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BASAL METAZOANS

BASAL METAZOANS. A body plan, baupläne , ground plan, ground pattern , or bodyplan , is "an assemblage of morphological features shared among many members of a phylum-level group". Bauplan (pl. Baupläne ) The generalized body plan of an archetypal member of a major taxon. Look at 4 groups.

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BASAL METAZOANS

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  1. BASAL METAZOANS

  2. A body plan, baupläne, ground plan, ground pattern, or bodyplan, is "an assemblage of morphological features shared among many members of a phylum-level group" Bauplan (pl. Baupläne) The generalized body plan of an archetypal member of a major taxon.

  3. Look at 4 groups 1. Placozoa 2. Cnidaria 3. Ctenophora 4. Platyhelminthes

  4. PLACOZOA

  5. PLACOZOA

  6. CNIDARIA ANTHOZOA HYDROZOA SCYPHOZOA CUBOZOA

  7. Diploblasty Ectoderm Mesoglea Gastroderm

  8. CNIDARIA Feeding

  9. CNIDARIA - EMBRYOLOGY Radial and holoblastic cleavage Stereogastrula

  10. CNIDARIA – PLANULA LARVA Ectoderm Endoderm

  11. CTENOPHORA – COMB JELLIES

  12. CTENOPHORA – BIRADIAL SYMMETRY

  13. CTENOPHORA Statocyst Anal pore Tentacle Stomadeum Tentacle sheath Meridional canal Pharynx Mouth

  14. Statocyst

  15. CTENOPHORA TENTACLE Muscle fibres

  16. CTENOPHORA – SUPPORT & LOCOMOTION Support - elastic mesenchyme Ctenophora video

  17. CTENOPHORA – SUPPORT & LOCOMOTION Locomotion - Comb rows Ctenophora video

  18. CTENOPHORA FEEDING - COLLOBLASTS

  19. CTENOPHORE - STATOLITHS - Balancing organ

  20. CTENOPHORA – REPRODUCTION AND DEVELOPMENT

  21. CTENOPHORA – REPRODUCTION AND DEVELOPMENT 1. Form blastomeres – meridional cleavage 5. Macromeres invaginate (gastrulation) -micromeres become ectoderm -macromeres become endoderm 2. Third division – 8 macromeres 3. Fourth division – latitudinal and unequal - micromeres 6. Just before gastrulation – - Produce additional micromeres on oral side – invaginate to form stomatodeum 4. Micromeres divide and spread over aboral pole and macromeres

  22. Cleavage in Beroe Cleavage in Pleurobranchia

  23. CTENOPHORA LARVAE

  24. COMPARISON OF CNIDARIA AND CTENOPHORE CNIDARIA CTENOPHORA Diploblastic with acellularmesoglea Diploblastic (triploblastic?) with cellular mesenchyme Radial symmetry Biradial symmetry ; oral/aboral axes Nematocysts Colloblasts Gastrovascular body cavity Gastrovascular body cavity Nerve net More specialized nerve net Musculature – extensions of epithelial cells Musculature – from mesenchyme cells Alternation of generations No alternation of generations Planula larva Cydippid larva

  25. PLATYHELMINTHES Who are they? Turbellaria (flatworms) Trematoda (flukes) Monogenea (flukes) Cestoda (tapeworms

  26. PLATYHELMINTHES Common trends 1. Triploblastic acoelomates 2. Cephalization and central nervous system 3. Mesoderm – fibrous and muscular mesenchyme 4. Osmoregulatory structure - protonephridia 5. Elaborate reproductive systems

  27. PLATYHELMINTHES Limiting factors l. Lack of efficient circulatory system 2. Lack of gas exchange system

  28. TRIPLOBLASTY Ectoderm Mesoderm Endoderm

  29. TURBELLARIA – MAJOR ORGAN SYSTEMS

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