Flatworms/ Roundworms

1. Flatworms/ Roundworms By: Alexey Pomogaev, Daniel Cho, Connor Healey

2. Flatworms and Roundworms • Flatworms • Phylum- • Platyhelminthes • Class- • Turbellaria, Cestoda, Trematoda, Monogenea • Families- • 102 variations • Roundworms • Phylum- • Nematoda • Class- • Adenophorea, Secernentea, • Families- • A LOT (Pseudocerosbimarginatus) (Enterobiusvermicularis)

3. Evolution • Flatworms: • Scientists don’t really know • Parasitic flatworms probably evolved from free-living animals • Roundworms: • Scientists believe the roundworms lived somewhere in the Proterozoic Era (1+ billion years ago)

4. Flatworm Anatomy

5. Roundworm Anatomy

6. Symmetry/Body Cavity • Flatworms: • Bilaterally symmetrical • 3 germ layers – ecto-, meso-, endo-, -derms that press against each other • Gastrovascular cavity-gut with 1 opening • Acoelomates- lack a hollow body cavity • Roundworms: • Bilaterally symmetrical • Pseudocoelomates-have a hollow fluid filled cavity lined by mesoderm outside and endoderm inside

7. Structural Support • Flatworms: • Varying structural systems including proglottids or sections, tegument or an outer layer of proteins and carbohydrates • Roundworms: • Hydrostatic skeleton

8. Nutrition/Digestion • Flatworms: • Turbellarians, monogeneans, and trematodes have a digestive system, but cestodes don’t • Mouths are on the front or side of the head • Turbellarians are always non-parasitic, while monogeneans, trematodes and csetodes are parasites, usually found on or inside an organism • Flatworms eat small worms, insects and microscopic matter • Roundworms: • Can be herbivores, omnivores, or carnivores • Mouth to pharynx to intestine to anus

9. Transportation/Circulation • Flatworms: • No formal circulatory system • Cilia & muscles • Roundworms: • Use muscles and the fluid in their pseudocoelum to make a “hydrostatic skeleton” • Aquatic worms use these muscles to swim, while terrestrial worms thrash around • No formal circulatory system

10. Respiration • Flatworms: • No formal respiratory system • Being extremely thin, flatworms can exchange gases, mainly oxygen and carbon dioxide, directly with their environment through diffusion • Roundworms: • No formal respiratory systems • Oxygen is diffused through the environment

11. Water Balance/Excretion • Flatworms: • Excretion & eating both use the same opening • Protonephredia and flame cells regulate water balance • Water balance or osmoregulation is maintained by protonephridia, which terminate in specialized flame cells • Roundworms: • Fecal matter exits through the anus

12. Reproduction • Flatworms: • Sexual: • Fertilization is internal • Eggs are ectolecithal; the ova are provided with yolk cells and the egg mass is surrounded in a capsule. • Asexual • Very frequent • Turbellarians reproduce by fragmentation or binary fission. • Roundworms: • Sexual: • Males have testes, where females have ovaries • Fertilization is internal

13. Nervous System • Flatworms: • Organizaton of ganglia is a central region of nerve processes. • Nerve cords are usually arranged in symmetrical pairs. • Roundworms: • Consist of a large circumesophageal commissure -nerve ring. • There are commissures that interwoven the ventral nerve cord with the lateral or dorsal nerves • Lateral nerves are primarily sensory. • The dorsal and ventral nerve cords are motor.

14. Unique Characteristics • Flatworms: • They are studied for their regenerative abilities. • Cause pathological troubles or difficulty in marine ornamental fishes. • Roundworms: • Parasitic adenophoreans aid plants in receiving diseases. • cause dehydration and loss of nutrition in plants. • Help to cycle carbon and nitrogen

15. Resources • Starnes, Robert (2002). Flatworms and roundworms. Retrieved April 11, 2009, from Essortment Web site: http://www.essortment.com/all/flatwormroundwo_rmhm.htm • Flatworms. Retrieved April 11, 2009, from Flatworm Web site: http://www.mcwdn.org/Animals/Flatworm.html • Klaus Rohde, C. G. Goodchild, "Platyhelminthes", in AccessScience@McGraw-Hill, http://www.accessscience.com, DOI 10.1036/1097-8542.527600 • (2006). University of Winnipeg EVOLUTION ECOLOGY AND BIODIVERSITY . Retrieved April 11, 2009, from PHYLUM NEMATODA Web site: http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg8.htm • Preisner, Thadd R. (2007, February 5). Flatworms. Retrieved April 11, 2009, from PENN STATE UNIVERSITY Web site: http://www.personal.psu.edu/users/t/r/trp2/flatworms.html • "Turbellarians: Turbellaria." Grzimek's Student Animal Life Resource. Ed. Catherine Judge Allen, Arthur V. Evans, Melissa C. McDade, Neil Schlager, Leslie A. Mertz, Madeline S. Harris, et al. Vol. 9: Corals, Jellyfishes, Sponges, and Other Simple Animals. Detroit: UXL, 2005. 78-87. Gale Virtual Reference Library. Gale. VERNON HILLS HIGH SCHOOL. 11 Apr. 2009 http://go.galegroup.com/ps/start.do?p=GVRL&u=vern39182 • "Roundworms: Adenophorea." Grzimek's Student Animal Life Resource. Ed. Catherine Judge Allen, Arthur V. Evans, Melissa C. McDade, Neil Schlager, Leslie A. Mertz, Madeline S. Harris, et al. Vol. 9: Corals, Jellyfishes, Sponges, and Other Simple Animals. Detroit: UXL, 2005. 132-136. Gale Virtual Reference Library. Gale. VERNON HILLS HIGH SCHOOL. 11 Apr. 2009 http://go.galegroup.com/ps/start.do?p=GVRL&u=vern39182 • Postlethwait, John H. (2006). Modern Biology. Austin, TX: Holt, Rinehart and Winston.