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

2. Sample Animals and Pictures
Caenorhabditis elegans
Tricinella spiralis
David Dallas-Orr

3. 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

4. Body Symmetry
Bilaterally symmetrical
David Dallas-Orr

5. 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

6. Circulatory System
Lacks a circulatory
system
David Dallas-Orr

7. Digestive System
Alimentary canal: digestive canal issuing a track from mouth to anus
Pathway of food: mouth (stoma)  pharynx  intestines  rectum  anus
Jenny Kim

8. Excretory System Nitrogenous waste is excreted through body wall
Rennette gland to excrete salt to maintain osmoregulation.
Jenny Kim

9. Locomotion/Musculature
Only longitudinal muscles for movement
Moves by undulations or wave-like motions of the body. This produces a thrashing movement.
Jenny Kim

10. Skeletal Type
Hydostatic skeleton: Non-compressible fluid enclosed and pressurized in body cavity.
Tough cuticle that coats body
Cylindrical and un-segmented
Jenny Kim

11. 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.
Brooke Goycochea.

12. 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.
Brooke Goycochea.

13. 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.
Brooke Goycochea.

14. 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.
Brooke Goycochea

15. 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)

16. 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

17. Bibliography for beginning pix