1. Invertebrates Chapter 33

2. Animal Origins

3. Chlorophyta Plantae Ancestral eukaryote Rhodophyta Fungi Diplomonadida Parabasala Euglenozoa AlveolataStramenopila Cercozoa Radiolaria Amoebozoa Animalia Choanoflagellates Figure 28.4

4. Characteristics of the Animal Kingdom None of the following are unique to animals, but together distinguish animals from other organisms: Multicellular Heterotrophic No cell walls Motile during some stage(s) in life

5. A great diversity of body plans occur; some key features include: Organized federation of cells vs. cells in tissues Characteristics of the Animal Kingdom Tissue – integrated group of cells with a common structure and function Tissues are generally further integrated into organs Organs are generally further integrated into organ systems

6. A great diversity of body plans occur; some key features include: For organisms with tissues: two vs. three principal embryonic tissues Characteristics of the Animal Kingdom

7. Two embryonic tissue layers: Characteristics of the Animal Kingdom Fig. 32.2 Zygote Blastula Gastrulatio n Gastrula Blastocoel Endoderm Ectoderm Blastopore Archenteron

8. Two embryonic tissue layers: Characteristics of the Animal Kingdom Gastrula Blastocoel Endoderm Ectoderm Blastopore Archenteron Endoderm – Innermost “germ layer”; differentiates into some of the internal tissues and the lining of most hollow organs, if these are present Ectoderm – Outermost “germ layer”; differentiates into tissues that cover the body and into the nervous tissues Fig. 32.2

9. Three embryonic tissue layers: Characteristics of the Animal Kingdom Endoderm – Innermost “germ layer”; differentiates into some of the internal tissues and the lining of most hollow organs, if these are present Mesoderm – Middle “germ layer”; differentiates into muscles, circulatory and skeletal systems, and sex organs, if these are present Ectoderm – Outermost “germ layer”; differentiates into tissues that cover the body and into the nerve tissues Fig. 32.9

10. Characteristics of the Animal Kingdom A great diversity of body plans occur; some key features include: Radial vs. bilateral symmetry Any plane that passes through the central axis produces roughly mirror-image halves A single midline plane produces roughly mirror-image halves; generally accompanied by distinct cephalization Fig. 32.7

11. Among organisms with 3 germ layers: Acoelomate, pseudocoelomate, or coelomate Characteristics of the Animal Kingdom A great diversity of body plans occur; some key features include:

12. Among organisms with 3 germ layers: Acoelomate, pseudocoelomate, or coelomate Characteristics of the Animal Kingdom A great diversity of body plans occur; some key features include: Acoelomate: lack a coelom, i.e., lack a body cavity between digestive track and body wall Fig. 32.8

13. Among organisms with 3 germ layers: Acoelomate, pseudocoelomate, or coelomate Characteristics of the Animal Kingdom A great diversity of body plans occur; some key features include: Pseudocoelomate: Fluid-filled body cavity between digestive tract and body wall partially lined by mesoderm Fig. 32.8

14. Among organisms with 3 germ layers: Acoelomate, pseudocoelomate, or coelomate Characteristics of the Animal Kingdom A great diversity of body plans occur; some key features include: Coelomate: fluid-filled body cavity between digestive tract and body wall completely lined by mesoderm Fig. 32.8

15. Characteristics of the Animal Kingdom A great diversity of body plans occur; some key features include: Protostome vs. deuterostome development

16. Characteristics of the Animal Kingdom A great diversity of body plans occur; some key features include: Protostome vs. deuterostome development See Fig. 32.9

17. The Animal Kingdom ~ 35 phyla Calcarea Silicarea Ctenophora Cnidaria Echinodermata Chordata Brachiopoda Phoronida Ectoprocta Platyhelminthes Nemertea Mollusca Annelida Rotifera Nematoda Arthropoda “Radiata” “Porifera” Deuterostomia Lophotrochozoa Ecdysozoa Bilateria Eumetazoa Metazoa Ancestral colonial flagellate Fig. 32.11 & Table 33.7

18. Phylum Porifera – Sponges Ancestral colonial choanoflagellate Eumetazoa Bilateria Deuterostomia Porifera Cnidaria Other bilaterians (including Nematoda, Arthropoda, Mollusca, and Annelida) Echinodermata Chordata Figure 33.2

19. Organized aggregation of cells Probably the most similar extant group to the protistan colonial precursors to the animals Phylum Porifera – Sponges

20. Organized aggregation of cells Three main cell types, but no true tissues Asymmetric body plan Mostly marine, but some inhabit fresh water Phylum Porifera – Sponges

