Download Cnidaria Kat Hunter Piper

CNIDARIANS
By: Kat Johnston, Hunter Dost and Piper Wetzel
Cnidarian
Any invertebrate animal, as a hydra,
jellyfish, sea anemone, or coral,
considered as belonging to the phylum
Cnidaria, characterized by the
specialized stinging structures in the
tentacles surrounding the mouth.
Vocabulary:
Gastrodermis: Is the inner layer of cells that serves as a lining membrane of
the gastrovascular cavity of Cnidarians.
Mesoglea:
Is the translucent, non-living, jelly-like substance found between
the two epithelial cell layers in the bodies of cnidarians.
Nematocysts: a specialized cell in the tentacles of a jellyfish or other
cnidarians, containing a barbed or venomous coiled thread that can be projected
in self-defense or to capture prey. Also known as cnidae.
Medusa: A free-swimming sexual form of a cnidarian, typically having an
umbrella-shaped body with stinging tentacles around the edge.
Polyp: A solitary or colonial sedentary form of a cnidarian, typically having a
columnar body with the mouth uppermost surrounded by a ring of tentacles
CHARACTERISTICS
● Gastrovascular cavity: Cnidarians possess only one digestive opening,
which serves as both the mouth and the anus. This opening is
surrounded by tentacles and leads to an internal digestive cavity.
● Body plans: Radially symmetric
● They have three tissue layers, an outer protective epidermis, a middle
layer called the mesoglea, and an inner layer called the gastrodermis,
whose function is primarily digestive.
●
Most cnidarians possess tentacles, and many also have nematocysts
(specialized stinging cells). Both are involved in feeding.
Phylum life characteristics
Digestion- The Cnidarians digestion system is very complex, but also very simple. They all have a one way
digestive system. Which means all the food goes through the same way. This process is called
Gastrovascular cavity.
Excretion- Cnidarians have a canalike cavity within their two layered bodies. For ingestion, digestion and
egestion for food and waste.
Reproduction- All cnidarians reproduce sexually. This occurs in one phase life cycle which is usually
medusa. They can also reproduce asexually, but that occurs with both phases. The other phase is called
Polyp.
Circulatory System- Cnidarians do not have a circulatory system because they don’t need one. All their
cells are connected with water, which contains oxygen and nutrients. The cells undertake a process of
diffusion to transport oxygen, waste and nutrients into the organism.
Respiration- Cnidarians breathe through gas exchange. They do not have gills or lungs like most maries
do.
Classification
Hydrozoa:
1.
Mostly Marine
2.
Only class with freshwater members
3.
Alternate generations
4.
Mostly colonial polyps
5.
Only have cnidocytes in epidermis
Classification
Scyphozoa:
1.
True “jelly-fish” - Polyp form reduced or
absent
2.
All marine
3.
Cnidocytes in gastrodermis and endodermis
4.
gametes form in gastrodermis
Classification
Anthozoa:
1.
No medusae, polyp only
2.
Mouth has a pharynx
3.
Sexual and asexual reproduction
Classification
Cubozoa:
1.
Medusa is cuboidal
2.
Tentacles hang from corners
3.
Polyps reduced or absent
Fun Facts:
1.
Cnidarians are known to be older than dinosaurs.
2.
The name Cnidaria comes from the Greek "Cnidos" meaning stinging
nettle.
3.
A group of jellyfish is called a bloom or swarm.
4.
The firing of nematocysts are the fastest reactions in the animal
kingdom.
5.
Box jellyfish venom is the most deadly in the animal kingdom and
has caused at least 5,568 recorded deaths since 1954.
Fun-Facts:
1.
Cnidarians don't have brains or hearts
2.
some jellyfish are as big as a human and others are smaller
than a match
3.
some of the chemicals produced by corals help scientists
learn about anti-cancer drugs
4.
Some Cnidarians are the longest animals in the world, one
of them that can stretch as long as 40m
5.
Cnidarians can weigh up to several tons
Cited Information
http://dictionary.reference.com/ - Dictionary for vocab
https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=google%
20images - Used for all pictures
https://sites.google.com/site/cnidarians4life/special-or/interesting - Fun-facts
http://digestivemack.weebly.com/cnidaria.html - Digestive info
http://www.encyclopedia.com/topic/Cnidaria.aspx -Cnidaria facts
http://cnidarianh.blogspot.com/2007/02/feeding-respiration-excretion.html - Excretion
http://www.britannica.com/animal/cnidarian - Reproduction