By: Chelsey McIntosh
What are Jellyfish?Also known as jellies or sea jellies, jellyfish are free swimming marine invertebrates that are members of the phylum Cnidarian. They are jelly-like and almost transparent with a bell shaped body. Jellyfish generally have long stinging threads on the surface. They are among the largest planktonic animals, they feed mostly on zooplankton and small fish. Some jellyfish can grow as large as 2 meters in diameter, with tentacles much longer.
Characteristics of the Phylum Cnidarian
They have radial symmetry blind sac gut (coelenteron or gastrovascular cavity)diploblastic with mesoglea polyp and medusa body formsnematocysts (specialized stinging capsules)nerve net lack excretory, circulatory & respiratory systems complex life cyclemany colonial forms exhibiting polymorphism
The largest type of jellyfish can be up to 120 feet long. (Lion’s Mane Jellyfish)In Countries like Japan, China and Korea it is a considered a delicacy to eat Jellyfish.
Did You Know?
Most jellyfish have at least two distinctly different body forms in their life cycles.Polyp-This is when they take the form of a stalk with feeding tentacles.Medusa-tiny jellyfish which then grow into a large jellyfish.
Who preys on Jellyfish?
Jellyfish are preyed upon by; tuna, shark, pacific
salmon and sea turtles. Some
jellyfish are even preyed upon by larger jellyfish.
How do Jellyfish protect themselves?
Jellyfish use their tentacles to protect themselves, barb
like filaments found on the tentacles pierce their victim,
once this occurs venom is released from the filaments
into the victim.
How do Jellyfish move?
Jellyfish move like an umbrella, their jelly
like “skin” opens allowing water to
enter, it then closes using the pressure created from the
release of water to move.
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