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Nematoda Gap Notes

Biology 11


Name: __________________________ Date: __________ Block: _____



Nematoda Anatomy










Biology 11

Mr. Carmichael

Name: ___________________ Date: __________ Block: _____



Phylum Nematoda: Roundworms

(Greek: nema = “thread”)

Pages 314-317


  1. Background:


  • 2 Major Classes:
    1. _______________________________
    2. _______________________________
  • ~ 80000 species known


DID YOU KNOW!!!: Nematodes are the most abundant multicellular lifeforms on earth!!!


  • The Nematodes have evolved to live in every habitat on the planet from marine to fresh water, the polar regions to the tropics and from the highest elevations to the lowest.
  • Nematodes can be _____________________ or _______________________


  1. Body Plan/Structure:
  • Nematodes demonstrate a ________________________ symmetrical body plan
  • They have a _________________and _______________________ body
  • They lack a ______________________
  • They have three germ layers:
    1. ______________________
    2. ______________________
    3. ______________________
  • Nematodes are the fist phylum we will look at that has a _________________ ____________________________ with a _________________ and an _____________ connected by __________________________
  • The mouth is connected to the intestines by a muscular ___________________
  • Nematodes are ___________________________ which means that they have an internal body cavity but this cavity is not lined with _______________________
  • They do have muscles but only ___________________________ ones
  • They have ____________________ in their __________________ end which is connected to two __________________________ that run down the length of the body on the ________________ and ____________________ sides
  • Nematodes secrete a thick _______________________ that surrounds the body and protects them from their surroundings


DID YOU KNOW!!!: Nematodes are born with the same number of cells that they will have for their entire life. This means that as Nematodes grow they do not get new cells; instead their cells just get larger!!!


III. Feeding:

  • The free-living Nematodes usually eat bacteria, fungi, protozoans along with other detritus (decomposing material)
  • Parasitic Nematodes live off of their host organism
  • Food is ingested through the mouth by muscular contractions of the ___________
  • The food is digested in the ________________________
  • Undigested food is passed out of the _______________


  1. Respiration:
  • Respiration occurs by simple _____________________ where oxygen is taken up by the body cells from the surroundings and carbon dioxide is released from the body cells into the surroundings


  1. Internal Transport:
  • The Nematodes lack a true _______________________________; However, nutrients diffuse from the intestines into the __________________________ where they circulate throughout the body


  1. Excretion:
  • Wastes and undigested nutrients are released out of the _____________.
  • They also have _____________________________________ on either side of their body which release wastes into the surroundings from the pseudocoelom



VII. Response:

  • Nematodes can have the ability to sense and respond to three stimuli:
    1. Sense and respond to ________________
    2. Sense and respond to ______________________
    3. Sense and respond to _________________


VIII. Movement:

  • Since Nematodes lack _______________________ muscles and only have ______________________ muscles they can only slash around from side to side


  1. Reproduction:


  • Sexual reproduction (free-living):
    • Most Nematodes are either ________________ or _______________ (though some are hermaphroditic)
    • When a female and a (much smaller) male Nematode meet, the male will wrap his ________________ around the female
    • One or more ______________ will move out of his anus and will be inserted into the females __________________ and sperm will be transferred
    • The fertilized eggs are released by the female into the surroundings


  1. Ecological Roles:

Parasitic Nematodes:

Like the Platyhelminthes there are many forms of Nematodes that are parasitic. They Are mostly parasitic on vertebrates and can cause serious illness. They also have very complicated lifecycles:


Eg. Trichenella spiralis (causes Trichinosis)

  • These Nematodes only need one host to mature but can be passed from host to host
  • The adult Nematodes live in the _______________ of their host (pig/rat/human)
  • When they undergo sexual reproduction the larva burrow into the muscles of their host and create a capsule around themselves called an _______________
  • After maturing the larvae travel back to the intestine to begin the lifecycle again


DID YOU KNOW!!!: Most Humans get Trichinosis from eating undercooked pork which

contains the larvae filled encysts!!!


Biology 11

Mr. Carmichael

Name: _________________________ Date: __________ Block: _____



Parasitic Nematoda Life Cycle

eg: Trichenella spiralis




posted by Marc Bernard Carmichael in Biology Eleven,Biology Eleven Notes and have No Comments

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