Ochre sea stars, Pisaster ochraceus

1. Ochre sea stars, Pisaster ochraceus Chapter 33 Introduction to Invertebrates

2. One view of animal diversity based on body-plan grades

3. 33.1 Sponges are basal animals that lack true tissues 33.2 Cnidarians are an ancient phylum of eumetazoans 33.3 Lophotrochozoans have the widest range of animal body forms (flatworms, rotifers, lophophorates, molluscs, annelids) 33.4. Ecdysozoans is the most species-rich group (nematodes, arthropods) 33.5 Echinoderms and chordates are deuterostomes Chapter 33 Outline (five concepts) Discovery Channel Video

4. Sponges – Porifera (Calcarea and Silicea)

5. 33.4 Anatomy of a sponge Reproduction = hermaphroditic Sponge spicules

6. 33.7 Cnidarians: Hydrozoans (top left), jelly (top right), sea anemone (bottom left), coral polyps (bottom right)

7. 33.5 Polyp and medusa forms of cnidarians

8. 33.6 A cnidocyte of a hydra http://www.youtube.com/watch?v=TWJat3byA8Y

9. 33.8 The life cycle of the hydrozoan Obelia

10. 33.8 The life cycle of the hydrozoan Obelia

11. 33.8 The life cycle of the hydrozoan Obelia

13. 33.1 Sponges are basal animals that lack true tissues 33.2 Cnidarians are an ancient phylum of eumetazoans 33.3 Lophotrochozoans have the widest range of animal body forms (flatworms, rotifers, lophophorates, molluscs, annelids) 33.4. Ecdysozoans is the most species-rich group (nematodes, arthropods) 33.5 Echinoderms and chordates are deuterostomes Chapter 33 Outline

14. 33.8 A ctenophore, or comb jelly One-way digestive tract No nematocysts

15. Platyhelminthes: A marine flatworm (class Turbellaria)

16. 33.10 Anatomy of a planarian

18. 33.12 Anatomy of a tapeworm

19. 33.11The life history of a blood fluke, Schistosoma mansoni (Trematoda)

20. Total persons infected (global): 200 million • Total persons infected (Africa): 170 million (second most prevalent parasitic disease in Africa) • Persons with associated morbidity: 120 million • Mortality Unknown, but 20 million severely infected

21. it emphasizes the beneficial relationship between humans and their environment. although these parasites are of little importance in modern society, they must be studied before they are completely eliminated. flatworms may secrete important chemicals for human use. it helps us to understand the evolutionary relationships between the different parasites. it may be possible to find a portion of that life cycle where the parasite is vulnerable and can be controlled. A feature of many members of the phylum of the Platyhelminthes (flatworms) is their complex life cycle. Understanding the life cycles of flatworm parasites is of great importance to human health because:

22. 33.1 Sponges are basal animals that lack true tissues 33.2 Cnidarians are an ancient phylum of eumetazoans 33.3 Lophotrochozoans have the widest range of animal body forms (flatworms, rotifers, lophophorates, molluscs, annelids) 33.4. Ecdysozoans is the most species-rich group (nematodes, arthropods) 33.5 Echinoderms and chordates are deuterostomes Chapter 33 Outline

23. 33.13 Rotifers (pseudo-coelomates) Reproduction by pathenogenesis

24. 33.1 Sponges are basal animals that lack true tissues 33.2 Cnidarians are an ancient phylum of eumetazoans 33.3 Lophotrochozoans have the widest range of animal body forms (flatworms, rotifers, lophophorates, molluscs, annelids) 33.4. Ecdysozoans is the most species-rich group (nematodes, arthropods) 33.5 Echinoderms and chordates are deuterostomes Chapter 33 Outline

25. 33.14 Lophophorates: Bryozoan (left aka Ectoprocts), Phonorids (middle), and Brachiopod (right) – all coelomates

26. Bryozoans: Colonial animals that superficially resemble mosses

27. Nemertea – proboscis worms (pseudoceolomates)

28. 33.1 Sponges are basal animals that lack true tissues 33.2 Cnidarians are an ancient phylum of eumetazoans 33.3 Lophotrochozoans have the widest range of animal body forms (flatworms, rotifers, lophophorates, molluscs, annelids) 33.4. Ecdysozoans is the most species-rich group (nematodes, arthropods) 33.5 Echinoderms and chordates are deuterostomes Chapter 33 Outline

30. Gastropods: Nudibranchs (‘sea slug’, top left and top right), terrestrial snail (bottom left), deer cowrie (bottom right)

31. 33.15 Basic body plan of mollusks

33. 33.16 A chiton

34. 33.18. The result of torsion in a gastropod (twisting of the visceral mass during embryonic development resulting in the anus being near the anterior mouth).

