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Earthworms. What is an Annelid?. Latin annellus means “little ring”. Annelids are ringed or segmented worms. . Earthworm Facts. Except for the first and last segments, all body segments have the same sets of organs. . Earthworm Facts. Septa separate one segment from the other.
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What is an Annelid? Latin annellus means “little ring”. Annelids are ringed or segmented worms.
Earthworm Facts Except for the first and last segments, all body segments have the same sets of organs.
Earthworm Facts Septa separate one segment from the other.
Earthworm Facts Setae are bristles attached to each segment used to help with movement.
Earthworm Facts - Skin • They do not have lungs. • They breathe through their moist skin. If their skin dries out, they will die. • They do not have eyes • They use light sensitive skin cells to sense light.
Earthworm Facts – Digestive System Earthworms obtain food by extending their mucus covered pharynx Food is then pumped into the esophagus Food moves to the crop where it can be stored until… it is moved into the gizzard where it is ground into smaller pieces finally the food is absorbed in the intestine
Earthworm Facts – Circulatory System • Earth worms have a closed circulatory system - blood stays in blood vessels.
Earthworm Facts – Circulatory System • Aortic arches – Act as hearts; providing pulsation for blood
Earthworm Facts – Circulatory System Earthworms have 2 major blood vessels that run from head to tail. Dorsal blood vessel - (on the worm’s back) carries blood from the tail to the head Ventral blood vessel - ( on worm’s belly) carries blood from head to tail
Earthworm Facts - Excretion Digestive waste passes through the anus. Cellular waste is filtered our through the nephridia.
Earthworm Facts – Reproductive System Earthworms contain both male and female reproductive organs, but they do not self fertilize. Seminal Vesicles Produce Sperm Ovaries Produce Eggs Seminal Receptacles Store sperm after mating
Earthworm Facts - Clitellum This is the band of thickened segments towards the head of the worm.
Earthworm Facts - Clitellum When eggs are ready to be fertilized the clitellum produces a thick mucus ring. Eggs and sperm are released into this mucus ring, which is detached and becomes and egg case.
Identifying Structures Describe the function of each structure.