Invertebrates

1. Invertebrates 97% of the animal kingdom

2. Porifera • Pore bearing • Sponges • Heterotrophic, multicellular w/o a cell wall • No gastrula stage and no true tissues • Mostly marine – 5000 species in total • Sessile (attached to surfaces)

3. Structure • Two layers of cells w/ a jellylike substance • Inner layer made of flagellated cells called choanocytes (collar cells) • Used to draw water into pores on its sides • Water pumped out main anterior opening - Osculum

4. Skeleton • Simple • Network of flexible fibers called spongin • Seleton of spicules made of calcium carbonate or silica

5. “Digestive System” • Filter feeders using choanocytes • Choanocytesingest and digest food • Amoebocytes crawl w/i body wall to deliver food

6. Reproduction • Basically asexual by budding • Gemmules (internal buds) produced in adverse conditions • Capable of regeneration (growing back missing cells, tissues or organs • Also reproduced sexually • Hermaphroditic – contain both sexes

7. Cnidaria • Stinging celled animals • Radial symmetry • Tissues and simple organs • Basically marine • Jellyfish, coral and anemones

8. Structure Polyp • Body for is either polyp ormedusa • Two cell layers • Hollow gut called gastrovascular cavity • One body opening • Tentacles surround mouth/anus Medusa

9. Feeding and Defense • Cnidocytes – stinging cells • Nematocyst – harpoon like structure w/ a neurotoxin

10. Nervous system • No brain • Nerve net • Web of nerves throughout body • Stimuli trigger signals and entire body contracts

11. Hydra • Polyp form only • Freshwater • 1 – 4 cm • Reproduce sexually or by budding • Can move by forming a bubble at base • Uses tentacles and cnidocysts to capture and engulf prey • Feeding

12. Hydra Budding

14. Platyhelminthes • Flat worms • Developed from three germ layers • Bilateral symmetry • Acoelomates • No circulatory system or respiratory systems • Gastrovascular cavity • Hermaphroditic • Able to regenerate • Show definite cephalization • Planaria, flukes tapeworms

15. Planaria • Freshwater scavenger • Pharynx for ingestion • Extracellular digestion in gastrovascular cavity • Flame cells eliminate excess water • Cerebral ganglia as simple brain • Eyespots for photoreception

16. Nervous & Reproductive Excretory & Digestive Flame cells Regeneration in Planaria

17. Tapeworm • Live in intestines of vertebrates • Enter host through undercooked or raw meat containing eggs • Scolex for attachment • Proglottids –segments containing reproductive cells

18. 28 ft human tapeworm

19. Liver Fluke Attach to blood vessels of host Cause Schistosomiasis - bloodvessels are penetrated and gets into tissues

20. Nematodes • Round worms • Bilateral symmetry • Pseudocoelomate w/ fluid filled cavity • 1mm – 120cm (4ft) • Have a one way digestive tract (mouth – anus) • Separatesexes • Cuticle covering body • Free-living but some parasitic (50 in humans). • Soil dwelling destroy crops

21. Hookworm Ascaris Trichinella - trichinosis Pinworm Filarial worms - elephantiasis

22. Mollusca Soft bodied animals Clams, snails, slug, squid and octopi Coelomates Trochophore larvae – ciliated & freeswimming Body in 2 regions head – mouth & sensory organs foot – muscular for movement Visceral mass – above head containing all organ systems Mantle – covers visceral mass

23. Three types of Mollusks Gastropods – snails & slugs Radula scrape food Bivalves – clams, oysters 2 halves Siphons for feeding Cephalopods – squid & octopus Tentacles w/ suction cups Advanced nervous system Contain chromatophores

24. Annelids Segmented worms “Little rings” Earthworms, leeches & feather duster worms Bilateral symmetry Coelomate Setae – bristles for anchoring

25. Earthworm movement 2 sets of muscles longitudinal – shrink up circular – get longer Setae for anchorage

26. Feeding & Digestion Mouth Pharynx – sucks in soil Esophagus Crop – Storage area Gizzard – grinds soil Intestines – where chemical digestion occurs Typhlosole – fold in intestines to increase surface area Anus

27. Circulation Closed circulatory system Blood contains hemoglobin 5 aortic arches connect dorsal to ventral blood vessels

28. Excretion and Respiration Paired Nephridia present in each segment to remove wastes Exchange gases through blood vessels in skin. Skin must be kept moist with mucus

29. Nervous system Dorsal paired cerebral ganglia Nerve cord wraps around esophagus to fuse into a ventral nerve cord with ganglia

30. Reproduction Hermaphrodites Held together by setae & mucus film from clitellum Worms swap sperm & store it in the seminal receptacles Separate –Chitin ring around eggs & stored sperm. Hatch in 2-3 weeks

31. Leeches Freshwater No setae Sucker at each end for attachment Secrete anesthetic & anticoagulant Ingests 10x weight in blood Used in medicine for blood clots or hematomas

32. Arthropods 2/3 of all animals Bilateral coelomates Spiders, insects, crustaceans “Jointed foot” Exoskeleton of chitin – must mold to grow High degree of cephalization Segmented bodies –head, thorax, abdomen Compound eyes Antennae Open Circulatory systems Subphylum: Crustacea - lobster, shrimp, sowbugs, barnacles Chelicerata – spiders, scorpions, horseshoe crab Myriapoda – Millipedes & Centipedes Hexapoda – aka Insects

34. Crustacea Has two pair of antennae Mandible - Chewing mouthpart Sowbugs, crab, lobster, shrimp, barnacles Cephalothorax

35. Chelicerata Spiders, scorpion, ticks, mites, horseshoe crab 1st paired appendage are Chelicera– pinchers or fangs 8 legs Cephalothorax Book lungs or book gills

36. Insects 920,000 species identified Body in three parts Thorax w/ 3 jointed legs 2 pairs wings Abdomen segmented w/o wings nor legs One pair of antennae Compound eye

37. Insects and People Competes w/ us for food 10-20%/year loss of crops Spread disease Destroy houses – termites Pollinators – 40% of all plants Honey, wax, silk & shellac Decay of wood – termites Recycle nutrients from dead

38. Insect Development Incomplete metamorphosis Egg – nymph – adult Grasshoppers, dragonflies Complete metamorphosis Egg – larva – pupa – adult Flies, moths, butterflies

39. Echinodermata Sea star “Spiny skinned” Sea stars, sand dollars, sea urchins, sea cucumbers Radial symmetry No cephalization Bilateral larvae Deutrostomes All marine Able to regenerate

40. Structure Endoskeletons of calcium carbonate plates called ossicles Water Vascular system and Tube feetfor movement, food getting respiration & excretion

41. Food getting Uses tube feet to hold onto prey. Inverts cardiac stomach into prey Pyloric stomach secretes digestive juices. Then absorbs digested animal