Flat Worm and Round Worms!

Flatworms had it FIRST!! Phylum: Platyhelminthes Bilateral symmetry & TriploblasticBilateral symmetry & Triploblastic Directional motion = 1 st active predatorDirectional motion = 1 st active predator Cephalization – development of a ‘head end’Cephalization – development of a ‘head end’ –Ganglia: bundle of nerve cells make up a pre-brain Nerves concentrated at ‘head end’ since sensory cells were concentrated at that endNerves concentrated at ‘head end’ since sensory cells were concentrated at that end Sensory nerves formed bundles = ganglionSensory nerves formed bundles = ganglion Eyespots detect light, Auricles detect chemicals ‘smell’Eyespots detect light, Auricles detect chemicals ‘smell’ –2 nerve cords transmit info to rest of body

New Inovations in Excretory System Nitrogenous metabolic waste still removed by diffusionNitrogenous metabolic waste still removed by diffusion Protonephridia (NEW)Protonephridia (NEW) flame cells help regulate solute concentrationflame cells help regulate solute concentration Evolve in to the nephrons of mammal kidneysEvolve in to the nephrons of mammal kidneys

Flatworm Reproduction 1 st internal fertilization1 st internal fertilization Evolutionary advantageEvolutionary advantage –Make fewer gametes –Save energy Hermaphrodites = make both eggs & spermHermaphrodites = make both eggs & sperm Evolutionary advantage = you can mate with any other member of your species that you can find!Evolutionary advantage = you can mate with any other member of your species that you can find!

Ancestral Traits Gastrovascular cavity for digestion & circulationGastrovascular cavity for digestion & circulation Mouth in center of bodyMouth in center of body Respiration (gas exchange) by diffusionRespiration (gas exchange) by diffusion

Free-living Flatworms = Class Turbellaria MarineMarineFresh-water

Flukes = Class Trematoda Parasites of blood and liverParasites of blood and liver

Swimmer’s Itch =Schistosoma

Tape Worms = Class Cestoda

Human Tape Worm Sources =Under cookedSources =Under cooked –Beef (N. America) –Pork(S. America) –Fish (Asia) PreventionPrevention –Cook your meat!!! –Wash your hands after using the restroom –Don’t drink contaminated water

Number of Embryonic Tissue Layers PoriferaPorifera CnidariaCnidaria Endodermis matures into gastodermisEndodermis matures into gastodermis Flatworms, Roundworms All more advanced phyla Ectodermis matures into epidermis

Round Worms = Phylum Nematoda 1 st Animal with a body cavity =pseudocoelom1 st Animal with a body cavity =pseudocoelom Fake body cavity – just a space between layers.Fake body cavity – just a space between layers. Pseudocoelom used as aPseudocoelom used as a Hydrostatic skeletonHydrostatic skeleton Longitudinal muscles only=Longitudinal muscles only= thrashing thrashing

Types of body cavity (coelom) Acoelomate Pseudocoelomate CoelomateAcoelomate Pseudocoelomate Coelomate

Digestive Tract 1 st Alimentary Canal = one way digestive tract with mouth at one end and an anus at the other1 st Alimentary Canal = one way digestive tract with mouth at one end and an anus at the other Evolutionary advantageEvolutionary advantageSpecialization Can eat new meal before the old one is finished processing

Alimentary Canal

Spicule injects sperm for internal fertilization Spicule inside bodySpicule inside bodySpicule extended

Ascaris…………………………… One of the mostOne of the most common parasite of humans Up to 64% ofUp to 64% of people in some S.eastern states Eggs injestedEggs injested on Vegetables or from Soil

Hookworm in Humans Eggs in feces reach the groundEggs in feces reach the ground Juviniles live and grow in soilJuviniles live and grow in soil 2 nd stage juviniles burrow into human skin2 nd stage juviniles burrow into human skin They enter the bloodstream & travel to lungsThey enter the bloodstream & travel to lungs Juvilinles are coughed up then swallowedJuvilinles are coughed up then swallowed They finish maturing in small intestineThey finish maturing in small intestine Adults in small intestine suck blood from intestine wall (may cause anemia)Adults in small intestine suck blood from intestine wall (may cause anemia) Common in Southern StatesCommon in Southern States

Heartworm Larva in Blood