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Welcome to MooMooMath and Science. In this video I'd like to talk about the phylum

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cnidarians. Cnidarians are invertebrates that are famous for stinging

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cells and they have radial symmetry. Let's take a look at probably the most

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famous cnidarian, the jellyfish. Cnidarians are famous for their sting.

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However, some do have a sting in which they inject venom and others entangle their prey

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with sticky hairs or tentacles.

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Here's what a harpoon would look like from a cnidarian with a stinging cell.

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There are two main types of cnidarians.

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The medusa have their tentacles hanging down.

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Let's take a look at a medusa in which the tentacles are facing upward.

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The sea anemone is the most famous here.

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Nadarians move by jet propulsion inside their bell and what happens is that it allows them

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to propel themselves forward, not real fast, but it works.

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Sea anemones move also.

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They move very slowly over the rocks or they may move with a wiggle with their base.

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Take a look at this example.

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Cnidarians do not have a central nervous system but they do have a very crude nervous system

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or a nervous net.

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Cnidarians can reproduce both sexually and asexually and with asexual reproduction they

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bud or they divide into a new organism.

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Here's an example of one life cycle.

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There are your cnidarians, the stinging

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or sticky animals. They sometimes

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run your visit to the beach. Thanks for watching.

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