Transcript Annelida
http://surferjerry.com/wp-content/uploads/2009/02/giant-south-african-earthworm.png ANNELIDA By Emily Chu and Wonhyoung Kim Segmented worms CLASSES Oligochaeta (earthworms and relatives) Polychaeta (polychaetes) Hirudinea (leeches) Leech Earthworm http://www.cheshirewildlifetrust.co.uk/IMA GES/watch_earthworm.jpg Christmas tree worm http://www.microteufel.com/TripReports/M aui/Aquarium/IMG_0063s.jpg http://www.io.com/~dierdorf/leech.jpg BODY CAVITY (COELOM) Present Annelida=coelomate (has a true coelom) http://biology.unm.edu/ccouncil/Biology_203/Images/SimpleAnimals/Coelomate.JPG BODY SYMMETRY Bilateral symmetry http://www.mun.ca/biology/scarr/142003_Annelida.jpg NERVOUS SYSTEM Have brain-like pair of cerebral ganglia Ventral nerve cords with segmental ganglia (runs through length of body) CIRCULATORY SYSTEM Closed circulatory system—blood contained within vessels Blood contains oxygen-carrying hemoglobin DIGESTIVE SYSTEM Earthworms eat through the soil, extracting nutrients as the soil passes through the alimentary canal. Have digestive tract http://johnson.emcs.net/life/images/earthworm.jpg EXCRETORY SYSTEM Metanephridium=excretory tubes Remove waste from the blood and coelomic fluid through exterior pores Nephrostomes=ciliated funnels LOCOMOTION/MUSCULATURE Chaetae=bristles that provide traction for burrowing Each segment is surrounded by a longitudinal muscle, which is in turn surrounded by circular muscle. Contractions of these muscles allow for movement. http://oceanexplorer.noaa.gov/explorations/03windows/logs /jul28/media/naut_allseate_600.jpg SKELETAL TYPE No true skeleton Hydrostatic skeleton—controlled by coelomic fluid SENSORY STRUCTURES/FEATURES Simple sensory structures Single-celled structures detect light, chemicals, pressure waves, and contact Some polychaetes have ocelli (“little eyes”) REPRODUCTION Hermaphrodites Earthworms cross-fertilize Two earthworms exchange sperm then separate Received sperm are stored temporarily while the clitellum secretes a mucous cocoon Cocoon slides along the worm, picking up eggs and then the stored sperm Some earthworms can also reproduce asexually by fragmentation followed by regeneration Clitellum http://static.howstuffworks.com/gif/willow/earthworm-info0.gif GAS EXCHANGE SKIN! This is the respiratory organ. Hemoglobin in blood carries oxygen Some polychaetes have gills http://upload.wikimedia.org/wikipedia/commons/e/ea/Christmas_tree_worms.jpg OTHER UNIQUE FEATURES Today, leeches are used to drain blood that accumulate in tissues following certain injuries. Leeches secrete hirudin (prevents blood from clotting, which allows leech to feed) Hirudin has the potential to be used in the future to dissolve blood clots that form during surgery or as a result of heart disease. THE END!!!! Just kidding… http://www.breaktaker.com/albums/pictures/animals/LaughingCat.jpg QUIZ TIME! 1. What is the primary respiratory organ? 2. Describe the annelid’s circulatory system. 3. Give two examples of methods of reproduction and explain each. 4. Which of these phyla consists of species with a coelom? A. B. C. D. Porifera Cnidaria Annelida Platyhelminthes CHECK YOUR ANSWERS! 1. The skin 2. Closed circulatory system 3. Sexual—two hermaphroditic annelids align and exchange spermclitellum secretes cocoon Asexual—fragmentation and regeneration 4. C. Annelida