1 / 19

FLATWORMS

FLATWORMS. Belong to the KINDGOM ANIMALIA PHYLUM PLATYHELMINTHES. Characteristics. Three germ layers (endoderm, ectoderm, mesoderm) Bilateral symmetry Cephalization (has a head) COELOM = fluid filled body cavity Acoelomates = without coelom. FORM AND FUNCTION. FEEDING

vidar
Télécharger la présentation

FLATWORMS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. FLATWORMS Belong to the KINDGOM ANIMALIA PHYLUM PLATYHELMINTHES

  2. Characteristics • Three germ layers (endoderm, ectoderm, mesoderm) • Bilateral symmetry • Cephalization (has a head) COELOM = fluid filled body cavityAcoelomates = without coelom

  3. FORM AND FUNCTION FEEDING Free-living - carnivores or scavengers; they have a digestive cavity, mouth and pharynx Parasites – feed on blood, tissues or pieces of cells from within a HOST Most do not have a complete digestive system because they absorb material directly from host

  4. Respiration, Circulation, and Excretion • Thin bodies allow for materials to diffuse (respiration, excretion, etc) • Flame Cell – specialized cells that remove excess water

  5. Response Ganglia – group of nerve cells that control the body (like a brain) Eyespot – group of cells that can detect light (like an eye)

  6. Movement Flatworms move in 2 ways • Cilia helps them glide through the water • Muscle cells help them twist and turn

  7. Reproduction Sexual Reproduction – most flatworms are hermaphrodites (have both male and female sex organs) Asexual Reproduction by fission – flatworms can split in two and regenerate

  8. Groups of Flatworms CLASS TURBELLARIA - free living flatworms - live in fresh or marine water - ex. Planarian

  9. Dugesia lives in freshwater, mostly a scavenger but can also feed on protists

  10. Planarians are hermaphrodites They can also regenerate body parts and will sometimes split in half to reproduce (FISSION)

  11. ANATOMY OF A PLANARIAN

  12. Brain (ganglia) - planarian can process information about their environment Pharynx - used for suckling food in (the mouth is at the end of the pharynx) Eyespot - simple eye, can detect light Flame cells - located along the lateral edges, used for excretion Intestine - digestion (does not have an anus)

  13. Class Trematoda = parasitic flatworms • a.k.a “flukes” live in mouth, skin, or gills of host Primary host = the host in which a parasite reproduces sexually Intermediate host = the host in which asexual reproduction occurs

  14. Schistosoma mansoni - multiple host: Primary host = human Intermediate host = snail Causes Schistosomiasis -in humans; decays lungs liver, spleen, or intestines, occurs in tropical areas with poor sanitation/sewage.

  15. Class Cestoda =tapeworms Long, flat, parasitic Live in intestines

  16. Scolex = a structure that contains suckers and/or hooks Proglottids = body segments of the tapeworm

  17. Each mature proglottid is a hermaphrodite Testes produce sperm, fertilize the eggs to produce a zygote Zygotes are passed out through the feces.

  18. Sometimes, a dormant, protective cyst is formed in the intermediate host muscles ****This is why you should never eat incompletely cooked meat.

  19. Adapted from www.thebiologycorner.com

More Related