1. BASAL METAZOANS

2. Bauplan (pl. Baupläne) The generalized body plan of an archetypal member of a major taxon. 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"

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

4. PLACOZOA

5. Distribution

6. PLACOZOA 1) Asymmetric. 2) No distinct tissues or organs. 3) No nervous system. 4) No body cavity or digestive cavity. 5) Body is shaped like a flat disc. 6) Two layers of single cells. 7) Marine. 8) One species only known Trichoplax adhaerens Characteristics of Placozoa

7. PLACOZOA Cover cells Cylinder cells Gland cells Fibre cells

8. PLACOZOA Placozoan movement Feeding -

9. PLACOZOA Reproduction 1. Binary fission 2. Budding 3. Sexual

10. PLACOZOA Reproduction 1. Binary fission 2. Budding 3. Sexual “hollow swarmer”

11. PLACOZOA Reproduction 1. Binary fission 2. Budding 3. Sexual “hollow swarmer”

12. PLACOZOA Reproduction 1. Binary fission 2. Budding 3. Sexual

13. PLACOZOA Reproduction 1. Binary fission 2. Budding 3. Sexual oocyte yolk zygote Fertilization membrane

14. CNIDARIA ANTHOZOA CUBOZOA HYDROZOA SCYPHOZOA

15. Diploblasty Gastroderm Ectoderm Mesoglea

16. CNIDARIA Feeding

17. CNIDARIA - EMBRYOLOGY Stereogastrula Radial and holoblastic cleavage

18. CNIDARIA – PLANULA LARVA Ectoderm Endoderm

19. CTENOPHORA – COMB JELLIES

20. CTENOPHORA – BIRADIAL SYMMETRY

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

22. Muscle fibres CTENOPHORA TENTACLE

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

24. CTENOPHORA FEEDING - COLLOBLASTS

25. CTENOPHORE - STATOLITHS - Balancing organ Statocyst

26. CTENOPHORA – REPRODUCTION AND DEVELOPMENT

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

28. Cleavage in PleurobranchiaCleavage in Beroe

29. CTENOPHORA LARVAE

30. COMPARISON OF CNIDARIA AND CTENOPHORE CNIDARIACTENOPHORA Diploblastic with acellular mesoglea Diploblastic (triploblastic?) with cellular mesenchyme Radial symmetryBiradial symmetry ; oral/aboral axes NematocystsColloblasts Gastrovascular body cavity Nerve netMore specialized nerve net Musculature – extensions of epithelial cellsMusculature – from mesenchyme cells Alternation of generationsNo alternation of generations Planula larvaCydippid larva

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

32. 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

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

34. TRIPLOBLASTY EctodermMesodermEndoderm

35. TURBELLARIA – MAJOR ORGAN SYSTEMS