Earthworms have a complete digestive tract with a mouth, pharynx, esophagus, crop, gizzard, intestine and anus. They have a closed circulatory system with a dorsal blood vessel, five pairs of aortic arches that pump blood, and a ventral blood vessel. Their respiratory, excretory, and nervous systems are also simple. Earthworms are hermaphrodites, with a clitellum that secretes mucus during reproduction to allow sperm transfer between worms and development of young inside a protective tube.

1. Earthworms - Nature’s
Plowman
By Dwayne Vaz

2. Characteristics of
earthworms
●Bilateral symmetry
●Well developed coelom (body cavity)
●Setae (bristles on belly for locomotion)
●Longitudinal muscles (long & short)
●Circular muscles (thick & thin)
Bilateral Radial

3. I. Digestive System - complete digestive tract
●Mouth - entrance for food
●Pharynx - sucks in and pumps food & soil
●Esophagus - passage for food
●Crop - stores food
●Gizzard - grinds food
●Intestine - digests food
●Anus - exit of undigested food

4. II. Circulatory System - closed circulatory system
●Dorsal blood vessel - conducts blood to head
(anterior end)
●Aortic arches/hearts (5 pairs)- pumps blood
●Ventral blood vessel - conduct blood to the tail
(posterior end)

5. III. Respiratory system
●Diffusion through moist skin & oxygen
travels in the blood

6. IV. Excretory system
●Pair of nephridia in each segment to rid
body of cell waste

7. V. Nervous System - simple brain &
ventral nerve cord
●Brain - processes infromation
●Ganglion - carry impulses
●Ventral nerve cord - connect ganglia
together

8. VI. Reproductive system - is hermaphroditic
(both male & female)
●Clitellum secretes mucus to bind 2 worms
●Sperm from seminal vesicles travel through
mucus
●Sperm enter seminal receptacles of other
worm
●Clitellum secretes a tube & egg & sperm
enter tube, fertilize, & young develop in case

9. Reproduction

10. THANK YOU