1. Animal Diversity

2. I. Background Ancestors were Protists - choanoflagellates

5. Animal Characteristics • Multicellular • Heterotrophic • Eukaryotic • Ingestion (eating food)

6. Background cont’d • C. Classification – Major Branches pg 371

9. Background cont’d 1. Parazoa – lack true tissues Phylum Porifera 2. Eumetazoa – true tissues Divided by type of symmetry a. Radial b. Bilateral

10. Radial - top & bottom (also called oral & aboral) - no front & back or left & right

11. Bilateral - top (dorsal) - bottom (ventral) - head (anterior) - tail – (posterior)

13. Bilateral Organisms • In embryonic development in a stage called gastrulation germ (tissue) layers form which become tissues & organs • Radial organisms have only 2 of these layers – called diploblastic • Bilateral organisms have all 3 - triploblastic

14. 3 Germ Layers 1. Ectoderm – covers surface & forms outer covering (skin) & nerves 2. Endoderm – innermost forms digestive tract with its outpockets like liver (also lungs) 3. Mesoderm – middle layer forms muscles & most other organs

15. Types of triploblastic organisms • Acoelomates - no coelom - solid body, no cavity b/w gut & outer body - flatworms – Platyhelminthes • Psuedocoelomates – false coelom - fluid filled cavity separates dig. tract from outer body - cavity not lined with tissue

16. Types of triploblastic organisms cont’d 3. Coelomates - tissue lined fluid filled cavity “true coelom” - tissue layers connect to form mesenteries which suspend internal organs - coelom function - allows for growth & movement of internal organs

19. Coeloms are helpful and used to be used for phylogenetic trees. • Not used too much anymore – • Homework – Find out why they don’t use this anymore.

21. Bilaterians divided into 2 groups • Grouping based on embryo • Protostomes - blastopore becomes the mouth • Deuterostomes - blastopore becomes the anus

22. Detailed Nine Phyla Phylum Porifera - sponges - pore bearing - sessile – immobile - lacks all organ systems - depends on diffusion from water to cells - water filtering system allows for filter feeding

23. Porifera cont’d • water enters through pores b/c of choanocytes (flagellated cells also called collar cells) • exits through top opening • Amoebocytes take up and carry nutrients

24. Porifera cont’d • Reproduction - asexual – regeneration - sexual - most are hermaphrodites - external fertilization • Ancestors probably choanoflagellates (Protists that resemble choanocytes)

28. Phylum Cnidaria • Jellyfish, hydra, sea anemone • Radial symmetry • Gastrovascular cavity (gvc) - central dig. cavity w/extracellular dig. • Single opening functions as mouth & anus

30. Phylum Cnidaria cont’d • 2 body plans – polyp & medusa pg. 373

32. Phylum Cnidaria cont’d • carnivorous - tentacles w/cnidocytes (stinging cells) surround mouth - cnidocytes contain nematocysts that contain a stinger pg. 373

34. Cnidaria continued • Reproduction - asexual - budding - sexual - egg & sperm meet in water outside of body (external fertilization)

35. Phylum Platyhelminthes • Flatworms like planarian, tapeworm, & flukes • Bilateral symmetry • One opening to dig. tract - pharynx & gvc w/ branches • Pg. 374

38. Platyhelminthes continued • Reproduction - asexual – regeneration - sexual – hermaphrodites with cross fertilization (produce both egg & sperm but are unable to fertilize their own eggs)

42. Phylum Nematoda • Roundworms – trichenella, hookworms, aquatic or soil dwellers • Complete digestive tract - mouth & anus • Many are parasites • Caenorhabditis elegans (C. elegans) free-living and useful in genetic studies

43. Phylum Mollusca • Soft bodies, most protected by shell of calcium carbonate • Clams, oysters, snails

44. Phylum Mollusca cont’d • Body plan has 3 main parts 1. Foot – muscular for movement 2. Visceral mass – contains most internal organs 3. Mantle – heavy tissue drapes over visceral mass & may secrete shell - mantle pulled away in one area & contains gills, anus, & excretory pores

45. Phylum Mollusca continued • Many mollusks feed by a radulla – spiked tongue • Most have separate sexes

46. Mollusca Classes Gastropoda – one shell, stomach footed - snails & slugs - land dwellers - mantle cavity acts as a lung - aquatic – gills

48. Mollusca continued Bivalvia – 2 part shell - clams, oysters - gills used for filter feeding (suspension feeders) - radula lost

50. Mollusca continued Cephalopoda – head-footed - squid, octopus - shell reduced & internal - mouth at center w/tentacles - beaklike jaw for biting - closed circulatory sys.