6 Nervous SystemA brain-like pair of cerebral ganglia above and in front of the pharynxA ring of nerves around the pharynx that connects to a subpharyngeal ganglion, from which a fused pair of nerve cords runs posteriorly.
7 Circulatory System Have a closed circulatory system 5 pairs of hearts Blood vessels circle esophagus and pump blood
8 Digestive System Unsegmented digestive tract Mouth Pharynx Esophagus Crop Gizzard Intestine Anus
9 Excetory SystemAnnelida have excretory organs called nephridia, directly remove waste from the bloodstreamIn earthworms (class Oligochaeta), waste is used to fertilize the soil
10 Locomotion/Musculature Each segment of an earthworm is surrounded by a longitudinal muscle that coordinates with a surrounding circular muscle to allow an earthworm to movePolychaetes have parapodia (“almost feet”) to move, and polychaetes and leeches can swim
11 Skeletal TypeNone, their bodies are composed a a series of fused segments with muscles
12 Sensory structure/features Have tactile organs (touch), taste buds, photoreceptor cells, and some have eyes with lensesPalps and antennae are located on the head (tactile)Also have lateral organs- epidermal sensory cells that are responsive to light or touch
13 Reproduction Hermaphrodites Cross fertilize by aligning to exchange sperm, which is stored while an organ called the clitellum makes a cocoon that receives the eggs and sperm from the worm, and remains in the soil while embryos develop.
14 Gas ExchangeEarthworms have many tiny blood vessels in their skins, which function as their respiratory organsThe blood has hemoglobin that carries oxegen.In leeches, most gas exchange occurs through the body wall
15 Unique Characteristics Easily recognized due to segmented bodiesMost segments have the same internal structures repeated throughout the wormLeeches used to be used for blood letting, and today are used to drain blood that accumulates in tissues after injuries or surgeries
16 QUESTION #1 What type of body cavity do annelids have? Coalomate PseudocoelomateAcoelomatenone
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