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General Body Plan

General Body Plan. Diploblastic epidermis gastrodermis Tissue Radially symmetrical Cnidocytes. General Body Plan. Dimorphism: 2 different body forms are usually present in the life cycle:. aboral. oral. aboral. oral. 3 Classes. Hydrozoa: polyp dominant Scyphozoa: medussa dominant

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General Body Plan

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  1. General Body Plan • Diploblastic • epidermis • gastrodermis • Tissue • Radially symmetrical • Cnidocytes

  2. General Body Plan Dimorphism: 2 different body forms are usually present in the life cycle: aboral oral aboral oral

  3. 3 Classes • Hydrozoa: polyp dominant • Scyphozoa: medussa dominant • Anthozoa: no medussa

  4. The Acoelomates • Trploblastic animals without a coelom

  5. Acoelomate Characteristics: Triploblastic 3 Tissue Layers gastrodermis mesoderm/ mesenchyme epidermis 3 Embryonic Germ Layers endoderm mesoderm ectoderm

  6. zygote blastocoel archenteron blastopore ectoderm endooderm mesoderm

  7. Acoelomate Characteristics: Triploblastic Gut Mesoderm Ectoderm Endoderm

  8. Acoelomate Characteristics: No coelom What is a coelom? A body cavity that is completely surrounded by mesodermal tissue. A coelom is not open to the outside of the animal.

  9. What is a coelom?

  10. Acoelomate Characteristics: No coelom gut gut endoderm endoderm gut

  11. Acoleomate Characteristics:Level of Organization Organ • Tissues are organized into organs • mesodermal tissue gives rise to many organs

  12. Acoleomate Characteristics:Body Plan Bilateral Symmetry Anterior: toward the front of the body Posterior: toward the rear of the body

  13. Acoleomate Characteristics:Body Plan left anterior dorsal right posterior ventral

  14. Body Plan Cephalization: the concentration of sensory organs in the head of the animal Eye spots: photosensitive organs Auricles: chemoseneory organs

  15. Acoelomate Phyla 1. Gnathostomulida 2. Platyhelminthes 3. Nemaertea

  16. Phylum Platyhelminthes the flatworms

  17. Phylum Platyhelminthes: • Mostly aquatic, although there are a few terrestrial species. • Most are small (a few mm), but some can grow to be sever meters long. • Many are endoparasites of vertebrates.

  18. Feeding and Digestion Feeding • Free-living, carnivorous Many predatory forms have a pharynx that is used to capture prey

  19. Feeding and Digestion Pharynx: the pharynx is an extension of the gut that can be extruded though the mouth.

  20. Feeding and Digestion Feeding • parasitic Parasitic forms often have modified feeding structures (e.g. the anterior end of a tapeworm) hooks suckers

  21. Feeding and Digestion Digestion • incomplete digestive system mouth gut: saclike pharynx pharyngeal opening

  22. Feeding and Digestion Digestion • many forms have a branched gut The trilobed gut of a planarian.

  23. Feeding and Digestion Digestion • the digestive system is reduced (or absent) in many parasitic forms

  24. Feeding and Digestion intestine Taenia pisiformis intestinal parasite NO DIGESTIVE SYSTEM ! Bdelloura candida Free-living:branched gut Grylodactylus liver fluke: relatively unbranched gut

  25. Feeding and Digestion Digestion • extracellular (in the intestine) • proteolytic enzymes released by gastroodermal tissues • intracellular • phagocytosis by gastrodermal cells

  26. Osmoregulation and Excretion Osmoregulation: the maintenance of salt/water balance • Protonephridia and flame cells

  27. Osmoregulation and Excretion Protonephridia Protonephridia: a system of tubules used to collect fluid and transport it to the outside of the body

  28. Osmoregulation and Excretion The beating of the flame cell cilia creates negative pressure which pulls fluid out of the body protonephridia flame cell

  29. Osmoregulation and Excretion Excretion • Diffusion of waste

  30. Nervous System The Cnidarian nerve net: receptor neuron

  31. Nervous System Platyhelminthes have a more complex nervous system Cerebral ganglia Lateral nerve cords Transverse nerves

  32. Nervous System pigment cup retinular cells light sensitive region

  33. Support and Locomotion Skeletal System • No skeletal system

  34. Locomotion Many small flatworms crawl on “slime trails” using cilia.

  35. Locomotion cilia on the dorsal epidermis rhabdites: produce mucus

  36. Locomotion Large species use circular and longitudinal muscles to swim.

  37. Locomotion circular muscles longitudinal muscles

  38. Reproduction Asexual: fission many flatworms are capable of reproducing asexually by constricting their bodies and separating into two individuals

  39. Reproduction Asexual Periods of asexual reproduction are common in many parasites.

  40. Reproduction Sexual • usually monoecious, but most must cross fertilize • Internal fertilization (usually reciprocal sperm transfer)

  41. Phylum Platyhelminthes Class Turbellaria Class Trematoda Class Cestoda parasitic

  42. Class Turbellaria Free-living flatworms

  43. Body Plan cerebral ganglion eye spot anterior branch of intestine ovaries nerve cords pharynx testes posterior branches of intestine

  44. Digestive System pharynx

  45. Digestive System triclad polyclad

  46. Reproduction Asexual: fission many flatworms are capable of reproducing asexually by constricting their bodies and separating into two individuals

  47. Reproduction Sexual • Internal fertilization • Simple life cycle

  48. Phylum Platyhelminthes Class Turbellaria Class Trematoda Class Cestoda parasitic

  49. Adaptations for Parasitism Increased reproductive potential The presence of adhesion organs Poorly developed sensory systems Reduced or absent digestive system Resistant cuticle Complex life cycles

  50. Class Trematoda Parasitic Flukes Endoparasites of many animals

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