Transcript Annelida
Annelida By: Kiran Basava Isabelle Nievera http://folkworm.ceri.memphis.edu/ew-doc/GIFS/ew.logo.gif Annelida • Means “little rings” which resembles the annelids body, which is a series of fused rings. • Live in the sea, freshwater habitats, and damp soil. http://www.botswanagallery.org/thesis/A/img2/earthworms.jpg Classes http://www.freewebs.com/invertebratezoology/Earthworm1.jpg Oligochaetea (earthworms) http://marinediscovery.arizona.edu/alex%20tuttle%20webpage/fireworm.jpg Polychaeta http://itsmeela.files.wordpress.com/2007/07/450px-leech_blutegel.jpg Hirudinea (Leeches) Body Cavity • Present • Have a true coelom, a body cavity completely lined by tissue derived from mesoderm http://www.glogster.com/media/2/3/92/77/3927715.jpg Body Symmetry • bilateral symmetry http://www.sheppardsoft ware.com/content/ani mals/images/clipart_e arthworm.jpg http://www.sheppardsoftware.com/content/animals/images/clipart_earthworm.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. http://media-2.web.britannica.com/eb-media/37/73337-004-B0D75E62.jpg Circulatory System • Have a closed circulatory system • 5 pairs of hearts • Blood vessels circle esophagus and pump blood http://infusion.allconet.org/webquest/img010.jpg Digestive System • Unsegmented digestive tract • Mouth Pharynx Esophagus Crop Gizzard Intestine Anus http://yhsbiology.wikispaces.com/file/view/digest.jpg/49088317/digest.jpg 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 http://image.tutorvista.com/content/excretion-and-osmoregulation/septal-nephridia-illustration.jpeg 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 http://mfaucher.com/files/Uganda03/675dpi/ug14_25.jpg Skeletal Type • None, their bodies are composed a a series of fused segments with muscles http://www.teachyourselves.co.uk/worm.jpg 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 organsepidermal sensory cells that are responsive to light or touch http://tolweb.org/onlinecontributors/app?service=external/ViewImageData&sp=3990 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. http://www.offthemarkcartoons.com/cartoons/2005-11-11.gif 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 annelid’s 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