Body Cavity Present Have a true coelom, a body cavity completely lined by tissue derived from mesoderm
Body Symmetry bilateral symmetryhttp://www.sheppardsoft ware.com/content/ani mals/images/clipart_e arthworm.jpg
Nervous System A brain-like pair of cerebral ganglia above and in front of the pharynx A ring of nerves around the pharynx that connects to a subpharyngeal ganglion, from which a fused pair of nerve cords runs posteriorly.
Circulatory System Have a closed circulatory system 5 pairs of hearts Blood vessels circle esophagus and pump blood
Digestive System Unsegmented digestive tract Mouth Pharynx Esophagus Crop Gizzard Intestine Anus
Excetory System Annelida have excretory organs called nephridia, directly remove waste from the bloodstream In earthworms (class Oligochaeta), waste is used to fertilize the soil
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 move Polychaetes have parapodia (almost feet) to move, and polychaetes and leeches can swim
Skeletal Type None, their bodies are composed a a series of fused segments with muscles
Sensory structure/features Have tactile organs (touch), taste buds, photoreceptor cells, and some have eyes with lenses Palps and antennae are located on the head (tactile) Also have lateral organs- epidermal sensory cells that are responsive to light or touch
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.
Gas Exchange Earthworms have many tiny blood vessels in their skins, which function as their respiratory organs The blood has hemoglobin that carries oxegen. In leeches, most gas exchange occurs through the body wall
Unique Characteristics Easily recognized due to segmented bodies Most segments have the same internal structures repeated throughout the worm Leeches used to be used for blood letting, and today are used to drain blood that accumulates in tissues after injuries or surgeries
QUESTION #1 1.What type of body cavity do annelids have? a.Coalomate b.Pseudocoelomate c.Acoelomate d.none
Answer A. COELOMATE
QUESTION #2 An annelids circulatory system includes how many pairs of hearts? a.6 b.9 c.1 d.5
ANSWER D. 5
QUESTION #3 Describe the skeletal type of annelids. a.They have an exoskeleton. b.The do not have one. c.They have a cuticle d.They have a hydrostatic skeleton.
ANSWER B. They do not have one
QUESTION #4 How do earthworms exchange gas? a.Diffusion b.They do not. c.They have many tiny blood vessels in their skins, which function as their respiratory organs
ANSWER C They have many tiny blood vessels in their skins, which function as their respiratory organs