Annelids
KingdomAnimal
PhylumPlatyhelminths
(Flatworms)
PhylumNematoda
(Roundworms)
PhylumPoriferaSponges
Segmented worms!
PhylumAnnelida
(Segmented worms)
Segmented WormsKingdomAnimal
PhylumAnnelida
(Segmented Worms)
ClassHirundinea(Leeches)
ClassOligochaeta
(Earthworms +)
ClassPolychaeta
(Marine Worms)
Earthworms(Class Oligochaeta)
• Each body segment has four pairs of setae• Two sets of muscles for movement
– Round muscles – Long muscles
• Well developed digestive system• Closed circulatory system• Small Brain• Hermaphrodites
Digestive System
• Mouth• Pharynx (Throat)-muscular for food intake• Esophagus-tube which takes food to crop• Crop- Sac used for food storage• Gizzard- muscular structure that grinds soil and
organic matter• Intestine - absorbs nutrients moving them into the
blood• Anus - wastes are excreted• Nephridia- help filter waste out of blood
Circulation and Respiration
• Closed circulatory system-moves blood through vessles
• Aortic arches-- heartlike structure that pumps blood thru earthworms body.
• Dorsal blood vessel on top Ventral blood vessel on bottom
• Oxygen and carbon dioxide is exchanged through the skin.
Nervous System
• Small brain or ganglia is made up of a mass of nerve tissue
• Nerves in each segment join to form a main nerve cord that connects to the brain
Reproductive System
• Hermaphrodites
• Cannot fertilize their own eggs
• Seminal Vesicles- location of sperm production
• Seminal Receptacle-where sperm is received during copulation
Other Parts
• Clitellum- swelled gland 1/3 of the way down the earthworm that releases material for earthworm cocoons
Earthworm Benefits
• Help recycle nutrients in the soil
• Help aerate the soil ( move estimated 36000 pounds per acre of soil each year)
• Food source for other animals
LeechesKingdomAnimal
PhylumAnnelida
(Segmented Worms)
ClassHirundinea(Leeches)
ClassOligochaeta
(Earthworms +)
ClassPolychaeta
(Polychaetes)
Leech Facts
• Feed on blood of other animals
• Use anesthetic, so you do not feel the bite
• Can suck 2-10 times it’s own weight in blood