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Chapter 33

Chapter 33. Invertebrates. Fig. 33-1. Overview: Life Without a Backbone. Invertebrates are animals that lack a backbone They account for 95% of known animal species. Fig. 33-2. Calcarea and Silicea. Sponges/ “Porifera”. ANCESTRAL PROTIST. Cnidaria. Mollusca/ Annelida. Common

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Chapter 33

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  1. Chapter 33 Invertebrates

  2. Fig. 33-1

  3. Overview: Life Without a Backbone • Invertebrates are animals that lack a backbone • They account for 95% of known animal species

  4. Fig. 33-2 Calcarea and Silicea Sponges/ “Porifera” ANCESTRAL PROTIST Cnidaria Mollusca/ Annelida Common ancestor of all animals Eumetazoa Nematoda/ Arthropoda Bilateria Chordata/ Echinodermata

  5. Fig. 33-3a A jelly A sponge Phylum Choanocytes Phylum Cnidaria (“Porifera”)

  6. Fig. 33-3a A marine flatworm A rotifer (LM) Phylum Platyhelminthes Phylum Rotifera

  7. Fig. 33-3m An octopus A marine annelid Phylum Mollusca Phylum Annelida

  8. Fig. 33-3s A scorpion (an arachnid) A roundworm Phylum Nematoda Phylum Arthropoda

  9. Fig. 33-3v A sea urchin A tunicate Phylum Echinodermata Phylum Chordata

  10. Concept 33.1: Sponges are basal animals that lack true tissues • Sponges are sedentary, filter feeding animals from the phyla Calcarea and Silicea “Porifera” • They live in both fresh and marine waters • Sponges lack true tissues and organs • Possess collar cells to propel water through the body and strain food particles. • Food digested intracellularly by amebocytes • Most asymmetrical • http://www.youtube.com/watch?v=RmPTM965-1c&feature=related(sponge feeding)

  11. Fig. 33-4 Food particles in mucus Flagellum Choanocyte Collar Choanocyte Osculum Azure vase sponge (Callyspongia plicifera) Spongocoel Phagocytosis of food particles Amoebocyte Pore Spicules Epidermis Water flow Amoebocytes Mesohyl

  12. Concept 33.2: Cnidarians are an ancient phylum of eumetazoans • All animals except sponges and a few other groups are animals with true tissues (Eumetazoa) • Phylum Cnidaria: jellies, corals, sea anemones • Radial symmetrical carnivores • Diplobastic - Two body layers: ectoderm & endoderm • Possess gastrovascular cavity (not a complete tube) and nematocysts • There are two variations on the body plan: the sessile polyp and motile medusa

  13. Fig. 33-5 Mouth/anus Tentacle Polyp Medusa Gastrovascular cavity Gastrodermis Mesoglea Body stalk Epidermis Tentacle Mouth/anus

  14. Fig. 33-6 Tentacle Cuticle of prey Thread Nematocyst “Trigger” Thread discharges Thread (coiled) Cnidocyte

  15. Fig. 33-7 (d) Sea anemone (class Anthozoa) (b) Jellies (class Scyphozoa) (c) Sea wasp (class Cubozoa) (a) Colonial polyps (class Hydrozoa)

  16. Conceptual Summary • Sponges and cnidarians are almost entirely marine and are considered primitive because they do not possess three body layers nor true organs • http://www.youtube.com/watch?v=zkF_1r6ll54&feature=related (hydra eating) • http://www.youtube.com/watch?v=a5oHMjGqjyo (budding in hydra)

  17. Fig. 33-8-1 Reproductive polyp Feeding polyp Medusa bud Medusa ASEXUAL REPRODUCTION (BUDDING) Portion of a colony of polyps 1 mm Key Haploid (n) Diploid (2n)

  18. Fig. 33-8-2 Reproductive polyp Feeding polyp Medusa bud MEIOSIS Gonad Medusa Egg Sperm SEXUAL REPRODUCTION ASEXUAL REPRODUCTION (BUDDING) Portion of a colony of polyps FERTILIZATION Zygote 1 mm Key Haploid (n) Diploid (2n)

  19. Fig. 33-8-3 Medusa produced by asexual budding Reproductive polyp Feeding polyp Medusa bud MEIOSIS Gonad Medusa Egg Sperm SEXUAL REPRODUCTION ASEXUAL REPRODUCTION (BUDDING) Portion of a colony of polyps FERTILIZATION Zygote Developing polyp 1 mm Planula (larva) Key Mature polyp Haploid (n) Diploid (2n)

  20. Platyhelminthes: Flatworms • Acoelomates – solid body, without a body cavity • Bilateral symmetry and beginnings of cephalization • Development of true organs, tripbloblastic (three body layers); ectoderm, endoderm, mesoderm • No coelom (body cavity) • Digestibe tract incomplete – only one opening that braches throughout the body to distribute food • http://www.youtube.com/watch?v=5fx-YgcP8Gg (flatworm mating behavior – Rated R)

