1. Unit 3B Journal #1 9/19
Put a clean sheet of paper in your folder. Use the following SAT words based on what you’ve learned this school year. Must be related to an animal we’ve learned about! Malevolent- wishing evil to others Natal- pertaining to one’s birth Affable- easy to approach Lax- not energetic or stringent Indigent- in poverty

2. Zoology 9/17 Roundworm Quiz Friday 9/21 Vocab quiz Thursday 9/20
What are the traits of roundworms? 1. Nematode notes 2. Roundworm coloring/question sheet OR Roundworm drawing sheet(I have these) 3. Pick up roundworm study guide from me today-omit 23, 24, 25, 27, and 29

3. Phylum Nematoda

4. General Information:
Round, unsegmented bodies tapered at each end
Pseudocoelom- body cavity filled w/fluid that distributes oxygen & nutrients so don’t have circulatory system
Tube-within-a-tube body plan
2 body openings- mouth & anus
Size- microscopic to about 1 meter
Bilateral symmetry
Triploblastic
Most are free living
some are parasitic

5. II. Body
Cuticle-
Thin, tough outer skin may have spines or scales for protection.
Not easily digested by host
Most molt about 4x during life
Longitudinal muscle-
Produces thrashing motion
Creates S- or C-shaped curves

6. III. Digestion/Feeding
Parasitic, free living, saprobes (decomposers)
Mouth- buccal cavity
May have hooks or suckers for attaching (parasite)
Sensory organs (“lips”) may be present
c. Pharynx- muscular organ that rhythmically pumps food thru digestive tract
d. Intestine- long tubular organ where digestion/absorption occur
e. Rectum/Anus- end of digestive tract where wastes are excreted.

7. IV. Nervous System
Dorsal & Ventral Nerve Cord- run along upper & lower surface of body sending nerve impulses to anterior end.
Nerve ring- simple brain picks up stimuli from nerve cords.
amphids – anterior (towards the head) depressions used for sensing chemicals in the water
phasmids – posterior (towards the tail) depressions used for sensing chemicals in the water

8. V. Respiration
All roundworms breathe by diffusion of oxygen into moist skin and carbon dioxide out of moist skin.

9. VI. Excretory System Excretory ducts collect liquid waste
Excretory pores excrete collected liquid waste thru skin

10. VII. Reproductive system
Dioecious
Males are usually smaller than females
Most lay eggs that hatch into larva- oviparous
Some give birth to live larva- viviparous
Some create eggs which they retain & hatch inside body- ovoviviparous
Some males may have bursa- flap of skin used to hold female while transfering sperm
May also have copulatory spikes or spicules which are penis-like

12. Typical Nematode Life Cycle
Egg
L1- 1st larval stage
L2- 2nd larval stage
L3- 3rd larval stage
L4- 4th larval stage
Adult
Molt in between each larval stage to get bigger
Dauer- after 1st molt larvae may enter this hibernation stage if overpopulation pheromone is present, temperature is too high, or no food present.
Parasitic nematodes have different life cycles

13. VIII. Economic/Environmental Importance
Free-living soil nematodes & saprobes- important as recyclers of necessary nutrients to soil.
1 m2 of mud = 4 million nematodes!
b. Parasitic nematodes- Cause disease
Plants
Vertebrates
Humans

15. DAILY QUIZ #1 Nematodes are
a. Monoecious b. Dioecious
Nematodes are the first animals we have study to have
Nervous system b. Mouth and anus c. Excretory system
The structure that helps prevent digestion of parasitic nematodes is the
a. Cuticle b. Hook c. sucker
Which is true about nematodes
Males are larger than females
Females are larger than males
Neither A or B because they are hermaphrodites
Which is not a characteristic of nematodes?
Bilateral symmetry c. Pseudocoelom
Triploblastic d. Segmented
DAILY QUIZ #1