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The Worm

The Worm. A Sophisticated Yet Small Invertebrate. Characteristics of Worms. Invertebrates Bilateral Symmetry Definite head where nerve and sense organs are concentrated Complex tissues: develops from 3 different tissue types including mesoderm (muscle). Habitats of Worms.

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The Worm

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  1. The Worm A Sophisticated Yet Small Invertebrate

  2. Characteristics of Worms • Invertebrates • Bilateral Symmetry • Definite head where nerve and sense organs are concentrated • Complex tissues: develops from 3 different tissue types including mesoderm (muscle)

  3. Habitats of Worms • Water: fresh and salty • Aquatic worms swim • Clam worms are predators • Aquatic worms attach themselves permenantly to surfaces and build burrows • Giant Tube Worms • Mud: worms burrow and crawl • Live hosts: parasitic worms

  4. Three Worm Phyla • Flatworms, Platyhelminthes • Flattened body shape, simplest worm • Developed organs and organ systems • Digestive cavity with one opening • Free living (planaria) or parasitic (flukes and tapeworms) • Hermaphroditic but cannot fertilize own eggs

  5. Parasitic Flatworms • Flukes live in body tissues of animals making them sick • Tapeworms live in intestines of animals • No digestive cavity! Absorbs nutrients directly from host. • Reproduction: pieces of worm break off and end up in host waste; if ingested by another animal, the eggs hatch in the new host • Don’t eat poop! WASH YOUR HANDS!

  6. Three Worm Phyla • Roundworms, Nematoda • Rounded body shape • Tiny, but visible to human eye • “tube within a tube”: 1-way digestive tract with a separate mouth and anus • Reproduction: sexual with separate male and female worms which produce 200,000 eggs per day! • Free living and Parasitic worms

  7. Parasitic Roundworms • Hosts include plants, insects, animals, etc. • Examples • Hookworms: Enter sole of foot, bloodstream, lungs, and coughed into stomach • Trichinella: Live in muscles of mammals (pigs); Eggs may infect humans if eat undercooked pork • Trichinosis: flu-like symptoms, although rare, there is a risk to heart and nervous tissues

  8. Three Worm Phyla • Segmented Worms, Annelida • Body divided into small units or segments • Fluid-filled body cavity called a coelom • Coelom holds organs and supports them with “water skeleton” • Regeneration occurs in many species • Reproduction: Both male and female organs but require a mate; Secretes cocoon (egg case) with eggs and another worms’ sperm; Embryonic worms develop until emerging from cocoon as fully formed worms!

  9. Focus: Planaria Flatworms • Free living, freshwater worms; 2.5 cm long • Eyespots on top of head sense light/dark! • Food enters mouth (opposite end of head) • Sexual and asexual reproduction • Planaria can divide in half and regenerate two new worms! • Nerve cells form simple brain in head… • Learning studies with planaria

  10. Focus: Planaria Freshwater Planaria Land Planarian

  11. Focus: Earthworms (Annelida) • Brain, nerve cord, and 5 hearts! • Stiff bristles on segments aid movement • Digestive organs: crop, gizzard, and intestine • Grind up soil and remove organic material • Leave behind inorganics important to plants such as nitrates and phosphates (casts) • Aerate and mix soil, allow water to enter • Eats and discards it’s weight in soil each day

  12. Focus: Earthworms

  13. Focus: Giant Tube Worms • Phylum: Annelida • Habitat: Hydrothermal vents • Symbiosis with bacteria • Worm can retract into protective tube; Up to 8 feet high • No mouth or digestive tract!

  14. Works Cited • Title image: http://images.google.com/imgres?imgurl=http://safari.zog.org/images/20040819_162616_DSC6089-thumb.jpg&imgrefurl=http://safari.zog.org/en/worms.cfm&h=225&w=300&sz=82&hl=en&start=7&tbnid=k94zWaTP74XozM:&tbnh=87&tbnw=116&prev=/images%3Fq%3Dworms%26svnum%3D10%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DN • Land Planaria: http://images.google.com/imgres?imgurl=http://entweb.clemson.edu/cuentres/eiis/factshot/images/landplanaria.jpg&imgrefurl=http://entweb.clemson.edu/cuentres/eiis/factshot/pages/LandPlanaria.htm&h=186&w=360&sz=12&hl=en&start=3&tbnid=ustyGncWwgZ-wM:&tbnh=63&tbnw=121&prev=/images%3Fq%3Dplanaria%26svnum%3D10%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG • Planaria: http://images.google.com/imgres?imgurl=http://www.ru.ac.za/institutes/iwr/ucewq/pix/planaria.jpg&imgrefurl=http://www.ru.ac.za/institutes/iwr/ucewq/cultures.html&h=337&w=450&sz=12&hl=en&start=1&tbnid=I9OPlkTTW-iwfM:&tbnh=95&tbnw=127&prev=/images%3Fq%3Dplanaria%26svnum%3D10%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG • Planaria (green): http://images.google.com/imgres?imgurl=http://centros.edu.xunta.es/iesaslagoas/slorenf/planaria06.jpg&imgrefurl=http://centros.edu.xunta.es/iesaslagoas/slorenf/ins48.htm&h=319&w=249&sz=15&hl=en&start=5&tbnid=DPttxZSM9JMCIM:&tbnh=118&tbnw=92&prev=/images%3Fq%3Dplanaria%26svnum%3D10%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG • Planaria diagram: http://centros.edu.xunta.es/iesaslagoas/slorenf/planaria06.jpg • Earthwrom: http://images.google.com/imgres?imgurl=http://www.kidcyber.com.au/IMAGES/earthworms.jpg&imgrefurl=http://www.kidcyber.com.au/topics/worms.htm&h=169&w=227&sz=7&hl=en&start=1&tbnid=CrpKbLzVpcFawM:&tbnh=80&tbnw=108&prev=/images%3Fq%3Dearthworms%26svnum%3D10%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG • Anatomy: http://io.uwinnipeg.ca/~simmons/16cm05/1116/33-23-EarthwormAnatomy-L.jpg • Tube worms: http://images.google.com/imgres?imgurl=http://library.thinkquest.org/18828/media/giant_tubeworms.jpg&imgrefurl=http://library.thinkquest.org/18828/data/fn_3.html&h=231&w=367&sz=22&hl=en&start=6&tbnid=Ks5vrHULcytAQM:&tbnh=77&tbnw=122&prev=/images%3Fq%3Dgiant%2Btube%2Bworms%26svnum%3D10%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG • Vents: http://images.google.com/imgres?imgurl=http://www.ifremer.fr/2ishvb/images/ouverture.jpg&imgrefurl=http://www.ifremer.fr/2ishvb/france.htm&h=394&w=425&sz=134&hl=en&start=5&tbnid=FFGaDBMSW3nFNM:&tbnh=117&tbnw=126&prev=/images%3Fq%3Dhydrothermal%2Bvents%26svnum%3D10%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG

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