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Nematoda. Jenny Brooke David Thursday, March 13, 2014 Period 1. http://www.stanford.edu/group/parasites/ParaSites2006/Loiasis/Home.html. Sample Animals and Pictures. Caenorhabditis elegans Tricinella spiralis. David Dallas-Orr. Body Cavity (coelom) present or absent. Have a coelom
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Nematoda Jenny Brooke David Thursday, March 13, 2014 Period 1 http://www.stanford.edu/group/parasites/ParaSites2006/Loiasis/Home.html
Sample Animals and Pictures • Caenorhabditis elegans • Tricinella spiralis David Dallas-Orr
Body Cavity (coelom) present or absent • Have a coelom • Nutrients are transported in the fluid in the pseudocoelom • The fluid under high pressure David Dallas-Orr
Body Symmetry • Bilaterally symmetrical David Dallas-Orr
Nervous System • Nematodes have a reasonably well developed nervous system. • This is comprised of a circum-pharyngeal nerve ring made up from 4 nerve ganglia from which 6 longitudinal nerves extend down through the body • There are also 6 shorter nerves which extend forwards towards the mouth. David Dallas-Orr
Circulatory System • Lacks a circulatory system David Dallas-Orr
Digestive System • Alimentary canal: digestive canal issuing a track from mouth to anus http://classes.seattleu.edu/biology/biol235/hodin/nematodePriapulidGroup/nematodes/formAndFunction.htm#excretory Pathway of food: mouth (stoma) pharynx intestines rectum anus Jenny Kim
Excretory System • Nitrogenous waste is excreted through body wall • Rennette gland to excrete salt to maintain osmoregulation. Jenny Kim
Locomotion/Musculature • Only longitudinal muscles for movement • Moves by undulations or wave-like motions of the body. This produces a thrashing movement. http://classes.seattleu.edu/biology/biol235/hodin/nematodePriapulidGroup/nematodes/locomotion.htm Jenny Kim
Skeletal Type • Hydostatic skeleton: Non-compressible fluid enclosed and pressurized in body cavity. • Tough cuticle that coats body • Cylindrical and un-segmented http://www.newscientist.com/gallery/mg20327161300-enemy-within-human-parasites/3 Jenny Kim
Nematodes have peripherally located sense organs. Recent studies revealed the presence of true cilia in nerve processes connected with sensory organs. The body is covered in sensory bristles and papillae that provide a sense of touch. SENSORY STRUCTURES/FEATURES http://www.ucmp.berkeley.edu/phyla/ecdysozoa/nematoda.html Brooke Goycochea.
A female may deposit 100,000 or more fertilized eggs per day. Different species of nematodes have various ranges of modes of reproduction. Reproduction is usually sexual and most nematode species are dioecious. Some species, however, are hermaphroditic. REPRODUCTION http://w3.rennes.inra.fr/umrbio3pE/equipes/nematodes/images/lamelle-460.jpg Brooke Goycochea.
Have an alimentary canal but no circulatory system. Respiration and gas exchange occur by diffusion across the body wall. Both anaerobic and aerobic metabolism is common. GAS EXCHANGE http://www.ars-grin.gov/ars/SoAtlantic/fp/stpp/burelle/nematode.jpg Brooke Goycochea.
About 25,000 species are known but about 20 times more exist. There is little known about each nematode species even though they are numerous. It is said that if nothing but nematodes existed, they would preserve the outline of Earth and its many features. Humans host at least 50 nematode species. Unique Features of Nematodes http://www.ucmp.berkeley.edu/phyla/ecdysozoa/nematodesm.jpg Brooke Goycochea
Quiz • 1. Which of the following do not have a Hydrostatic skeleton for support? • A. Cnidaria • B. Platyhelminthes • C. Nematoda • D. Annalida • 2. Which of the following have a circulartory system? • A. Cnidaria • B. Platyhelminthes • C. Nematoda • D. Annalida • 3. Which of the following does not has a different body symmetry in the group listed below? • A. Cnidaria • B. Mollusca • C. Nematoda • D. Chordata • What type of body symmetry does each of the different phyla have? (listed above)
Quiz • 1. Which of the following do not have a Hydrostatic skeleton for support? • A. Cnidaria • B. Platyhelminthes • C. Nematoda • D. Annalida • 2. Which of the following have a circulartory system? • A. Cnidaria • B. Platyhelminthes • C. Nematoda • D. Annalida • 3. Which of the following does not has a different body symmetry in the group listed below? • A. Cnidaria • B. Mollusca • C. Nematoda • D. Chordata • What type of body symmetry does each of the different phyla have? (listed above) • A - Radial B,C,D – Bilateral
Bibliography for beginning pix • http://riddlelab.msl.ubc.ca/images/maincelegans.jpg • http://images.google.com/imgres?imgurl=http://workforce.cup.edu/buckelew/images/Trichinella%2520spiralis%2520male.jpg&imgrefurl=http://workforce.cup.edu/buckelew/Trichinella%2520spiralis%2520male.htm&usg=__-N5OebYUengR9rzBklrnegm5b0Q=&h=512&w=640&sz=27&hl=en&start=1&um=1&itbs=1&tbnid=To3n2v9H1z6ALM:&tbnh=110&tbnw=137&prev=/images%3Fq%3DTrichinella%2Bspiralis%26um%3D1%26hl%3Den%26sa%3DG%26ndsp%3D20%26tbs%3Disch:1 • http://www.cals.ncsu.edu/course/zo150/mozley/fall/nematode.jpg • http://www.nottingham.ac.uk/bennett-lab/nematode.jpg • http://web.pml.ac.uk/nematode/pictures/images/nematode5.jpg