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Chapter 29

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Chapter 29

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  1. Chapter 29 The Animal Kingdom The Protostomes Invertebrates Video

  2. Coelom • Fluid-filled space lined w/mesoderm; between digestive tube and outer body wall • Tube-within-a-tube plan • Inner tube no longer attached to body wall

  3. Advantages of Coelom • Can serve as hydrostatic skeleton (fluid under pressure) • Contracting muscles push against tube of fluid • Greater range of movement • Swim, crawl, walk • Space, cushion for internal organs, gonads • Transport of food, O2, waste

  4. Phylum Nemertea • Ribbon worms, proboscis worms • Proboscis = long, hollow muscular tube • Can be everted from anterior end of body • Wrap around prey • Sharp, sticky or toxic • Functionally acoelomate (chamber around proboscis is true coelomic space = rhynchocoel) • Circulatory system – blood vessels, no heart

  5. Fig. 33-3l A ribbon worm

  6. Phylum MolluscaClams, oysters, octopods, snails, slugs, giant squid • Basic characteristics • Soft body – usually covered by shell • Foot – locomotion • Visceral mass – above foot • Mantle – cover visceral mass • Radula – rasplike, belt of teeth • Coelom – reduced, small around certain organs • Hemocoel - blood

  7. 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

  8. Phylum Mollusca • Digestive • Mouth, buccal cavity, esophagus, stomach, intestine, anus • Radula in buccal cavity • Circulatory – open (most) • Blood = hemolymph – bathes tissues • Heart – aorta – blood vessels – sinuses (make up hemocoel) – blood vessels – gills – heart • Closed system – active squid, octopods • Blood in blood vessels completely

  9. Phylum Mollusca • Excretory • Metanephridia – funnels waste from fluid in coelom to excretory pore

  10. 4 Classes of Mollusks • 1. Polyplacophora – “many plates” • Chitons • Shell of 8 dorsal plates, head reduced, no eyes or tentacles • 2. Gastropoda • Well-developed head w/tentacles, 2 simple eyes, foot • Torsion – twist visceral mass; allows head to enter shell 1st before foot • Snails – single, spiral coiled shell • Limpets – shells like flat dunce cap • Nudibranchs (sea slug) – no shell

  11. Fig. 33-16

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

  13. Fig. 33-18 Intestine Mantle cavity Stomach Anus Mouth

  14. Nudibranch (Sea slug)

  15. 3. Bivalvia • Clams, oysters, mussels, scallops • 2 part shell • Nervous – 3 pair ganglia, 2 pair nerve cords • Eyespots • Suspension feeders – water in through siphon (no radula)

  16. Fig. 33-19

  17. 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

  18. 4. Cephalopoda – “head foot” • Swim fast, predators • Mouth w/tentacles (suckers to seize prey) • Radula + 2 beaks • Mantle has siphon • Jet propulsion • Head – well-developed eyes • Octopus – no shell • Squid – reduced shell inside body • Nautilus – coiled shell • Defense • Chromatophores – change color • Ink sac – black liquid

  19. Fig. 33-21 Octopus Squid Chambered nautilus

  20. Phylum Annelida – “ringed” • Segmented worms • Facilitates locomotion • Coelom divided – each segment own muscles • Setae – bristle-like structures - traction • Bilateral symmetry • Tubular body • Nervous • Simple brain (paired ganglia) + ventral nerve cord • Each seg. = pair ganglia + lateral nerves

  21. Phylum Annelida • Closed circulatory system • Complete digestive tract • Mouth - anus • Respiration • cutaneous • Excretion • Pair metanephridia in each segment

  22. Class Polychaeta – “many bristles” • Marine • Parapodia – pair of paddle-shaped appendages on each body segment • Locomotion, gas exchange, bear setae • Head w/eyes and antennae • Optional – tentacles, palps • Separate sexes • Gametes in water same time (lunar, tides)

