1. H ONORS B IOLOGY : R OUNDWORMS ( CONTINUED ) F EEDING, R ESPIRATION, C IRCULATION, E XCRETION, R ESPONSE, M OVEMENT, R EPRODUCTION & T YPES Mr. Gibson Room 213 w/o May 9th

2. R OUNDWORMS : CONTINUED Review of structure (physiology) They have a “ hydrostatic skeleton ” (water – not moving) due to a fluid filled gastrovascular cavity that contains NO complex digestive organs, but DOES have two openings – mouth & anus.

3. R OUNDWORMS : CONTINUED Review of structure (physiology) The “hydrostatic skeleton” is caused by the fluid inside the endoderm lined gastrovascular cavity pushing outward (like a water balloon does as is fills up). This outward force (by the fluid) is called tugor pressure.

4. R OUNDWORMS : CONTINUED Review of structure (physiology) In summary: The “hydrostatic skeleton” caused by the fluid filled endoderm lined gastrovascular cavity pushing outward as tugor pressure … […] classifies roundworms as pseudocoelomates. (“pseudo” = “like”)

5. R OUNDWORMS : CONTINUED Review of structure (physiology) The roundworm’s outer body (ectoderm) is “unsegmented”… which means it is smooth & without any rings or segments.

6. R OUNDWORMS : CONTINUED Reproduction The roundworms are “male” and “female” (NOT hermaphrodites). They rely on sexual reproduction. More specifically, internal sexual reproduction (means the male’s sperm fertilized the female’s egg INSIDE her body).

7. R OUNDWORMS : CONTINUED Feeding The roundworms’ mouth has “grasping mouth pieces” which means they can grip and hold onto their prey (host) as they feed off of them. This also makes them parasitic heterotrophic carnivores.

8. R OUNDWORMS : CONTINUED Respiration, circulation, & excretion: Like flatworms… roundworms use diffusion through their body walls [to] move gases & materials into/out of their cells. They have no internal transport system (digestive system, blood circulatory system, or breathing system)

9. R OUNDWORMS : CONTINUED Response: Roundworms… like flatworms have a simple nervous system consisting of the same: a) ganglia (nerve ring) b) ventral nerve chords (that run the length of the body) c) transverse nerves They also have chemical & vibratory sensors for locating prey & predators.

10. R OUNDWORMS : CONTINUED Movement:Roundworms have muscles that run the length of their bodies. The fluid in the pseudocoelom combined with the muscles serve to expand & contract thus “move” the animal by “pushing” or “pulling” themselves along. http://animal.discovery.com/videos/monsters- inside-me-the-baylisascaris-parasite.html

11. R OUNDWORMS : CONTINUED Four major types of roundworms: Roundworms are classified as being: 1. Trichinosis-causing; 2. Filarial; 3. Ascarid; 4. Hook.