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Platyhelminthes

Platyhelminthes. (Flat Worms) By Master Broady Bloomer. Key Characteristics . The bodies of flatworms are soft, compressed a nd very thin. Flatworms are bilaterally symmetrical. Flatworms are invertebrates.

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Platyhelminthes

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  1. Platyhelminthes (Flat Worms) By Master Broady Bloomer

  2. Key Characteristics • The bodies of flatworms are soft, compressed and very thin. • Flatworms are bilaterally symmetrical. • Flatworms are invertebrates. • They are acoelomate which means they have no body cavity or internal support. • Flat worms are categorized as Platyhelminthes because they have eye spots and they are acoelomate .

  3. Anatomy • Flatworms have multiple different important body parts like eye spots, mouths, pharynx, and a ventrolateral nerve cord. • The pharynx is a membrane-lined cavity behind the mouth connecting to the throat. • The eye spots are not really eyes they just help them sense where they are. • Their mouths aren’t used for chewing, but it is where they bring food into their body.

  4. Digestion • Flatworms have a mouth where food comes in. • After food comes in it moves into the digestive system. • After all of the food has been digested and the nutrients gets absorbed, the waste comes back up through the mouth. • As you know by now the flat worm has no vent and a lot of the time flatworms have a host. • As Mr. Reuter said “That would take a lot of tic-tacks.”

  5. Respiration • Flatworms are animals so they take in oxygen and release carbon dioxide. • They breathe through their flexible skin. • They breathe using diffusion. • They breathe much like a toad. • Flatworms are flat so they can respire. No cell can be too thick.

  6. Internal Transport • Flatworms lack an internal transport system that can circulate oxygen to their whole body. • Because of the way they breathe they don’t need an internal transportation system. • They use diffusion to transport nutrients and oxygen to their cells. • They don’t have a heart or blood that need oxygen like humans. • Some flatworms have what are called flame cells which get rid of extra waste like water, some times flame cells filter the waste and take out ammonia and urea.

  7. Excretion • Flatworms also use diffusion for excretion purposes. • Some may use the specialized flame cells that excrete extra waste. • The flame cell has a system of tubules where It forces waste out. • The flame cell acts like a plug as well and stops water and other fluids from coming in. • Cilia projecting into the tubes beat and flicker pushing waste out when needed.

  8. Response • All flatworms have heads that store a ganglia. • Ganglia is a central nerve/control center this is the flatworms nervous system. • The ganglia is not sophisticated enough to be called a brain. • All flatworms have two long nerve cords that run along the sides of the worm and smaller ones that run perpendicular to the body of the worm. • Free living flatworms use the nerves more because they are not as protected as a parasitic worm.

  9. Movement • Flatworms use cilia to move. • Cilia on the epidermal cells that help them glide through water. • Flatworms also have muscles cells that help them twist and turn and are controlled by the nervous system. • The muscles are located on the inner most layer. • Some say that flatworms swim like snakes.

  10. Reproduction • Flatworms are hermaphrodites, so they have both male and female sexual organs. • When they sexually reproduce two flatworms come together and swap sperm and fertilize each others eggs. • They lay clusters of eggs and, and the eggs hatch in a few weeks. • Parasitic worms are more known to asexually reproduce. • They simply slit into two.

  11. Example • The Three Main types of flatworms are Turbellaria, Cestoda, and Trematoda. • PseudobicerosHancockanus • PseudobicerosBedfordi • Heterophydae • PseudocerosDimidiatus • Cestoda

  12. Facts • There are about 20,000 different types of flatworms. • About 38% of flatworms are free living. • There are 10,000 different types of parasitic flatworms. • Parasitic worms are often passed on by insects. • The average full sized free living flatworm is 30 millimeters long.

  13. Works Cited • http://www.blurtit.com/q463862.html • http://www.buzzle.com/articles/characteristics-of-platyhelminthes.html • http://www.infusion.allconet.org/webquest/PhylumPlatyhelminthes.html • http://ex-anatomy.org/flame.html • http://www.factmonster.com/search?fr=fmtnh&query=platyhelminthes&x=21&y=10

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