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

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

Phylum Nematoda

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

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

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.

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

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

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

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

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

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

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