Transcript PHYLUM PLATYHELMINTHES – The Flatworms

Radiata
Parazoa
no true tissues
Bilateria
Eumetazoa
Multicellularity
1.
2.
3.
4.
5.
What is the literal meaning of
Platyhelminthes?
A muscular tube used to suck food into the
gastrovascular cavity.
Platyhelminthes depend on what process to
respire?
What is the term used to describe the three
germ layers?
True or False: Platyhelminthes can be
parasitic.
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with tissues
 organ
systems
triploblastic
bilaterallysymmetric
with
cephalization
acoelomates
Pseudocerus sapphirinus
Pseudobiceros bedfordi
Acanthozoon sp.
Phrikoceros sp.
Marine flatworms of the Philippines
from http://www.rzuser.uni-heidelberg.de/
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carnivores or
detritivores
incomplete
digestive
system
 highly-
branched
GVC
 pharynx

external 
internal
digestion,
diffusion
http://www.southtexascollege.edu/nilsson/4_GB_L
ecture_figs_f/4_GB_23_AnimaliaInvert_Fig_f/Plat
yhelminthes_Planaria_2.GIF
feed on blood,
tissue fluids, pieces
of cells within host
 no need for
complex digestive
system
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 Clonorchis sinensis
(human liver fluke)
 Taenia saginata
(beef tapeworm)
http://www.esu.edu/~milewski/intro_biol_two/lab__10_platy_nemat/images/clonorchis.jpg,
http://www.microbeworld.org/images/stories/twip/clonorchis_lifecycle.jpg
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diffusion
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flame cells remove
nitrogenous
metabolic wastes
and excess H2O
http://faculty.uca.edu/johnc/PlanarianPronephr.gif
 ganglia
 nerve cords
(ladder-like)
 eyespots
 sensory cells
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
Muscles
Ventral epidermal cilia + mucus
http://mlitvaitis.unh.edu/K-12Primer/muscles.jpg
FREE-LIVING
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FISSION AND REGENERATION
HERMAPHRODITISM AND CROSS-FERTILIZATION
http://images.tutorvista.com/content/reproduction/fragmentation-in-planaria.jpeg, http://users.design.ucla.edu/~tatsuyas/classes/152BC/ex3/planaria.jpg,
http://www.visualdiving.com/pics/uw962_35.jpg
PARASITIC
COMPLEX LIFE CYCLES
WITH BOTH ASEXUAL
AND SEXUAL
REPRODUCTION
(Schistosoma japonicum)
http://siera104.com/images/bio/flatroundrotifer
s/shistomsoma.jpg
Phylum
Platyhelminthes
Class Turbellaria
Class Trematoda
Class Cestoda
flukes
Tapeworms
free-living
flatworms
Taenia
Dugesia
Schistosoma
Diphyllobothrium
http://www.e-cleansing.com/wp-content/uploads/2009/12/laiuss1.jpg
Long, flat, parasitic worms
 Structure
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 Scolex: head w/ suckers,
hooks
 Proglottids: body segments
that produce both sperm and
egg
http://www.ohiohealth.com, http://www.marlin.ac.uk/images/taxonomy_descriptions/Cestoda.jpg
http://www.dpd.cdc.gov/dpdx/images/ParasiteImages/SZ/Taeniasis/Taenia_LifeCycle.gif
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with tissues  organ
systems
“tube within a tube”
triploblastic
bilaterally-symmetric
with cephalization
pseudocoelomates
http://mycozynook.com/18_3bodyplanp.jpg , http://sharon-taxonomy2009p2.wikispaces.com/file/view/nematode.gif/99304909/nematode.gif
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carnivores/ detritivores or parasites
complete digestive system
internal digestion, diffusion
http://images.tutorvista.com/content/animalkingdom/roundworm-anatomy.jpeg
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diffusion through epidermis and cuticle
with an excretory canal and pore
http://images.tutorvista.com/content/animalkingdom/roundworm-anatomy.jpeg
 circular nerve ring  primitive brain
 dorsal and ventral nerve cords
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muscles
hydrostatic skeleton
http://www.baileybio.com/plogger/images/ap_biology/animal_diversity_project_-_must_cite_your_textbook_/nematoda_2.jpg
SEXUAL: INTERNAL
FERTILIZATION
ASEXUAL:
PARTHENOGENESIS

unfertilized egg
develops into an
adult organism
without sperm
fertilization
http://sharonapbiotaxonomy.wikispaces.com/file/view/nematode.jpg/5086
4359/nematode.jpg, http://www.mansfield.ohiostate.edu/~sabedon/black11_files/image023.jpg
PARASITIC
COMPLEX LIFE CYCLES
(Trichinella spiralis)
http://siera104.com/images/bio/flatroundrotifer
s/shistomsoma.jpg
PARASITIC
COMPLEX LIFE CYCLES
Filarial worms
(Brugia malayi)
threadlike
blood and lymph vessels
of birds and mammals
• vector: biting insects
• with symbiotic bacteria
Wolbachia
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PARASITIC
COMPLEX LIFE
CYCLES
Ascaris spp.
•
causes malnutrition
in >1B people
http://www.metapathogen.com/IMG/ascaris-life-cycle.png
PARASITIC
COMPLEX LIFE
CYCLES
Hookworms
•
Infects ~1/4 of the
world’s population