  23. Fig. 33-23 Parapodia

  24. Tubeworms - Polychaetes

  25. Class Oligochaeta – few bristles • Fresh water/terrestrial • No parapodia, few bristles • Lack well-developed head • Hermaphrodites

  26. Class Oligochaeta - Lumbricus terrestris • Cuticle • Mucus layer • Muscles in body wall • Relationship with soil • Complex digestive system • Pharynx – esophagus – crop (store) – gizzard (grind) – intestine (digest, absorb) – anus • Circulatory system – closed • Dorsal and ventral BV; BV in segments • 5 pair BV by esophagus

  27. Earthworm Locomotion

  28. Class Oligochaeta - Lumbricus terrestris • Gas exchange • Moist skin • Excretion • Paired metanephridia – almost every segment • Nervous • Simple brain (pair cerebral ganglia above pharynx and subpharyngeal ganglia below pharynx) • Ventral nerve cord • Pair fused ganglia – each segment – coordinate muscles

  29. Class Oligochaeta - Lumbricus terrestris • Reproduction • Hermaphroditic • 2 worms exchange sperms • Clitellum - ring of epidermis, secretion

  30. 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

  31. Class Hirudinea - leeches • Blood-sucking parasites (some nonparasitic) • Suck out blood and store in digestive tract • Hirudin – anticoagulant – from crop; ensures full meal • No setae or parapodia • Muscular suckers both body ends

  32. Fig. 33-24

  33. Lophophorate phyla • Ring of tentacles around mouth for capturing particles in water

  34. Fig. 33-14 Lophophore Lophophore (a) Ectoproct (sea mat) (b) Brachiopods

  35. Phylum Rotifera • “wheel animals” • Crown of cilia on anterior end • Beat rapidly – swim / feed

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

  37. Phylum Nematoda - roundworms • Decomposition, nutrient recyclers • Free-living; parasites • Body – point both ends, cuticle • Epidermis unusual – no composed of distinct cells • Pseudocoelom – fluid – muscle contraction, nutrient distribution • Bilateral symmetry

  38. Fig. 33-25 25 µm

  39. Phylum Nematoda • Complete digestive system – 3 tissue layers • Lack specific circulatory parts • Sexes usually separate • No well-define head

  40. Crawling Nematode

  41. Examples of Nematodes • Ascaris – intestinal human parasite • Eggs in feces • Poor sanitation – eggs  soil (fertilizer) • Ingest eggs on unwashed fruit/veg. OR hands • Hookworm – lining human intestine, suck blood • Eggs – feces – host barefoot – larvae into skin / blood • Trichina – small intestine mammals • Undercooked, infected meat • Encyst in skeletal muscle; cysts calcify • Pinworm - large intestine, kids • Eggs ingested – dirty hands • Female worms – anal region – deposit eggs - itching

  42. Fig. 33-26 Muscle tissue Encysted juveniles 50 µm

  43. Phylum Arthropoda - “jointed foot” – very successful • Segmented body – specialization • Exoskeleton – chitin + protein • Protection, water loss, molting (disadvantage) • Paired, jointed appendages • Swim, walk, get prey, sensory, reproduction • Nervous system – sense organs • Antennae, eyes, ganglia • Open circulatory system - hemocoel

  44. Phylum Arthropoda • Gas exchange • Water – gills • Land – tracheal tubes, book lungs

  45. Onychophorans - “missing link” between annelids and arthropods; “velvet worms” • Like Annelids • Internal segments • Like Arthropods • Open circulation • Tracheal tubes • Unbranched legs • Jaws from appendages

  46. 3 Subphyla of Arthropods:Subphylum Chelicerata • Horseshoe crabs, arachnids • No antennae • Chelicerae (1st pair) – fanglike feeding appendages • Body = cephalothorax + abdomen • Pedipalps (2nd pair) = locomotion, food, defense or copulation • 4 pair legs on cephalothorax - walking

  47. Fig. 33-3r An onychophoran

  48. Subphylum Chelicerata – Horseshoe Crabs • Living fossil • Tail for locomotion • 5 pair walking legs