The Worm by bsw17644

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									                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
1. Water: fresh and salty
  1. Aquatic worms swim
     1. Clam worms are predators
  2. Aquatic worms attach themselves
     permenantly to surfaces and build burrows
     1. Giant Tube Worms
2. Mud: worms burrow and crawl
3. Live hosts: parasitic worms
          Three Worm Phyla
1. 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
         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!
         Three Worm Phyla
2. 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
        Parasitic Roundworms
•   Hosts include plants, insects, animals,
    etc.
•   Examples
    1. Hookworms: Enter sole of foot, bloodstream,
       lungs, and coughed into stomach
    2. Trichinella: Live in muscles of mammals
       (pigs); Eggs may infect humans if eat
       undercooked pork
      1. Trichinosis: flu-like symptoms, although rare,
         there is a risk to heart and nervous tissues
         Three Worm Phyla
3. 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!
      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
Focus: Planaria
   Freshwater Planaria




                Land Planarian
 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
Focus: Earthworms
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!
                                   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=k94zWaTP
    74XozM:&tbnh=87&tbnw=116&prev=/images%3Fq%3Dworms%26svnum%3D10%26hl%3Den%26client%3Dfirefo
    x-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=e
    n&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=DPttxZSM
    9JMCIM:&tbnh=118&tbnw=92&prev=/images%3Fq%3Dplanaria%26svnum%3D10%26hl%3Den%26client%3Dfire
    fox-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://w
    ww.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=Ks5vrHULcytAQ
    M:&tbnh=77&tbnw=122&prev=/images%3Fq%3Dgiant%2Btube%2Bworms%26svnum%3D10%26hl%3Den%26cli
    ent%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.if
    remer.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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