PHYLUM NEMATODA

1
PHYLUM NEMATODA

• ROUNDWORMS

2
ROUNDWORMS

• ORGAN LEVEL OF ORGANIZATION
• 3 GERM LAYERS
• BILATERAL SYMMETRY
• NONSEGMENTED
• TUBE TYPE DIGESTIVE TRACT
• MOUTH AND ANUS

3
ROUNDWORMS

• PSEUDOCOELOMATE
• HYDROSTATIC SUPPORT
• NERVE RING W/ DORSAL VENTRAL NERVE CORDS
• LONGITUDINAL MUSCLES
• DIFFUSION
• RESPIRATON
• CIRCULATION

4
ROUNDWORMS

• NO METHOD OF ASEXUAL REPRODUCTION
• SEPARATE SEXES - MALES AND FEMALES

5
ROUNDWORMS

• HABITAT AQUATIC, TERRESTRIAL
• SOME FREE LIVING
• SOME PARASITES
• CUTICLE
• NUTRITION
• SCAVENGERS
• CARNIVORES
• PARASITES

6
ROUNDWORM PARASITES

• ASCARIS
• HOOKWORM - ANCYLOSTOMA
• PINWORM - ENTEROBIUS
• TRICHINELLA - CAUSES TRICHINOSIS
• FILARIA - CAUSES ELEPHANTIASIS
• PLANT NEMATODES

7
OTHER EXAMPLES

• VINEGAR EELS
• WHIPWORMS

8
EVOLUTIONARY MILESTONE

• ONE WAY TUBE GUT W/ 2 OPENINGS
• PSEUDOCOELOM
• DISTINGUISHABLE SEXES

9
PHYLUM ROTIFERA

• ELONGATED, CYLINDRICAL BODY
• HEAD, TRUNK, FOOT
• CILIATED CORONA
• TELESCOPIC BODY
• PART OF PLANKTON
• FOOD SOURCE FOR AQUATIC ORGANISMS

10
Figure 25.17Page 425
Body Plan of a Rotifer
one of two ciliated lobes at head
mouth
cluster of nerve cells
modified pharynx
gastric gland
protonephridium
stomach
intestine
cloaca
anus
gland that secretes cementing substance for toe
one of two toes