Jenny Brooke David Friday, April 21, 2017 Period 1 Nematoda Jenny Brooke David Friday, April 21, 2017 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

SENSORY STRUCTURES/FEATURES 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. http://www.ucmp.berkeley.edu/phyla/ecdysozoa/nematoda.html Brooke Goycochea.

REPRODUCTION 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. http://w3.rennes.inra.fr/umrbio3pE/equipes/nematodes/images/lamelle-460.jpg Brooke Goycochea.

GAS EXCHANGE 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. http://www.ars-grin.gov/ars/SoAtlantic/fp/stpp/burelle/nematode.jpg Brooke Goycochea.

Unique Features of Nematodes 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. 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