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Animals that exhibit radial symmetry, tissues but no organs and possess stinging cells called nematocysts.

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Did That Jelly Roll?

A Pacific sea nettle (Chrysaora fuscescens)

Why Yes, Yes, It Did.

People's reaction to jellyfish depends a lot on their interaction with them. Step on one walking down the beach, bad reaction. See one in an aquarium, and they're gorgeous, good reaction. Go swimming in the ocean and get stung, bad reaction. Get the opportunity to swim with them underwater in their natural environment, unbelievably good reaction! But apart from humans' actions and reactions to jellyfish, researchers are learning that these creatures play a much bigger role in many more ecosystems than was once believed.

No Duh's and Head Scratchers

If you need help scratching a mental itch, use the resources below:

  1. How is the form of a jellyfish related to the functions a jellyfish needs to carry out to survive? How are these both connected to the environment in which the jellyfish live? How do you think this contributes to people thinking these are simple creatures? How would you try to get people to understand how an open water environment differs from a terrestrial environment?
  2. How did old sampling techniques for the deep sea lead to an undersampling of gelatinous animals? What are researchers realizing now with new sampling techniques? What technology is making this possible?
  3. What kinds of information are researchers now able to collect with new technology? How important do you think this information is for understanding these organisms? What information would you like to collect given the opportunity?
  4. What is the best studied part of the deep sea on the planet? What geographical feature has made this possible? Do you think you could recreate this situation at another location? What sorts of problems would you need to overcome?
  5. Acidity in the world's ocean is increasing due to increasing carbon dioxide (CO2) in Earth's atmosphere. Several lines of research suggest this increased acidity will benefit jellyfish, and they will come to dominate the world's ocean. If this does happen, how would it affect your view of the way evolution works? Keeping in mind your current view of evolution, do you think it makes sense that a "primitive" organism could become "Ruler of the Seas"?


Millions of endemic jellyfish (Mastigias papua etpisonii) fill a marine lake in the Republic of Palau. Palau has five different marine lakes filled with different subspecies of jellyfish.

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