1. Flat Worm and Round Worms!

2. Flatworms had it FIRST!! Phylum: Platyhelminthes
Bilateral symmetry
Directional motion = 1st active predator
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 end
Sensory nerves formed bundles = ganglion
Eyespots detect light, Auricles detect chemicals ‘smell’
2 nerve cords transmit info to rest of body

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

4. 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!

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

6. Free-living Flatworms = Class Turbellaria
Marine
Fresh-water

7. Flukes = Class Trematoda
Parasites of blood and liver

8. Swimmer’s Itch =Schistosoma

9. Tape Worms = Class Cestoda

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

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

12. Types of body cavity (coelom)
Acoelomate Pseudocoelomate Coelomate

13. 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

14. Alimentary Canal

15. Spicule injects sperm for internal fertilization
Spicule inside body
Spicule extended

16. 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

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

18. Heartworm Larva in Blood