21. Internal skeleton of protein spicules E.g., natural bath sponge Phylum Porifera – Sponges

22. Eumetazoa All animals except sponges belong to the clade Eumetazoa All eumetazoans have true tissues Ancestral colonial choanoflagellate Eumetazoa Bilateria Deuterostomia Porifera Cnidaria Other bilaterians (including Nematoda, Arthropoda, Mollusca, and Annelida) Echinodermata Chordata Figure 33.2

23. Phylum Cnidaria – Corals, Jellyfish, Anemones Radially symmetric animals with 2 germ layers (true tissues), but generally lacking true organs Gastrovascular cavity; mouth and anus are the same opening Rudimentary nerve net and contractile tissue

24. Tentacles contain cnidocytes Fig. 33.6 Phylum Cnidaria – Corals, Jellyfish, Anemones

25. Polyp and medusa forms Fig. 33.5 Phylum Cnidaria – Corals, Jellyfish, Anemones

26. Polyp and medusa forms Phylum Cnidaria – Corals, Jellyfish, Anemones

27. Phylum Ctenophora – Comb jellies 8 rows of comblike plates of cilia

28. Bilateria Bilaterally symmetric, cephalized animals with 3 germ layers Ancestral colonial choanoflagellate Eumetazoa Bilateria Deuterostomia Porifera Cnidaria Other bilaterians (including Nematoda, Arthropoda, Mollusca, and Annelida) Echinodermata Chordata Figure 33.2

29. Gastrovascular cavity (if a gut is present) P. Platyhelminthes – Flat worms Some true organs are present (tissues grouped into functional structures) Hermaphroditic and capable of self-fertilization Acoelomate

30. Mostly free-living P. Platyhelminthes – Flat worms

31. Mostly free-living P. Platyhelminthes – Flat worms Some parasitic E.g., tapeworms

32. Distinguishing feature is a “crown of cilia” around the mouth P. Rotifera – Rotifers Complete digestive tract surrounded by pseudocoelom Parthenogenesis (development from unfertilized eggs) is the most common mode of reproduction

33. P. Ectoprocta P. Phoronida P. Brachiopoda All bear a lophophore – fold of the body wall bearing ciliated tentacles surrounding the mouth Coelomate

34. P. Ectoprocta Colonial Many contribute to marine reefs a.k.a. bryozoans

35. P. Phoronida A group of tube-dwelling marine worms

36. P. Brachiopoda a.k.a. lamp shells Marine, mostly extinct

37. P. Nemertea a.k.a. proboscis or ribbon worms Structurally acoelomate, with a small fluid-filled sac that may be a vestigial coelom Closed circulatory system, but no heart

38. P. Mollusca a.k.a. mollusks

39. P. Mollusca a.k.a. mollusks Coelomate body with a muscular foot, visceral mass, and mantle (which secretes a shell in many species)

40. P. Mollusca a.k.a. mollusks 8 classes, including: C. Polyplacophora (chitons) Shell divided into 8 plates

41. P. Mollusca a.k.a. mollusks 8 classes, including: C. Gastropoda (snails and slugs) Single shell or lacking shell

42. P. Mollusca a.k.a. mollusks 8 classes, including: C. Gastropoda (snails and slugs) Single shell or lacking shell

43. P. Mollusca a.k.a. mollusks 8 classes, including: C. Bivalvia (clams, oysters, mussels, etc.) Hinged, two- part shell

44. P. Mollusca a.k.a. mollusks 8 classes, including: C. Cephalopoda (squids, octopuses, nautiluses) Only mollusks with closed circ. system and complex brain

45. P. Mollusca a.k.a. mollusks 8 classes, including: C. Cephalopoda (squids, octopuses, nautiluses) Only mollusks with closed circ. system and complex brain

46. P. Annelida a.k.a. segmented worms

47. P. Annelida a.k.a. segmented worms Segmented Coelomate Closed circulatory system Coelom

48. P. Annelida a.k.a. segmented worms 3 classes: C. Oligochaeta Earthworms and their kin Coelom

49. P. Annelida a.k.a. segmented worms 3 classes: C. Polychaeta Bristled parapodia on each segment

50. P. Annelida a.k.a. segmented worms 3 classes: C. Hirudinea Leeches

51. P. Nematomorpha a.k.a. horsehair or gordian worms Not required to know

52. P. Priapulida a.k.a. penis worms Not required to know

53. P. Tardigrada a.k.a. water bears Not required to know

54. P. Onychophora a.k.a. velvet worms Not required to know

55. P. Nematoda a.k.a. roundworms Nonsegmented

56. P. Nematoda a.k.a. roundworms Nonsegmented No circulatory or respiratory systems Mouth Gut Anus

57. P. Nematoda a.k.a. roundworms Nonsegmented No circulatory or respiratory systems Pseudocoelomate

58. P. Nematoda a.k.a. roundworms Nonsegmented No circulatory or respiratory systems Free living or parasitic Pseudocoelomate E.g., dog heartworm

