Transcript Phylum Platyhelminthes

**Read the article about becoming an
1.
2.
3.
4.
5.
Oceanographer
What does an oceanographer do?
What advice does he give to students that
want to become oceanographers?
What does he do at work?
What happened on one dive in ALVIN?
Would you like to be an oceanographer?
Why or why not?
 Read
pages 516-518
–Answer questions 1 & 2 in
complete sentences!!
1.
2.
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4.
5.
Sponges are in the phylum _________.
Sponges are made up of ______ only.
Coral, jellyfish, and sea anemones are
in the phylum ________.
Cnidarians contain two tissue layers =
_________ & _________.
The jelly-like middle layer is called the
_________.
Kingdom: Animalia
Phylum Platyhelminthes
Flatworms
Plat and flat…they
rhyme
General Characteristics
 Bilateral
symmetry, front, back,
head, tail
 Only one body opening
 No body cavity
–Acoelomate: a = no
coelom = cavity or space
 Have
tissues and systems
–simple muscle and nervous
system
–Tissues: ectoderm—outer layer
(skin)
• Mesoderm—middle layer
(muscle)
• Endoderm—inner layer
(gut)
Reproduction
 Sexual
–Hermaphrodites (cannot selffertilize…exchange sperm)
 Asexual
–budding
Three classes
1. Turbellaria—nonparasitic
 Example:
Planaria
 No circulatory or respiratory
system
 Excretory system
–Flame cells help move along
wastes in excretory canals to
the excretory pores
 Eye
spots..sense light
 Eat using a tube called a pharynx
(like a vacuum hose)
 Nervous system
–Ganglion (bundles of sensory
receptors)
Planaria can learn!
Their memory, such as how
to find their way through a
maze, is stored chemically.
Planaria can learn!
One planarian can learn to
pass through a maze by
eating another one that
already knows the way!!!!!
2. Cestoda—parasitic
 Tapeworms
–Can be over 1 meter long
–Can get them by eating
uncooked infected beef
–They attach to the intestine
with sucker mouths
3. Trematoda--parasitic
 Flukes
 complex
life-cycle that involves
more than one host
 Latch on and ingests a host’s cells
and body fluids
 Blood Schistosoma—swelling,
ulcers, liver damage (from poor
sanitation, unwashed hands)
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2.
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4.
What are the three classes of
flatworms?
A flatworm does not have a body cavity
so we call it an ________________
What is a parasite?
Flatworms have tissues and ______.
Kingdom Animalia
Phylum Nemotoda
Roundworms
Think..long o sound - round
Common Characteristics
 Pseudocoelom—false
body
cavity…body cavity not
completely surrounded by
mesoderm
–Fluid filled body cavity
 First
group to have a mouth and
an anus!!!
 2 separate sexes = sexual
reproduction
There are more than a
million in a shovel-full
of topsoil!!
Ascaris
 Get
it from food or drink
contaminated with the eggs
 The roundworms grow in the
small intestine and cause
intestinal blockage…OUCH!
Filariae
 Spread
by mosquitoes
 Invade the lymphatic system
(moves fluid) and blocks lymph
vessels
 Causes swelling…elephantiasis
–Page 529
 Hookworm..pinworm—fecal
contamination
 Trichina worm—uncooked pork
(Trichinosis)
 Heartworm—
problem
with animals