Transcript Flatworms and Ribbon Worms

Flatworms and Ribbon Worms
By: Paige Harris
Flatworms
• Flat body
• Both freshwater
and saltwater species
• Some are microscopic
and some can get up
to 20 meters long
• More than 10,000
species
Flatworms cont.
• Live at the bottom of
the water column
• Reproduces by splitting
in two, immediately forming
a new worm
• They are free living or
parasitic
• http://www.youtube.com/watch?v=ET1v9-65Jwk
Planarian
• Found in freshwater
and marine habitats
• Have a two-way digestive
tract
-food enters mouth  digested in
intestine
-nutrients diffuse throughout
the body
-undigested materials discharged
form the mouth
• No circulatory or respiratory
systems
• Have both male and female
reproductive systems, like most
flatworms
Planarian cont.
• Glide along ocean bottom, moving its head from side to side by:
-contracting body muscles and the action of cilia which are
attached to the cells of the ventral side
• Contain ganglia which act like a simple brain
-send nerve impulses along two ventral nerve cords to the rest of
the body
• Bilateral symmetry: both sides of its body have the same structures
• They have three cell layers:
-ectoderm
-endoderm
-mesoderm
• http://www.youtube.com/watch?v=Fq_aSR5FK0Y
Reproduction
• Asexual
-it attaches to a substrate
-stretches its body
-breaks into two
• Sexual
-can produce on their own because they contain both
reproductive systems in each body
Tapeworm
• Sometimes found in intestines of fish and other animals,
including humans
• Attaches itself to the lining of its host and absorbs
nutrients directly through its thin body wall
• Can grow to be 18 meters in length
Liver Fluke
• AKA: Trematode
• Lives in bodies of mollusks, fish, birds, and other
animals
• They can attach to your body if they are looking
for a host while you are swimming in the water
• This is called swimmer’s itch
Life Cycle
of
Liver Flukes
Ribbon Worms
•
•
•
•
Largest free living worm in the sea
1000 species
Classified in the phylum Nemertea
Live in the intertidal zone
-in sand or mud; or under rocks or shells
• Few are from freshwater and terrestrial
habitats
Characteristics of Ribbon Worms
1)Bilaterally symmetrical and dorsoventrally flattened.
2)Body has more than two layers of cells with tissues and
organs.
3)Body has a through gut with a mouth and anus.
4)Body has no body cavity.
5)Has a blood system with blood vessels.
6)Has a well developed nervous system and a brain.
7)Has an eversible and retractable ectodermic proboscis.
8)Reproduction is by asexual fragmentation, or sexual,
when it is normally gonochoristic.
9)Most species are carnivorous and predatory.
10)Most are aquatic and marine, there are some terrestrial
and freshwater forms.
Citations
•
•
•
•
•
•
The Phylum Nemertea. Mr. Gordon Ramel. September 29, 2009. Earth-Life Web
Productions. March, 16 2009 <http://www.earthlife.net/inverts/nemertea.html>
Liver Fluke. March 15, 2009 <http://sprojects.mmi.mcgill.ca/tropmed/disease/intestlivfluke/life.htm>
Flatworms, including "Planaria" & Marine Aquariums, Part 1. Bob Fenner. Custom
Aquatic and Quality Marine. March 15, 2009
<http://www.wetwebmedia.com/flatworms.htm>
The History of the Universe, Humankind and Communism. Ben Seattle. August 22, 2002.
March 15, 2009
<http://images.google.com/imgres?imgurl=http://struggle.net/history/images/flatworm.gif
&imgrefurl=http://struggle.net/history/index.htm&usg=__RemG79c9yZTM8ohtlc594azhe6
k=&h=259&w=279&sz=27&hl=en&start=8&tbnid=rBPO550rWOqmNM:&tbnh=106&tbnw
=114&prev=/images%3Fq%3Dflatworms%26gbv%3D2%26hl%3Den>
Flatworms. March 15, 2009 <http://www.biologycorner.com/bio1/notes_flatworms.html>
Anatomy of Animals. March 15, 2009
<http://images.google.com/imgres?imgurl=http://universe-review.ca/I10-82planarian.jpg&imgrefurl=http://universe-review.ca/R10-33anatomy.htm&usg=__ullqmGjGYJeARPsHGWvsAOyNNCE=&h=581&w=327&sz=55&hl=
en&start=3&tbnid=O8Qb_SZUKfoulM:&tbnh=134&tbnw=75&prev=/images%3Fq%3Dpla
narian%26gbv%3D2%26hl%3Den>