59. P. Arthropoda Segmented Coelomate Exoskeleton of chitin Jointed appendages

60. P. Arthropoda Open circulatory system Hemolymph (the open-circulation system equivalent of blood) carries dissolved gases through short vessels and the hemocoel (main body cavity in adults, since coelom is reduced)

61. P. Arthropoda As in much of modern systematics, classes are in flux; nevertheless, here are 5 main groups: Trilobites – all extinct during Permain mass extinction ~250 mya

62. P. Arthropoda Cheliceriforms – horseshoe crabs

63. P. Arthropoda Cheliceriforms – sea spiders

64. P. Arthropoda Cheliceriforms: Arachnids – spiders, ticks, scorpions, mites

65. P. Arthropoda spider (tarantula) scorpion tick mite Cheliceriforms: Arachnids – spiders, ticks, scorpions, mites

66. P. Arthropoda Adults generally have 4 pairs of walking legs Some produce silk Cheliceriforms: Arachnids – spiders, ticks, scorpions, mites

67. P. Arthropoda Simple eyes (each with a single lens) Eyes of black widow spider Cheliceriforms: Arachnids – spiders, ticks, scorpions, mites

68. P. Arthropoda Myriapods – millipedes; 2 pairs of legs per segment

69. P. Arthropoda Myriapods – centipedes; 1 pair of legs per segment

70. P. Arthropoda Hexapods: insects

71. P. Arthropoda Adult often has 2 pairs of wings Hexapods: insects

72. P. Arthropoda Sometimes 1 pair of wings; sometimes none Hexapods: insects

73. P. Arthropoda Adult generally has 3 pairs of legs Hexapods: insects

74. P. Arthropoda Metamorphosis – transition between distinct (often dramatically different) developmental stages Larva (maggot, caterpillar) Pupa (transition to adult) Adult (often winged) Hexapods: insects

75. P. Arthropoda Metamorphosis – transition between distinct (often dramatically different) developmental stages Larva (maggot, caterpillar) Pupa (transition to adult) Adult (often winged) Hexapods: insects

76. P. Arthropoda Adult generally has compound eyes Hexapods: insects

77. Insects Some of the major orders (26 in total): Order Coleoptera Order Coleoptera – Beetles Order Hemiptera Order Hemiptera – True Bugs Order Homoptera Order Homoptera – Aphids and their kin Order Hymenoptera Order Hymenoptera – Ants, Bees, Wasps Order Isoptera Order Isoptera – Termites Order Lepidoptera Order Lepidoptera – Butterflies and Moths Order Odonata Order Odonata – Dragonflies and Damselflies Order Orthoptera Order Orthoptera – Crickets, Grasshoppers, Katydids Order Siphonaptera Order Siphonaptera – Fleas See also Fig. 33.37

78. P. Arthropoda Crustaceans As in all arthropods, crustaceans have segmented body plans

79. P. Arthropoda waterflea sowbug hermit crabbarnacle Crustaceans

80. P. Arthropoda Often have 5 or more pairs of legs Crustaceans

81. P. Arthropoda Generally have compound eyes Crustaceans

82. Deuterostomia Deuterostome developmental pathway Ancestral colonial choanoflagellate Eumetazoa Bilateria Deuterostomia Porifera Cnidaria Other bilaterians (including Nematoda, Arthropoda, Mollusca, and Annelida) Echinodermata Chordata Coelomates Figure 33.2

83. P. Echinodermata

84. At first glance they may seem more radially than bilaterally symmetrical…

85. P. Echinodermata However, their larvae are obviously bilaterally symmetrical Sea star larva Sea star adult

86. P. Echinodermata Sea cucumber Brittle star Sea urchin Sand dollar

87. P. Echinodermata Sea cucumber Brittle star Sand dollar Sea urchin Calcium carbonate endoskeleton

88. P. Echinodermata Unique water vascular system of hydraulic canals branching into tube feet for locomotion, feeding, and gas exchange

89. P. Chordata At some stage in development, all chordates possess: