16 Flatworm Feeding Free living flatworms are scavengers. Parasitic flatworms use specialized structures (usually with hooks) to attach to a host.
17 Respiration & Excretion Excretion - Flame cells remove excess waterRespiration - Oxygen diffuses into body cells directly.
18 Flatworm Nervous Systems First appearance of cephalization.Primitive brain.Eyespots
19 Flatworm Reproduction Sexually - Hermaphrodites – internal fertilzation.Asexually – fission – when damaged, regenerates new body parts.Proglottids – found in tapeworms – each is shed off individually.
20 Roundworms - Nematoda Bilateral Symmetry Free-living in soil or parasitic in a hostPseudoomate – false body cavity.Movement - Longitutdinal muscles produce a thrashing movement
21 Respiration & Excretion Respiration - Oxygen diffuses into body cells.Digestive wastes are excreted through the anus.Flame cells remove excess water through pores in body surface.
22 Roundworm Feeding Have a simple digestive system. Have a mouth and an anusParasitic roundworms use specialized structures (usually with hooks) to attach to a host.
23 An Important GroupMany nasty parasitic infections in humans, livestockImportance and IMPORTANT AGRICULTURAL PESTPinworms, Ascaris, hookworms, Trichinella