Transcript Cnidaria - Net Start Class

Cnidaria
Daniel Lee
Matt Reynolds
Hussain Parbtani
Period 5
General Characteristics
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Live in exclusively aquatic or marine environments
Unique feature of cnidocyte (exclusive to cnidarians)
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Located on epidermis, usually on the tentacles of the cnidarian
Contains cnidea in the form of nematocysts, spirocysts, or ptychocysts
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Nematocysts – capsules of coiled threads and barbs (stylets). When
discharged deliver a venom to paralyze victim so it can be ingested
Spirocysts – found in corals/anemones. Sticky threads to help cnidarian
capture and stick to prey’s surface
Ptychocysts – usually found in bottom dwellers. Injected to help establish a
firm hold
Hollow sac-like body. Either vase shaped (polyp) or bell shaped
(medusa)
Cells specialized into tissues
One body opening (gastrovascular cavity)
Tentacles
Mucus secreting cells give the cnidarian a slimy characteristic
Class - Anthozoa
Coral
Works cited: http://en.wikipedia.org/wiki/Coral
Class - Cubozoa
Box Jellyfish
Works cited: http://worldofthestrange.co.uk/blog/media/1/box-jellyfish-22916-sw.jpg
Class - Hydrozoa
Hydra
Works cited: http://en.wikipedia.org/wiki/Hydra_(genus)
Works cited: http://www.animalpicturesarchive.com/ArchOLD-7/1192670344.jpg
Class - Scyphozoa
True Jellyfish
Body Plan
• Cnidarians are the simplest organisms that
have attained a tissue level of organization.
• They consist of layers with an epidermis, an
inner gastrodermis, and a non-cellular mesoglea
between the two.
• The mouth/anus serves as the entrance and
exit to and from the gastrovascular cavity.
• Cnidarians are radially symmetrical, meaning
that it would look the same if it were cut in half
vertically in any direction.
http://biology.unm.edu/ccouncil/Biology_203/Im
ages/SimpleAnimals/cnidariaDiagram.jpeg
Works Cited: http://cas.bellarmine.edu/tietjen/images/cnidarians.htm
http://animals.about.com/od/cnidarians/ss/cnidarians_2.htm
Feeding
• Cnidarians are mostly carnivorous and
eat small crustaceans and fish.
• They obtain their food by waiting for prey
to drift by and then latch onto it with their
tentacles and paralyzing the food with its
nematocysts.
• After the prey is paralyzed, it is pulled
through the mouth into the gastrovascular
cavity where it is digested by beating
flagella lining the cavity and enzymes
http://baynature.org/articles/jul-sep-2006/from-collecting-torecollecting/v06n03_404.jpg/image_listlarge
Works Cited:
http://animals.about.com/od/cnidarians/ss/cnidar
ians_6.htm
Respiration
• Cnidarians don’t have any lungs or gills.
• They acquire oxygen through diffusion.
• Cells of cnidarians are extremely thin, so the oxygen in the water can easily
pass through all of the cells in the organism.
• Most cnidarians are tiny and/or
thin so that they can distribute the
gases throughout their bodies
• Diffusion between the organism
and the water occurs in the
epidermis and gastrodermis
Works Cited:
http://www.palaeos.com/Invertebr
ates/Cnidaria/Cnidaria.htm
http://photography.nationalgeographic.com/staticfiles/NGS/Shared/Static
Files/Photography/Images/Content/crown-jellyfish-newbert-1145563ga.jpg
Circulation
• As with respiration, circulation occurs through diffusion in cnidarians.
• They don’t have any circulatory organs you see in other animals, such as a
heart or blood vessels.
• They receive their nutrients and gases responsible of circulation through
the water directly by diffusion inside of the gastrovascular cavity
http://oceanexplorer.noaa.gov/explorations/02fire/logs/jul26/media/cnidar
ian_600.jpg
Works Cited:
http://faculty.clintoncc.suny.edu/fa
culty/michael.gregory/files/Bio%20
102/Bio%20102%20lectures/Circu
latory%20System/circulat.htm
Reproduction
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Cnidarians can go through both asexual and
sexual reproduction.
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Asexual reproduction is relatively fast, and the
end result is an exact genetically identical clone.
Asexual Production is often characteristic of
favorable conditions such as in the spring and in
the summer.
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Compared to asexual reproduction, sexual
reproduction is cnidarians is relatively slow. It
usually is characteristic of decline conditions
such as the fall season, and it results in a
genetically dissimilar offspring.
Work cited:
http://www.cbu.edu/~seisen/Cnidaria/sld0
11.htm
Excretion
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Like Respiration, Cnidarians also achieve
excretion through the process of Diffusion.
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Once the nutrients are absorbed, they reach the
outer cell layer through diffusion.
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Parts of a prey that are indigestible, are disposed
of through the mouth.
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Ammonia is the main waste product of the cells,
and is removed by external and internal water
currents.
Work cited: universe-review.ca/R10-33-anatomy.htm
Movements
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Most adult Cnidarians are free floating.
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In the larval Stage, Cnidarians are free
swimming.
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Cnidarians use jet propulsion by sucking
water into the grastrovascular cavity and
then spitting it out in a strong spurt of water
to move themselves.
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Their tissues are very thin, and the lack of
muscles is the reason they use jet
propulsion.
Work cited:
http://en.wikipedia.org/wiki/Cnidaria
Response
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Cnidarians have no brain or central nervous
system.
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They consists of a decentralized nerve nets, which
consist of sensory neurons.
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These neurons cause muscle reaction, each time
a stimuli is presented.
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For example, a certain “smell” might cause muscle
contraction.
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Most of the communication between nerve cells
are via chemical synapses.
Work cited:
cnidariag.blogspot.com/2007_02_01_archive.html
Works Cited
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Klappenbach, Laura. "Radial Symmetry - Radial Symmetry in Cnidarians." Animals Wildlife - Animal Facts, Animal
Pictures, Habitat Facts, Evolution and Zoology. About.com. Web. 15 Apr. 2010.
<http://animals.about.com/od/cnidarians/ss/cnidarians_2.htm>.
Klappenbach, Laura. "Diet - Cnidarian Diet and Eating Habits." Animals Wildlife - Animal Facts, Animal Pictures,
Habitat Facts, Evolution and Zoology. About.com. Web. 16 Apr. 2010.
<http://animals.about.com/od/cnidarians/ss/cnidarians_6.htm>.
"Invertebrates: Cnidaria: Cnidaria." Palaeos. Web. 20 Apr. 2010.
<http://www.palaeos.com/Invertebrates/Cnidaria/Cnidaria.htm>.
"Circulatory System." Clinton Community College. Web. 20 Apr. 2010.
<http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/Bio%20102/Bio%20102%20lectures/Circulatory%20
System/circulat.htm>.
Klappenbach, Laura. "Cnidocytes - Cnidocyte Organelles in Cnidarians." Animals Wildlife - Animal Facts, Animal
Pictures, Habitat Facts, Evolution and Zoology. Web. 16 Apr. 2010.
<http://animals.about.com/od/cnidarians/ss/cnidarians_5.htm>.
"Characteristics of Cnidarians |." The Most Beautiful Butterflies In The World | |. Web. 16 Apr. 2010.
<http://www.butterflyrevolt.com/characteristics-of-cnidarians.html>.
"Cnidarians." W. Fielding Rubel School of Business: Bellarmine University. Web. 16 Apr. 2010.
<http://cas.bellarmine.edu/tietjen/images/cnidarians.htm>.