Invertebrate Diversity I Porifera, Cnidaria, Ctenophora, Platyhelminthes, Rotifera, Nematoda

1. Invertebrate Diversity IPorifera, Cnidaria, Ctenophora, Platyhelminthes, Rotifera, Nematoda

2. Kingdom Animalia • Heterotrophic ingesters • Multicellular • “higher” groups have tissues • tissues arranged into organs in some groups • No cell walls – flexible • Nervous tissue & Muscle tissue • No alternation of generations • Common early embryological development

3. Parazoa: no symmetry no true tissues or organs 1 phylum: Porifera Eumetazoa: all symmetrical radial or bilateral almost all have tissues all other animal phyla (~35 phyla) 2 Sub-kingdoms in Animalia

4. 1 Tissue specialization Aggregates Diploblastic – 2 germ layers Triploblastic – 3 germ layers Bases for traditional invertebrate taxonomy Choanoflagellate Colony (Protist)

5. 2 Body symmetry Bases for traditional invertebrate taxonomy None Radial Bilateral

6. 3 Body Cavity Bases for traditional invertebrate taxonomy

7. 4 Early embryology Bases for traditional invertebrate taxonomy CleavageCoelom formationFate of blastopore spiral, determinate radial, indeterminate schizocoelous enterocoelous protostome deuterostome mouth anus

8. Two alternative family trees morphological, developmental Biochemical, molecular

9. Invertebrates “animals without backbones” 35.001 modern animal phyla origin of all modern phyla in Cambrian Explosion (~540mya) Vertebrates “animals with backbones” one diverse subphylum of Ph. Chordata staggered evolution of vertebrate classes Vertebrates vs. Invertebrates

10. Q1: Which of the following is NOT a common feature of the eumetazoan animals • cell walls • multicellular • heterotrophic • tissues

11. Q2: Which of the following is NOT a basis for traditional animal taxonomy • tissue specialization/number of germ layers • body symmetry • molecular similarities • early embryology

12. Ph. Porifera: the sponges

13. Anatomy of a Sponge

15. Spicules

16. Classes of Poriferans • Calcarea – small, calcium spicules • Demospongae – larger, silica spicules – the includes the bath sponges and flower baskets • Hexactinellidae – hexagonal spicule array – the “glass sponges”

17. Some poriferans . . .

18. Ph. Cnidariaformerly Colenterata (bag animals) • true tissues - diploblastic (2 layers) • no organs • radially symmetric • gastrovascular cavity with single opening • cnidocytes, nematocysts, and tentacles • 2 main body forms: polyp & medusa Polyp -sessile, asexual Medusa - motile, sexual

19. Cnidocytes: stinging cells

20. Classes of Cnidarians: • Cl. Hydrozoa: hydroids (dominant polyp stage) • Cl. Scyphozoa: true jellyfish (dominant medusa stage) • Cl. Anthozoa: sea anemones, corals (no medusa stage)

21. Class Hydrozoa • The polypoid body form dominates • Hydra • Portuguese man o’ war

22. Man o’ warA colonial hydroid!

23. Cl Scyphozoa: jellyfish

24. Cl Anthozoa -- anemone

25. Class Anthozoa: Coral

26. Coral Polyps

27. Ph. Ctenophora: comb jellies • 8 rows of ciliary plates • digestive tube – 2 openings • colloblasts (adhesive structures on tentacles)

28. Comb jelly Retractable tentacles!

29. Ctenophore

30. Comb Jelly (“Sea gooseberry”)

31. Q3: Phylum Cnidaria is named for the characteristic • bag-like structure • medusa and polyp life stages • two germ layers • stinging cells

32. Q4: True jellyfish belong to the class • Hydrozoa • Scyphozoa • Anthozoa • Ctenophora

33. Ph. Platyhelminthes: flatworms • Bilaterally symmetric • 3 tissue layers; organs • no body cavity: are acoelomates • dorsoventrally flattened (thus the name . . . ) • primitive cephalization (but not in Class Cestoidea) • blind-ended gut (also not in Cl. Cestoidea) • hermaphroditic (mostly)

34. 4 classes of flatworms: • Cl .Turbellaria: free-living flatworms, e.g., Planaria • Cls. Trematoda & Monogenea: flukes • Cl. Cestoidea: tapeworms

35. Planaria

37. Class Trematoda: flukes(digenetic – intermediate and definitive hosts)

38. Life Cycle of the Blood Fluke(Schistosoma)

39. Political Cycle of the Blood Fluke(Schistosoma mansoni) & (or, what do politicians and parasites have in common?)

40. Class Cestoidea: tapeworms Tapeworm encysted in muscle

41. Q5: Cestodes (tapeworms) differ from the other flatworms in that they • lack digestive organs • lack a cephalized nervous system • have a segmented body plan • all of the above

42. Ph. Rotifera: the rotifers • Pseudocoelomates • Mostly freshwater, but also on moss, lichens • very small! But have complete digestive tract • have a “crown of cilia” that draws food in toward their jaws

43. Rotifers

44. Rotifer

45. Ph. Acanthocephala – spiny-headed worms: • barbed proboscis • rudimentary gut • intestinal parasites • genomics suggests they are giant, modified rotifers

46. Ph. Nematoda: • Unsegmented roundworms • pseudocoelomates • hydrostatic skeleton • many are animal parasites, e.g., pinworms, hook worms, Trichinella, Ascaris • many are plant parasites

47. Nematode

48. Trichinella

49. Filariasis (Elephantiasis) Microfilarial nematodes Transfer via mosquitoes Adults live in blood stream & large lymphatic vessels Larvae infest peripheral lymphatic capillaries - crepuscular Body’s reaction is overgrowth of connective tissue

50. Q6: Pseudocoelomate phyla include the • Protista and Porifera • Cnidaria and Ctenophora • Platyhelminthyes and Chordata • Rotifera and Nematoda