Platyhelminthes

Lauren Wagner and Madison Page

5-19-09

3rd Period

TapewormHymenolepis diminuta

Fluke

Megaptera Novaeangliae

Classification• Trematoda- parasitic; 12,000 species; various suckers; infect 200 million people a

year; 4 hosts.

• Cestada- 3,500 species; parasitic; mouth no gut; live anywhere with vertebrates.

• Turbellaria- aquatic; move with cilia; asexual reproduction (fission)

• Mongenera- 1 host in life; endoparasitic; free swimming

Body• Bilateral symmetry.• Flattened• Ribboned shape• 3layers of body tissues with organs.• Blind gut- mouth no anus • The protonephndral excretory organs which replace the anus• No skeleton• Nervous system of longitudinal fibers • Unblinkable eyespots

Reproduction• Eggs pass out with the primary host's feces and eventually contaminate water, where

they are ingested by snails (the first intermediate host). • Eggs burrow into the digestive system.• Sporocyst forms a redia asexually.• It then leaves the snail and finds a fish host. It then affects the fish.

• Most species of flatworms reproduce either sexually or asexually

Digestive System

Flatworms absorb nutrients through their skin and excrete

wastes using specialized "flame cells."

There is only a mouth opening.

The mouth eliminates food.

Circulatory System• Transport oxygen, nutrients, and wastes through the body via a closed circulatory

system. • Blood travels from the anterior to the posterior through a ventral blood vessel and

then forward through a dorsal vessel. • Five pairs of tubes, the aortic arches, link the major vessels near the anterior. • Smaller vessels branch into each segment of the body.

• Contractions of the ventral vessel force blood through the body.

 

Respiratory System

Earthworms have no gills or other respiratory organs.

Oxygen and carbon dioxide diffuse directly across only moist skin.

(mucus and a thin cuticle also help keep the earthworm’s skin moist.)

Environment• Mainly found in aquatic areas.• Moist areas.• Marine, freshwater areas.

Human Interactions•  Over half of all known flatworm species are parasitic, Schistosomiasis, caused by

Infection of humans by the broad fish tapeworm Diphyllobothrium latum occasionally causes vitamin B12 deficiency.

• Platyhelminth parasites to humans with organic farming.• The popularity of raw or lightly-cooked foods, and imports of meat, sea food and

salad vegetables from high-risk areas.

Unique Features

• Can be 50 meters long.

• Need symbiotic relationships to survive fatty acids.

• Well developed nervous system.

Pictures

BibliographyGoogle. May 19th, 2009.

http://images.google.com/images?hl=en&q=platyhelminthes&gbv=2&aq=f&oq=

Platyhelminthes. May 19th, 2009.

http://zipcodezoo.com/Key/Animalia/Platyhelminthes_Phylum.asp

Platyhelminthes. May 19th, 2009.

http://www.discoverlife.org/20/q?search=Platyhelminthes

Angelfire. May 19th, 2009.

http://www.angelfire.com/ut/biocheat/PlatyhelminthesNemat.html

Platyhelminthes. May 19th 2009.

http://faculty.pnc.edu/jcamp/parasit/flatworm.html

Platyhelminthes. May 19th, 2009.

http://cas.bellarmine.edu/tietjen/images/platyhelminthes.htm

Phylum Platyhelminthes. May19th, 2009.

http://io.uwinnipeg.ca/~simmons/lb6pg6.htm

Platyhelminthes. May 19th, 2009.

http://www.bumblebee.org/invertebrates/PLATYHELMITHES.htm

Holt, Rinehart and Winston. Animals: Holt Science and Technology. Time Warning Company, 2000.

Tapeworms. May 21st, 2009.

http://animals.jrank.org/pages/1532/Tapeworms-Cestoda.html

Trematoda. May 21st, 2009.

http://www. answers.com/topic/trematoda

What Are Tapeworms. May 21st, 2009.

http://www.wisegeek.com/what-are-flatworms.htm

May 21st, 2009.

http://images.google.com/images?hl=en&um=1&sa=1&q=tapeworm&aq=f&oq=