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A Jelly's Life
Jelly Home
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| Adult
medusas |
© Joyce Bergen |
The
adult stage of the jellies' life cycle is called the medusa.
This is the stage that many of us think of when we think
jellyfish. Adult jellies are either male of female. Males
project their sperm out into the water. Female jellies either do
the same with their eggs or, like the moon jelly, hold them
under their bell. |
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| Gametes |
© Joyce Bergen |
Eggs
are fertilized by chance, either out in the water or under the
protection of the female jelly's bell. After the moon jelly's
eggs hatch the larvae hang out under the mother's bell for a
time. They look like purple popcorn (look for them on the
Aquarium's JellyCam). |
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| Larvae |
© Joyce Bergen |
Out
of the eggs hatch the jelly larvae, beginning
yet another stage of their planktonic lives. From here the
larvae float around the ocean searching for a solid surface to
attach to. This can be more difficult that it sounds, especially
if the jelly lives out in the open ocean, thousands of miles
from the land and miles from the bottom. In this environment,
floating seaweed and debris may be their only refuge. |
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| Polyps |
© Joyce Bergen |
Once
attached, the larvae grow into polyps. Think of
polyps as upside-down jellyfish. Their bodies have attached to
the surface and their tentacles now stick up, collecting food
that might happen by. In this stage of their life, jellies can
do a different kind of reproducing. Polyps can clone themselves
through a process called budding, where little polyps grow from
the main polyp stalk. |
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| Strobilation |
© Joyce Bergen |
From
just one polyp, many adult medusas may arise. Through strobilation,
the polyp divides itself into dozens of flat segments. These
segments peel off from the stack and float away as young adult
jellies called ephyrae. |
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| Ephyrae |
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© Joyce Bergen
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From
here it's all eating and growing. Ephyrae,
themselves still in the plankton, feed on smaller plankton and
develop until they become adult medusas,
and the cycle can begin again. |
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