4. 1. TRIPOBLASTIC 1. TRIPOBLASTIC: have 3 germ layers: Ectoderm: outside – skin and nervous system Endoderm: inside – lines internal organs, vessels (ie: guts, arteries) Mesodermmuscle *Mesoderm: middle – everything else, esp. muscle

5. ACOELOMATE:2. ACOELOMATE: ==NO BODY CAVITY (NO COELOM) = NO ORGAN SYSTEMS

7. 3.BILATERAL SYMMETRY 3.BILATERAL SYMMETRY: -have a “brain” in the anterior end -if you cut a flatworm in half (along the mid-dorsal line from anterior to posterior) you will have two equal pieces. This only works one way. mid dorsal cut

8. 4. NERVOUS SYSTEM 4. NERVOUS SYSTEM : - have a better nervous system - called a NERVE LADDER -gives them better discrimination (they can tell left from right).

10. 5.SENSORY APPENDAGES 5.SENSORY APPENDAGES (ANTERIOR END): -eyespots -auricles eyespots auricles

12. 6. DIGESTIVE SYSTEM: -incomplete digestive system -GVC (gastrovascular cavity) -MOUTH but still NO ANUS -PHARYNX ‘vacuums up food’ -gut is highly branched and transports food to all cells in body

14. 7. EXCRETORY SYSTEM: -gets rid of nitrogenous wastes & excess water -a specialized contractile vacuole -called “flame cell” -as it gets filled up, it moves to the edge of the worm, contracts and releases its contents outside the worm

15. 8. RESPIRATORY SYSTEM: -NO LUNGS! -get oxygen as it diffuses across their thin body wall -that is why they are flat as no cell can be too far from the outside

16. 9. REPRODUCTIVE SYSTEM: Asexually -amazing regeneration ability -cut in half = 2 new identical worms

17. 9. REPRODUCTIVE SYSTEM: Sexually -hermaphrodites (each individual is male & female) -all flatworms have eggs and sperm -to have sex, 2 worms exchange sperm and both have offspring

18. Flatworms are hermaphrodites When flatworms encounter each other, they engage in a 60 minute ‘dance’ during which they repeatedly strike at each other, both trying to inject their sperm under the skin of the other worm. The ‘winner’ becomes the male for that encounter, and the ‘loser’ must care for the fertilized eggs.

21. 10. PARASITISM: -when larger, more complex organisms with coeloms evolved, the flatworms became easy prey -the larger organisms ate the flatworms -the flatworms took advantage of their flat shape to hide inside the body cavities. -they adapted and evolved: a) hooks and suckers to hold fast b) a unique tegument (skin layer) to protect them from their hosts defenses. There are now more species of parasitic flatworms, flukes and tapeworms then there are free living forms.

25. TAPEWORMS are intestinal parasites in vertebrates. Very simple: no nervous system (no senses or brain), no digestive system, no excretory system, and no muscles. Has a very well developed reproductive system. They compete with us for OUR food.

26. TAPEWORMS Special structures: 1 – body segments = PROGLOTTIDS 2 – SCOLEX with: a) hooks b) suckers

30. SCOLEX

32. TAPEWORMS How to prevent yourself from getting tapeworm: 1 —cook your meat WELL DONE 2 —TREAT the sewage.

34. In digestive system: http://www.youtube.com/watch?v=T6pAfQInf2c Tapeworm coming out of cat: http://www.youtube.com/watch?v=FjBZmEwcd3s

37. FLUKES -Are all parasitic -Have complex life cycles -Specialized body parts: 1. Oral Sucker 2. Posterior Sucker -Many infest humans: heart flukes blood flukes liver flukes lung flukes intestinal flukes

40. Liver Flukes Removal of a liver fluke: http://www.youtube.com/watch?v=1XId87aphbQ

43. SHEEP WITH A CHRONIC LIVER FLUKE INFECTION

44. Blood Flukes

46. Blood fluke: http://www.youtube.com/watch?v=TI1BLXk7uiw

51. No vaccines have been developed that are effective against lung or liver fluke infections. Prevention of these infections includes the following measures: · boiling or purifying drinking water · avoiding raw or undercooked fish or salads made from fresh aquatic plants; all food eaten in areas with fluke infestations should be cooked thoroughly; pickling or smoking will not kill fluke cysts in fish or shellfish · control or eradication of the snails that serve as the flukes' intermediate hosts

53. FREE LIVING FLATWORMS -Are NOT usually parasitic -predators, but will eat dead things as well -have eye spots to detect light -eat meat -live in oceans, freshwater, and moist places on land (terrestrial) Triclads play an important role in watercourse ecosystems and are often very important as bio-indicators -Specialized body parts: 1. auricles 2. eyespots 3. pharynx

54. 1. Pharynx 2. Auricle 3. Eye spot 4. Pharynx 5. Gastrovascular cavity

55. REGENERATION Planaria can be cut into pieces, and each piece can regenerate into a complete organism. Very small pieces of the planarian, estimated to be as little as 1/279th of the organism it is cut from, can regenerate back into a complete organism over the course of a few weeks

57. FREE LIVING WORMS

59. Planaria are hermaphrodites (have testes & ovaries) Sexual Reproduction: -2 worms each transport their sperm to another planaria -the gametes join = zygote -this is shed from the body in a capsule -weeks later they hatch Asexual Reproduction: -planaria detaches its tail and each half regrows the lost parts via regeneration.

60. Planaria: http://www.youtube.com/watch?v=A6N8KZqGAJg Regeneration in Planaria (start at 1 min): http://www.youtube.com/watch?v=MFpotuZ- j2M&feature=related Land Planarian in Borneo: http://www.youtube.com/watch?v=Fq_aSR5FK0Y http://www.youtube.com/watch?v=Fq_aSR5FK0Y WATCH PLANARIA MOVING!

66. http://www.youtube.com/watch?v= HekwSO6dBG0&feature=related

67. Some free living flatworms prey upon cnidarians. Especially their tentacles (with cnidocytes). -They eat the cnidocytes without firing its toxic stinger. -Then the cells migrate from the digestive system to the epidermal surface -The flatworm then uses the cnidocytes (with their nematocysts) to defend itself! Cool!

68. Hunter: -kills earthworms -ruins soil