JOURNAL #1

1. JOURNAL #1 • KWL: What do you KNOW about segmented worms? What do you WANT to know about segmented worms? What have you LEARNED about segmented worms?

2. PHYLUM ANNELIDA

3. General Information • “annelid” means tiny rings • Coelomates- true body cavity w/space for true internal organs. • Body is cylindrical & metameric- segmented • Bilateral symmetry • Closed circulatory system • Most have paired setae for movement

4. II. Class Oligochaeta • Earthworms w/ few setae • Terrestrial or aquatic • Body Structure • 1. Prostomium- 1st body segment, overlaps mouth • 2. Pygidium- last body segment, overlaps anus • 3. Cuticle- tough outer covering for protection • 4. Muscles- 2 sets create wave-like motion; longitudinal & circular • 5. Clitellum- band-like structure at anterior end • 6. Setae- short bristles on ventral surface that help them cling to burrows, movement/anchoring

6. Digestion/Feeding • 1. Nocturnal- feed at night on leaf litter & soil (scavengers/decomposers) • 2. Mouth- opening to digestive tract • 3. Pharynx- acts like pump, pulling food into mouth. • 4. Esophagus- tube that leads to crop • 5. Crop- storage chamber for food. • 6. Gizzard- grinds food before it enters intestine. • 7. Intestine- absorbs nutrients from food- has folds called typhlosole that increase surface area to absorb more food. • 8. Anus- solid wastes excreted here • 9. Castings- squiggles of mud on soil surface “worm feces”

7. Intestine Gizzard Crop Esophagus Pharynx Ventral Nerve Cord

8. Excretory System • 1. Nephridia- kidney-like organ that consists of tubes for conducting liquid waste • One per segment • 2. Nephridiopores- pores in skin that excrete liquid waste. • Nervous System • 1. Cerebral ganglion- bi-lobed simple brain over pharynx • 2. Ventral Nerve Cord- runs length of body on ventral surface • ** Sensitive to touch, light, temp., moisture

9. E. Respiratory system • Gas exchange occurs thru diffusion thru moist skin

10. F. Circulatory System 1. Closed Circulatory System- blood is enclosed in blood vessels 2. 5 Pairs of Aortic Arches- enlarged blood vessels that pump blood thru body 3. Dorsal blood vessel- carries blood to anterior end 4. Ventral blood vessel- carries blood to posterior end

11. G. Reproductive System 1. Monoecious- hermaphrodites 2. Do not self-fertilize 3. Worms line up w/anterior ends away from each other. 4. Sperm released from seminal vesicles & is passed along a body groove to the seminal receptacles (receivers)

12. 5. Eggs are kept in oviducts until “ripe” 6. After 2-3 hours of copulation, clitellum forms sticky cocoon. 7. Cocoon passes down body, picking up egg & sperm 8. Fertilization occurs in the cocoon. 9. Cocoon is deposited in moist soil where it hatches after about 3 weeks.

13. Being a hermaphrodite is beneficial to simple animals because 1. Do not have to search out a specific mate… can mate with any worm that comes along. 2. Twice as many offspring can be produced because both can carry eggs.

14. Seminal Receptacles- receive sperm from mate Seminal Vesicles- store worms own sperm Cerebral ganglion 5 Aortic Arches Nephridia- 2 per segment for excretion Dorsal Blood Vessel

15. III. Class Hirudinea • Leeches with no setae • Most freshwater, some marine & terrestrial • Ectoparasites that feed on body fluid of host • Flattened, segmented • 34 segments

16. A. Digestion/Feeding • Anterior & posterior sucker for attachment to host • Jaws slice skin & begin sucking blood. • Secrete anesthetic- so you don’t feel bite. • Secrete anticoagulant- Hirudin- keeps blood from clotting while feeding. • Engorge until 10x normal size then drop off • Only need to eat every few months.

18. Respiratory/Circulatory/Nervous/Excretory • Same as earthworms • Reproductive System • 1. Monoecious- hermaphrodites • 2. Clitellum is only present during spring when leeches usually breed

19. IV. Class Polychaeta • Marine worms with many setae • 2. Largest class of annelids • 3. Live in coral reefs, ocean floor, crevices, etc • Have parapodia which look like paddles along body • Have sensory tentacles called cirri around mouth. • Reproductively- dioecious

20. V.Economic/Environmental Importance • recycle nutrients to soil. • burrows aerate & provide space for growing plant roots. • Leeches used for removing excess blood after surgery for reattachment of amputated limbs. Body heals faster. • Part of food chain

21. DAILY QUIZ #2 • The structure used for grinding food in the earthworm is the a. Crop b. Nephridia c. gizzard • Annelida means a. Soft skin b. Tiny rings c. Flat body • This phylum of worms is put into different classes based on • Method of reproduction b. Type/presence of setae c. Shape of body • The bristle-like structures that help earthworms move are called a. Setae b. Clitellums c. crops • Earthworms are • Monoecious b. Dioecious

22. Journal #5 • How are earthworms important to humans and the environment?

23. JOURNAL #4 • Explain two ways being a hermaphrodite is beneficial to the earthworm.

24. DAILY QUIZ • Before dissecting, it is necessary for you to • Put on a safety apron • Soak your specimen in preservative • Wash your specimen to remove preservative • The body covering of the earthworm is best described as a. Moist cuticle b. Hard exoskeleton c. Dry & bumpy • Leeches a. Secrete Hirudin b. Secrete anesthetic c. Both A and B • The paddle-like setae that are found on the sides of polychaetes like the clamworm is referred to as a. Polychaeta b. Parapodia c. oars • The band-like structure used for reproduction in the earthworm is the a. Cuticle b. Clitellum c. nephridia

25. DAILY QUIZ #4 2 4 1 • Gizzard d. Aortic arches • Crop e. Seminal vesicles • Nephridia f. Seminal receptacles 3 5

26. Journal #8 • Compare and contrast the digestive systems of the leech and earthworm.