1. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings PowerPoint ® Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp Chapter 33 Invertebrates

2. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Overview: Life Without a Backbone Invertebrates are animals that lack a backbone They account for 95% of known animal species

3. Fig. 33-2 ANCESTRAL PROTIST Common ancestor of all animals Calcarea and Silicea Eumetazoa Bilateria Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia

4. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Concept 33.1: Porifera: Sponges are basal animals that lack true tissues Sponges are sedentary animals from the phyla Calcarea and Silicea (Porifera) They live in both fresh and marine waters Sponges lack true tissues and organs

5. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Sponges are suspension feeders Choanocytes, flagellated collar cells, generate a water current through the sponge and ingest suspended food Water is drawn through pores into a cavity called the spongocoel, and out through an opening called the osculum Concept 33.1: Porifera: Sponges are basal animals that lack true tissues

6. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Sponges consist of a noncellular mesohyl layer between two cell layers Amoebocytes are found in the mesohyl and play roles in digestion and structure Most sponges are hermaphrodites: Each individual functions as both male and female Concept 33.1: Porifera: Sponges are basal animals that lack true tissues

7. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 33-4 Azure vase sponge (Callyspongia plicifera) Spongocoel Osculum Pore Epidermis Water flow Mesohyl Choanocyte Flagellum Collar Food particles in mucus Choanocyte Amoebocyte Phagocytosis of food particles Spicules Amoebocytes

8. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 33-2 ANCESTRAL PROTIST Common ancestor of all animals Calcarea and Silicea Eumetazoa Bilateria Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia

9. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Concept 33.2: Cnidarians are an ancient phylum of eumetazoans All animals except sponges and a few other groups belong to the clade Eumetazoa, animals with true tissues Phylum Cnidaria is one of the oldest groups in this clade

10. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Cnidarians have diversified into a wide range of both sessile and motile forms including jellies, corals, and hydras They exhibit a relatively simple diploblastic, radial body plan Concept 33.2: Cnidarians are an ancient phylum of eumetazoans

11. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings A sac with a central digestive compartment, the gastrovascular cavity (GVC) A single opening functions as mouth and anus There are two variations on the body plan: the sessile polyp and motile medusa Concept 33.2: Cnidarians are an ancient phylum of eumetazoans

12. Fig. 33-5 Polyp Mouth/anus Body stalk Tentacle Gastrovascular cavity Gastrodermis Mesoglea Epidermis Tentacle Mouth/anus Medusa

13. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Cnidarians are carnivores that use tentacles to capture prey The tentacles are armed with cnidocytes, unique cells that function in defense and capture of prey Nematocysts are specialized organelles within cnidocytes that eject a stinging thread Concept 33.2: Cnidarians are an ancient phylum of eumetazoans

14. Fig. 33-6 Tentacle Nematocyst “Trigger” Cuticle of prey Thread discharges Thread (coiled) Cnidocyte Thread

15. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Phylum Cnidaria is divided into four major classes: Table 33.1 – Hydrozoa – Scyphozoa – Cubozoa – Anthozoa Concept 33.2: Cnidarians are an ancient phylum of eumetazoans

16. Table 33-1

17. Fig. 33-7 (a) Colonial polyps (class Hydrozoa) (b) Jellies (class Scyphozoa) Sea wasp (class Cubozoa) (d) Sea anemone (class Anthozoa) (c)

18. Fig. 33-8-3 Feeding polyp Reproductive polyp Medusa bud Medusa ASEXUAL REPRODUCTION (BUDDING) Portion of a colony of polyps 1 mm Key Haploid (n) Diploid (2n) Gonad SEXUAL REPRODUCTION MEIOSIS FERTILIZATION Egg Sperm Zygote Planula (larva) Developing polyp Mature polyp

19. Fig. 33-2 ANCESTRAL PROTIST Common ancestor of all animals Calcarea and Silicea Eumetazoa Bilateria Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia

20. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Concept 33.3: Lophotrochozoans, a clade identified by molecular data, have the widest range of animal body forms Bilaterian animals have bilateral symmetry and triploblastic development The clade Bilateria contains Lophotrochozoa, Ecdysozoa, and Deuterostomia

21. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The clade Lophotrochozoa was identified by molecular data – Some develop a lophophore for feeding, others pass through a trochophore larval stage, and a few have neither feature – Lophotrochozoa includes the flatworms, molluscs, and annelids Concept 33.3: Lophotrochozoans, a clade identified by molecular data, have the widest range of animal body forms

22. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Phylum Platyhelminthes: Flatworms Members of phylum Platyhelminthes live in marine, freshwater, and damp terrestrial habitats Triploblastic development and acoelomates They are flattened dorsoventrally and have a gastrovascular cavity (GVC) Gas exchange takes place across the surface, and protonephridia regulate the osmotic balance

23. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Flatworms are divided into four classes: Table 33.2 – Turbellaria (mostly free-living flatworms) – Monogenea (monogeneans) – Trematoda (trematodes, or flukes) – Cestoda (tapeworms) Phylum Platyhelminthes: Flatworms

24. Table 33-2

25. Fig. 33-9

26. Fig. 33-10 Pharynx Gastrovascular cavity Mouth Eyespots Ganglia Ventral nerve cords

27. Fig. 33-11 Human host Motile larva Snail host Ciliated larva Male Female 1 mm

28. Fig. 33-12 Proglottids with reproductive structures Hooks Sucker Scolex 200 µm

29. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Phylum Mollusca Phylum Mollusca includes snails and slugs, oysters and clams, and octopuses and squids Most molluscs are marine, though some inhabit fresh water and some are terrestrial Molluscs are soft-bodied animals, but most are protected by a hard shell

30. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Body plan with three main parts: – Muscular foot – Visceral mass – Mantle Many molluscs also have a water-filled mantle cavity, and feed using a rasplike radula Phylum Mollusca

31. Fig. 33-15 Nephridium Visceral mass Coelom Mantle cavity Heart Intestine Gonads Stomach Shell Radula Mouth Esophagus Nerve cords Foot Gill Anus Mouth Radula

32. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Most molluscs have separate sexes with gonads located in the visceral mass The life cycle of many molluscs includes a ciliated larval stage called a trochophore Phylum Mollusca

33. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings There are four major classes of mollusca: Table 33.3 – Polyplacophora (chitons) – Gastropoda (snails and slugs) – Bivalvia (clams, oysters, and other bivalves) – Cephalopoda (squids, octopuses, cuttlefish, and chambered nautiluses) Phylum Mollusca

34. Table 33-3

35. Fig. 33-16

36. Fig. 33-17 (a) A land snail (b) A sea slug

37. Fig. 33-18 Mouth Anus Mantle cavity Stomach Intestine

38. Fig. 33-19

39. Fig. 33-20 Mouth Digestive gland Mantle Hinge area Gut Coelom HeartAdductor muscle Anus Excurrent siphon Water flow Incurrent siphon Gill Gonad Mantle cavity Foot Palp Shell

40. Fig. 33-21 Octopus Squid Chambered nautilus

41. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Phylum Annelida Annelids have bodies composed of a series of fused rings (segmented) The phylum Annelida is divided into three classes: Table 33.4 – Oligochaeta (earthworms and their relatives) – Polychaeta (polychaetes) – Hirudinea (leeches)

42. Table 33-4

43. Fig. 33-22 Epidermis Circular muscle Longitudinal muscle Dorsal vessel Chaetae Intestine Nephrostome Fused nerve cords Ventral vessel Metanephridium Septum (partition between segments) Coelom Cuticle Anus Metanephridium Crop Intestine Gizzard Ventral nerve cord with segmental ganglia Blood vessels Subpharyngeal ganglion Mouth Cerebral ganglia Pharynx Esophagus Clitellum Giant Australian earthworm

44. Fig. 33-23 Parapodia

45. Fig. 33-1

46. Fig. 33-24