  21. Fig. 33-9

  22. Fig. 33-10 Pharynx Gastrovascular cavity Mouth Eyespots Ganglia Ventral nerve cords

  23. Fig. 33-12 • Tapeworms are parasites of vertebrates and lack a digestive system • Tapeworms absorb nutrients from the host’s intestine • Fertilized eggs, produced by sexual reproduction, leave the host’s body in feces 200 µm Proglottids with reproductive structures Hooks Sucker Scolex

  24. Rotifera • Pseudocoelomates – body cavity between digestibe tract and body wall is not completely lined by mesoderm • Rotifers have an alimentary canal, a digestive tube with a separate mouth and anus (complete digestive tract) that lies within a fluid-filled pseudocoelom • http://www.youtube.com/watch?v=PALgTXQOqQo&feature=related (rotifer feeding)

  25. Fig. 33-13 Jaws Crown of cilia Anus Stomach 0.1 mm

  26. Nematoda: Roundworms • Nematodes, or roundworms, are found in most aquatic habitats, in the soil, in moist tissues of plants, and in body fluids and tissues of animals • Pseudocoelomates • They have an alimentary canal, but lack a circulatory system • Reproduction in nematodes is usually sexual, by internal fertilization • http://video.google.com/videoplay?docid=-2019570087567872766# (C. elegans crawling)

  27. Fig. 33-25 25 µm

  28. Conceptual Summary • Flatworms and roundworms have bilateral symmetry, the beginnings of cephalization, and three body layers with well developed tissues and organs. Phyla include many important parasites of humans.

  29. All of the animals that we cover from this point on are coelomates – body cavity (coelom) is completely lined by mesoderm. Groups are divided as protostomes or deuterostomes

  30. Mollusca • Phylum Mollusca includes snails and slugs, oysters and clams, and octopuses and squids • Basic body plan of muscular head-food, with body on top a loosely covered mantle which may secrete a shell • Gastropods have a well defined head, tentacles and elongated flattened foot • Marine and freshwater filter feeders have a body flattened between two valves of a hinged she. Bivalvia • Cephalopods are on the the most advanced invertebrate groups (octopus, squid, nautilus) • Protostomes

  31. Fig. 33-15 Nephridium Heart Visceral mass Coelom Intestine Gonads Mantle Stomach Mantle cavity Mouth Shell Radula Anus Gill Radula Mouth Nerve cords Esophagus Foot

  32. Fig. 33-16

  33. Fig. 33-17 (a) A land snail (b) A sea slug

  34. Fig. 33-19

  35. Fig. 33-20 Coelom Hinge area Mantle Gut Heart Adductor muscle Digestive gland Anus Mouth Excurrent siphon Shell Water flow Palp Foot Incurrent siphon Mantle cavity Gonad Gill

  36. Fig. 33-21 Octopus Squid Chambered nautilus

  37. http://www.youtube.com/watch?v=OBg0k9GbHiw&feature=fvwrel (squid inking)http://www.youtube.com/watch?v=QMFqV4SJLWg (nautilus)

  38. Annelida: Segmented Worms • Possess a coelom and closed circulatory system • Body segmented - septa • Protostomes

  39. Fig. 33-22 Cuticle Septum (partition between segments) Epidermis Coelom Circular muscle Metanephridium Longitudinal muscle Anus Dorsal vessel Chaetae Intestine Fused nerve cords Ventral vessel Nephrostome Metanephridium Clitellum Esophagus Crop Pharynx Giant Australian earthworm Intestine Gizzard Cerebral ganglia Mouth Ventral nerve cord with segmental ganglia Subpharyngeal ganglion Blood vessels

  40. Fig. 33-23 Parapodia

  41. Fig. 33-24

  42. Arthropoda: (jointed foot) • Major evolutionary advances over other invertebrate groups include exoskeleton (chitin) and jointed appendages • Open circulatory system in which fluid called hemolymph is circulated into the spaces surrounding the tissues and organs (fig. 42.3 pg. 900) • Main groups are arachnids (spiders, ticks), crustaceans (lobsters, crabs, shrimp, krill), and insects • Rotostomes

  43. Fig. 33-29 Cephalothorax Abdomen Antennae (sensory reception) Thorax Head Swimming appendages (one pair located under each abdominal segment) Walking legs Pincer (defense) Mouthparts (feeding)

  44. Fig. 33-30

  45. Fig. 33-31 50 µm Scorpion Dust mite Web-building spider

  46. Arachnids have an abdomen and a cephalothorax, which has six pairs of appendages, the most anterior of which are the chelicerae • Gas exchange in spiders occurs in respiratory organs called book lungs • Many spiders produce silk, a liquid protein, from specialized abdominal glands

  47. Fig. 33-32 Stomach Intestine Brain Heart Digestive gland Eyes Ovary Poison gland Book lung Anus Gonopore (exit for eggs) Pedipalp Chelicera Spinnerets Sperm receptacle Silk gland

  48. Fig. 33-33

  49. Fig. 33-34

  50. Fig. 33-35 Abdomen Thorax Head Compound eye Antennae Heart Cerebral ganglion Dorsal artery Crop Anus Vagina Malpighian tubules Ovary Tracheal tubes Mouthparts Nerve cords

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