelom.swf

35. Bilateral Symmetry Acoelomate Acoelomate no body cavity no body cavity Pseudocoelomate Pseudocoelomate body cavity not completely lined with mesoderm body cavity not completely lined with mesoderm Coelomate, (animal with true coelom) Coelomate, (animal with true coelom) body cavity completely lined with mesoderm body cavity completely lined with mesoderm

36. Bilateral Animals Two major evolutionary branches: Two major evolutionary branches: Protostomia Protostomia mollusks, annelids, arthropods mollusks, annelids, arthropods Deuterostomia Deuterostomia echinoderms, chordates echinoderms, chordates

37. Blastopore Opening from embryonic gut to outside Opening from embryonic gut to outside In protostomes In protostomes develops into the mouth develops into the mouth In deuterostomes In deuterostomes becomes the anus becomes the anus

38. Cleavage 1 Protostomes Protostomes undergo spiral cleavage undergo spiral cleavage early cell divisions diagonal to polar axis early cell divisions diagonal to polar axis Deuterostomes Deuterostomes undergo radial cleavage undergo radial cleavage early cell divisions either parallel or at right angles to polar axis early cell divisions either parallel or at right angles to polar axis cells lie directly above or below one another cells lie directly above or below one another

39. Spiral and Radial Cleavage

40. Fig. 29-5a, p. 625 Polar axis Top view Spiral cleavage

41. Fig. 29-5b, p. 625 Top view Polar axis Radial cleavage

42. Cleavage 2 Protostomes Protostomes undergo determinate cleavage undergo determinate cleavage fate of each embryonic cell is fixed very early fate of each embryonic cell is fixed very early Deuterostomes Deuterostomes undergo indeterminate cleavage undergo indeterminate cleavage fate of each embryonic cell is more flexible fate of each embryonic cell is more flexible

43. Relationships Based on Structure

44. Fig. 29-7, p. 627 Parazoa Eumetazoa RadiataBilateria AcoelomatesPseudocoelomates Coelomates Protostomia Deuterostomia Choanoflagellates Porifera Cnidaria Ctenophora Platyhelminthes NemerteaNematoda Rotifera TardigradaOnychophoraArthropodaAnnelidaMolluscaEchinodermataHemichordata Chordata Segmentation Deuterostome development Pseudocoelom True coelom Radial symmetry Protostome development Tissues (ectoderm and endoderm) Multicellularity Choanoflagellate ancestor Three tissue layers (mesoderm) Bilateral symmetry

45. KEY CONCEPTS Biologists classify animals based on their body plan and features of their early development Biologists classify animals based on their body plan and features of their early development

46. Learning Objective 5 What are three major contributions to animal phylogeny made by molecular systematics? What are three major contributions to animal phylogeny made by molecular systematics? Identify the three major clades of bilateral animals Identify the three major clades of bilateral animals

47. Molecular Systematics 1 Confirmed much of animal phylogeny based on structural characters Confirmed much of animal phylogeny based on structural characters including axiom that animal body plans usually evolved from simple to complex including axiom that animal body plans usually evolved from simple to complex

48. Molecular Systematics 2 Provided evidence for exceptions to “simple-to-complex” rule Provided evidence for exceptions to “simple-to-complex” rule Example Example molecular data indicate flatworms and ribbon worms evolved from more complex animals, became simpler over time molecular data indicate flatworms and ribbon worms evolved from more complex animals, became simpler over time

49. Molecular Systematics 3 Molecular data suggest pseudocoelomate animals do not form natural group Molecular data suggest pseudocoelomate animals do not form natural group probably evolved from coelomate ancestors probably evolved from coelomate ancestors

50. Protostomes 2 clades based on molecular data: 2 clades based on molecular data: Lophotrochozoa Lophotrochozoa flatworms, ribbon worms, mollusks, annelids, lophophorate phyla, rotifers flatworms, ribbon worms, mollusks, annelids, lophophorate phyla, rotifers Ecdysozoa (animals that molt) Ecdysozoa (animals that molt) nematodes and arthropods nematodes and arthropods

51. 3 Clades of Bilateral Animals Lophotrochozoa Lophotrochozoa Ecdysozoa Ecdysozoa Deuterostomia Deuterostomia

52. Relationships Based on Molecular Data

53. Fig. 29-8a, p. 629 ParazoaEumetazoa Radiata Bilateria Protostomia Deuterostomia Lophotrochozoa Ecdysozoa Choanoflagellates Porifera Cnidaria CtenophoraPlatyhelminthes NemerteaMollusca AnnelidaLophophorate phyla RotiferaNematodaTardigradaOnychophoraArthropodaEchinodermataHemichordataChordata Segmentation Deuterostome pattern of development Protostome pattern of development Radial symmetry Bilateral symmetry, three tissue layers, body cavity Tissues Multicellularity Choanoflagellate ancestor

54. Fig. 29-8b, p. 629 Parazoa Radiata Ecdysozoa Lophotrochozoa Deuterostomia Choanoflagellate ancestor

55. KEY CONCEPTS Molecular data indicate that bilateral animals split into three major clades: Molecular data indicate that bilateral animals split into three major clades: two protostome groups—Lophotrochozoa (such as flatworms, mollusks, and annelids) and Ecdysozoa (such as nematodes and arthropods)—and deuterostomes (echinoderms and chordates) two protostome groups—Lophotrochozoa (such as flatworms, mollusks, and annelids) and Ecdysozoa (such as nematodes and arthropods)—and deuterostomes (echinoderms and chordates)

56. Learning Objective 6 What are the distinguishing characteristics of phylum Porifera? What are the distinguishing characteristics of phylum Porifera?

57. Phylum Porifera Sponges Sponges animals characterized by flagellate collar cells (choanocytes) animals characterized by flagellate collar cells (choanocytes) The only members of the Parazoa The only members of the Parazoa sister group of Eumetazoa sister group of Eumetazoa

58. Sponge Structure Sponge body Sponge body sac with tiny openings for water to enter sac with tiny openings for water to enter central cavity (spongocoel) central cavity (spongocoel) open end (osculum) for water to exit open end (osculum) for water to exit Sponge cells Sponge cells loosely associated loosely associated do not form true tissues do not form true tissues

59. Sponge Structure

60. Choanoflagellate ancestor Fig. 29-9a, p. 630 Parazoa Porifera RadiataLophotrochozoa Ecdysozoa Deuterostomia

61. Fig. 29-9b, p. 630 Osculum Spongocoel Incurrent pores Water movement Epidermal cell Porocyte Spicule Microvillus Flagellum Amoeboid cell in mesohyl Nucleus Collar cell Collar

62. KEY CONCEPTS Sponges (phylum Porifera) are characterized by collar cells and by loosely associated cells that do not form true tissues Sponges (phylum Porifera) are characterized by collar cells and by loosely associated cells that do not form true tissues

63. Insert “Body plan of a sponge” sponge_body.swf

64. Learn more about sponge structure by clicking on the figure in ThomsonNOW.

65. Learning Objective 7 What are the distinguishing characteristics of phylum Cnidaria? What are the distinguishing characteristics of phylum Cnidaria? Describe four classes of this phylum Describe four classes of this phylum Give examples of animals that belong to each class Give examples of animals that belong to each class

66. Phylum Cnidaria 1 Characterized by Characterized by radial symmetry radial symmetry two tissue layers two tissue layers cnidocytes (cells containing nematocysts) cnidocytes (cells containing nematocysts)

67. Nematocysts

68. Fig. 29-11b, p. 634 Cnidocyte Nucleus Thread Capsule Nematocyst (not discharged) Cnidocil (trigger) Thread Nematocyst (discharged)

69. Insert “Nematocyst action” nematocyst_v2.swf

70. Phylum Cnidaria 2 Gastrovascular cavity Gastrovascular cavity with single opening for mouth and anus with single opening for mouth and anus Nerve cells form irregular, nondirectional nerve nets Nerve cells form irregular, nondirectional nerve nets connect sensory cells with contractile and gland cells connect sensory cells with contractile and gland cells

71. Cnidarian Structure Hydra Hydra

72. Fig. 29-12, p. 634 Tentacles Cnidocytes (stinging cells) 1 mm Mouth Egg (ovum) Bud Gastrovascular cavity Ovary Epidermis Mesoglea Gastrodermis

73. Cnidaria Life Cycle Sessile polyp stage Sessile polyp stage form with dorsal mouth surrounded by tentacles form with dorsal mouth surrounded by tentacles Free-swimming medusa (jellyfish) stage Free-swimming medusa (jellyfish) stage

74. Cnidaria Life Cycle Obelia Obelia

75. Fig. 29-13b, p. 635 1 Reproductive polyps produce medusae by budding asexually Mouth Medusae Tentacle Feeding polyp 2 Free-swimming medusae reproduce sexually. Medusa bud Egg Sperm Reproductive polyp Gastrovascular cavity 3 Zygote develops into ciliated planula larva. Planula larva Polyp colony 4 Larva develops into polyp that forms new colony. 5 Colony grows as new polyps bud and remain attached. Young polyp colony (b) Life cycle of Obelia.

76. 4 Classes of Phylum Cnidaria 1. Class Hydrozoa (hydras, hydroids, Portuguese man-of-war) typically polyps typically polyps may be solitary or colonial may be solitary or colonial 2. Class Scyphozoa (jellyfish) generally medusae generally medusae

77. 4 Classes of Phylum Cnidaria 3. Class Cubozoa (“box jellyfish”) have complex eyes that form blurred images have complex eyes that form blurred images 4. Class Anthozoa (sea anemones, corals) polyps polyps may be solitary or colonial may be solitary or colonial differ from hydrozoans in organization of gastrovascular cavity differ from hydrozoans in organization of gastrovascular cavity

78. Cnidarians

79. Fig. 29-10 (1), p. 633 Radiata ParazoaCnidaria Ctenophora Lophotrochozoa EcdysozoaDeuterostomia Choanoflagellate ancestor

80. Fig. 29-10a, p. 633 Mouth Epidermis Mesoglea Gastrodermis Gastrovascular cavity Class Hydrozoa (polyp)

81. Fig. 29-10b, p. 633 Mouth Mesoglea Gastrodermis Epidermis Gastrovascular cavity Class Scyphozoa (medusa)

82. Fig. 29-10c, p. 633 Mouth Epidermis Mesoglea Gastrodermis Gastrovascular cavity Class Anthozoa (polyp)

83. Insert “Cnidarian body plans” cnidarian_bodies.swf

84. KEY CONCEPTS Members of phylum Cnidaria (hydras, jellyfish, sea anemones) are characterized by radial symmetry, two tissue layers, and cnidocytes, cells that contain stinging organelles Members of phylum Cnidaria (hydras, jellyfish, sea anemones) are characterized by radial symmetry, two tissue layers, and cnidocytes, cells that contain stinging organelles

85. Insert “Cnidarian life cycle” obelia_life_cycle.swf

86. Learn more about cnidarian body forms, nematocysts, and life cycles by clicking on the figures in ThomsonNOW.

87. Learning Objective 8 What are the distinguishing characteristics of phylum Ctenophora? What are the distinguishing characteristics of phylum Ctenophora?

88. Phylum Ctenophora Comb jellies Comb jellies fragile, luminescent marine predators fragile, luminescent marine predators biradial symmetry biradial symmetry eight rows of cilia that resemble combs eight rows of cilia that resemble combs tentacles with adhesive glue cells tentacles with adhesive glue cells

89. Comb Jelly

90. KEY CONCEPTS Members of phylum Ctenophora (comb jellies) have biradial symmetry, two tissue layers, eight rows of cilia, and tentacles with adhesive glue cells Members of phylum Ctenophora (comb jellies) have biradial symmetry, two tissue layers, eight rows of cilia, and tentacles with adhesive glue cells