Flatworms and Round Worms!

Phlylum Platyhelminthese = Flatworms

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

New Innovations in Excretory System cellular waste still removed by diffusion Protonephridia (NEW) flame cells help regulate solute concentration Evolve in to the nephrons of mammal kidneys First Kidney

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

Ancestral Traits Gastrovascular cavity for digestion & circulation Mouth in center of body Respiration (gas exchange) by diffusion http://www.youtube.com/watch?v=MeJQdbMge84 feeding flatworm

Free-living Flatworms = Class Turbellaria Marine Fresh-water

Flukes = Class Trematoda Parasites of blood and liver

Swimmer’s Itch =Schistosoma

Tape Worms = Class Cestoda

Human Tape Worm Sources =Under cooked Prevention Beef (N. America) Pork(S. America) Fish (Asia) Prevention Cook your meat!!!

Round Worms = Phylum Nematoda 1st Animal with a body cavity =pseudocoelom Fake body cavity – just a space between layers.

Types of body cavity (coelom) Acoelomate Pseudocoelomate Coelomate

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

Alimentary Canal

Spicule injects sperm for internal fertilization Spicule inside body Spicule extended

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

Hookworm in Humans Eggs in feces on ground Juviniles live in soil juviniles burrow into human skin Travel in bloodstream to lungs Juvilinles coughed up & swallowed Mature in small intestine Adults suck blood from intestine wall (cause anemia) Common in Southern States

Heartworm Larva in Blood