Platyhelminthes Kim Paul Emelie Poirier Chloe Raitt Hailey Reagh
Introduction Platyhelminthes Flatworms 20,000+ known species Range in length Feed on animal material, algae Bilaterally symmetrical 3 cell layers Mostly hermaphroditic Live everywhere Moist environments
Evolution Soft, small bodies don’t produce a well fossilized record. Schistosome larvae, oldest subspecies found, discovered in Egyptian Mummies. Nothing concrete found before them. Believed to have first appeared around 550 MYA.
Biochemical aspects used to determine Tree of Life. Still discrepencies in Tree of Life with taxon relationships. Parasitic subgroup (Trematoda, Monogenea, and Cestoda) are believed to be monophyletic Acoela are believed to have a different ancestor. Evolution
Classification Phylum – Platyhelminthes Greek words Platy for flat Helminthes for worm Classes Cestoda (parasitic tapeworms) Trematoda (parasitic flukes) Turbellaria (free living Planaria)