35. 33.20 Anatomy of a clam

36. Dreissena polymorpha Zebra mussel

38. 33.1 Sponges are basal animals that lack true tissues 33.2 Cnidarians are an ancient phylum of eumetazoans 33.3 Lophotrochozoans have the widest range of animal body forms (flatworms, rotifers, lophophorates, molluscs, annelids) 33.4. Ecdysozoans is the most species-rich group (nematodes, arthropods) 33.5 Echinoderms and chordates are deuterostomes Chapter 33 Outline

40. See also 33.21. Cephalopods: Squid (top left and bottom left), nautilus (top right), octopus (bottom right)

41. 33.1 Sponges are basal animals that lack true tissues 33.2 Cnidarians are an ancient phylum of eumetazoans 33.3 Lophotrochozoans have the widest range of animal body forms (flatworms, rotifers, lophophorates, molluscs, annelids) 33.4. Ecdysozoans is the most species-rich group (nematodes, arthropods) 33.5 Echinoderms and chordates are deuterostomes Chapter 33 Outline

42. Annelida: External anatomy of an earthworm (note segmentation) http://www.youtube.com/watch?v=0Texxu3p7I8&feature=related Tubifex sp. Lumbricus sp.

43. 33.24. Anatomy of an earthworm

45. Annelids, the segmented worms: Polychaete (left), feather-duster worm (middle); Hirudinea (leech, right)

46. 33.1 Sponges are basal animals that lack true tissues 33.2 Cnidarians are an ancient phylum of eumetazoans 33.3 Lophotrochozoans have the widest range of animal body forms (flatworms, rotifers, lophophorates, molluscs, annelids) 33.4. Ecdysozoans is the most species-rich group (nematodes, arthropods) 33.5 Echinoderms and chordates are deuterostomes Chapter 33 Outline

47. 33.26 Free-living nematode Vinegar eel

48. Two American ‘Worm People’ Win Nobel for RNA Work This year’s Nobel Prize in Physiology or Medicine has been awarded to two American researchers, Andrew Z. Fire and Craig C. Mello, for a far-reaching discovery about how genes are controlled within living cells. The finding by Drs. Fire and Mello made sense of a series of puzzling results obtained mostly by plant biologists, including some who were trying to change the color of petunias. By clarifying what was happening, they discovered an unexpected system of gene regulation in living cells and began an explosive phase of research in a field known variously as RNA interference or gene silencing. This natural method of switching genes off has turned out to be a superb research tool, allowing scientists to understand the role of new genes by suppressing them. The method may also lead to a new class of drugs that switch off unwanted processes in disease. Two gene-silencing drugs designed to treat macular degeneration are already in clinical trials. Dr. Fire, now at Stanford University, worked at the Carnegie Institution of Washington when he made the discovery. Dr. Mello, a frequent collaborator, is at the University of Massachusetts Medical School in Worcester. Both are “worm people,” as scientists who do their biology in the roundworm Caenorhabditis elegans call themselves. Prior to their discovery, plant biologists over many decades had found odd exceptions to Mendel’s laws of heredity, including some unexplained effects produced by injecting RNA, the less-well-known cousin of DNA, into plants. Both are chemicals called nucleic acids, but DNA is longer and more stable and is used by the cell for the archival function of storing genetic information. RNA is shorter and more active, and performs many of the cell’s more difficult tasks, like making copies of the genes in DNA and directing the synthesis of the proteins specified by the genes………………

49. 33.27 Parasite nematode, Trichinella spiralis in human muscle tissue Trichinosis: may be contracted from undercooked meat – fever diarrhea, swelling, rarely fatal

50. 33.1 Sponges are basal animals that lack true tissues 33.2 Cnidarians are an ancient phylum of eumetazoans 33.3 Lophotrochozoans have the widest range of animal body forms (flatworms, rotifers, lophophorates, molluscs, annelids) 33.4. Ecdysozoans is the most species-rich group (nematodes, arthropods) 33.5 Echinoderms and chordates are deuterostomes Chapter 33 Outline