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Platyhelminthes

Platyhelminthes. Daniel Jaffe Paige Minteer Zoey ZoBell.

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Platyhelminthes

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  1. Platyhelminthes Daniel Jaffe Paige Minteer Zoey ZoBell http://images.google.com/imgres?imgurl=http://www.divetrip.com/wakatobi/flatworm02.jpg&imgrefurl=http://www.divetrip.com/phot0410d.htm&usg=__j9-Bk4Alyot44vGWORfQmnPD2gI=&h=480&w=640&sz=123&hl=en&start=2&um=1&itbs=1&tbnid=9H_cUbqZE-qAXM:&tbnh=103&tbnw=137&prev=/images%3Fq%3Dflatworm%26um%3D1%26hl%3Den%26client%3Dsafari%26rls%3Den%26tbs%3Disch:1

  2. Phylum: Platyhelminthes Class Examples and Characteristics

  3. Sample Animals Dugisea Tapeworm http://gurungeblog.files.wordpress.com/2008/11/platyhelm_turbellaria_dugesia.jpg http://www.britishbeef.co.uk/tapeworm.gif

  4. Body Cavity • No body cavity exists within the Platyhelminthes • Considered an Acoelomates, which means without a cavity http://biology.unm.edu/ccouncil/Biology_203/Images/SimpleAnimals/Acoelomate.JPG

  5. Body Symmetry • Platyhelminthes exhibit bilateral symmetry, which means it has one line of symmetry, similar to humans. • A bilateral animal has a dorsal side and a ventral side • A bilateral animal has an anterior end and a posterior end. http://www.uic.edu/classes/bios/bios100/labs/bilateral.jpg

  6. Nervous System • Central Nervous system that processes information from the eyes and other sensory structures • The bilateral symmetry of this phylum allows for sensory equipment concentrated at the anterior end along with the central nervous system and the brain • This evolutionary tend is known as cephalization

  7. Circulatory System • No body or organs for circulation • Open system http://www.seaslugforum.net/images/flatworm.jpg

  8. Digestive System • Pharynx: a muscular tube in which the mouth is located • Extends form ventral side • Digestive juices are sprayed onto pray, and small pieces are sucked into pharynx, where digestion continues • Undigested wastes are egested through the mouth

  9. Excretory System • “Flat” shape in which nitrogenous waste (ammonia) is removed through diffusion across the body surface. • No organs specialized for gas exchange or circulation. They have a basic structure  excretory system is through osmotic balance with their surroundings.

  10. Locomotion/Musculature • Motility a.k.a “Going Dumb” • Move by using cilia on their ventral epidermis, gliding along a film of mucus that they secrete. • Some use muscles to swim through water with an up-and-down form of motion. http://www.glogster.com/media/2/3/71/6/3710611.jpg

  11. Skeletal Type • Platyhelminthes do NOT contain a skeleton type. • They can literally do the “worm” without risking any bone fractures.…holy biology! http://cyberportfolio.st-joseph.qc.ca/classes/carriere/archives/surprised-girl-reading-book.jpg

  12. Sensory Structures/Features • Ganglia: Located at the anterior end of the worm, they are dense clusters of nerve cells also known as eye spots • Ventral nerve cords: Coming from the ganglia, a pair of nerve cords that run down the lenth of the body.

  13. Reproduction Methods • Sexual and asexual reproduction • Regenerative tissues allow one split individual to regenerate into two separate worms • Mostly homaphrodite • Self fertilization as well as cross fertilization is seen • Direct development (no larva stage) http://cas.bellarmine.edu/tietjen/images/Chlonorchis01.gif

  14. Gas Exchange • Lack respiratory systems • Flat bodies permits flow of oxygen and carbon dioxide by diffusion http://cas.bellarmine.edu/tietjen/images/platyh16.jpg

  15. Unique Features • Restricted to living in wet environments because of the nature of their open gas exchange making them susceptible to dehydration • Their bodies are soft, unsegmented, and resemble ribbons • Some of these species are carnivorous, while the rest are parasitic • Tapeworm disease, or, Cestodiasis is caused by a parasitic type of Platyhelminthes

  16. The End Thanks for listening!

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