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Cells specialized even more than sponges and tissues (groups of similar cells) began with the jellyfish family. Nerves and muscles first appear in these animals, although they had no brain. Their behavior is very simple, responding automatically to touch. Nerves can carry more information between cells than hormones can. Nerves are the main feature which makes animals different from plants. Jellyfish might have evolved into flatworms.
Jellyfish might have appeared 650 million years ago. They belong to the group of animals called Cnidaria or Coelenterata. This group includes corals, hydras, jellyfish, Portuguese men-of-war, sea anemones, sea pens, sea whips, and sea fans. They are closely related to the comb jelly group, or Ctenophora |
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Biological Environment > Jellyfish
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This site tells the story of the history of the universe. Click Earlier and Later to follow the story.
Note: Many facts have been simplified to make them easier to understand.
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Note: Many facts have been simplified to make them easier to understand.
Click here to read Time Crystal, history of the Universe as sci-fi fantasy romance!
