I love jellyfish. It probably has something to do with living inland and only having seen the ocean two or three times in my life, but it's also because there is something just plain fascinating about them. They just look so darned improbable and they have a fascinating life cycle.
The jellyfish that we commonly see in pictures are at the medusa stage. They are round and filled with water and have long trailing tentacles that can sting prey. These come in male and female and make eggs and sperm respectively. When the eggs are fertilized they become a cilliated larvae that settles to the ocean floor and forms a polyp.
Polyps look kind of like strange, alien flowers with finger-like petals. They are usually very small, less than an inch tall and those "petals" gather food for the polyps. Each polyp can break off little peices of itself that are called buds and the buds make tiny little medusa that grow up to look like the original parents. In this way, each fertilized egg can result in a great many genetically identical adults that can then wash up on beaches and sting people.
Links
Here is an article on National Geographic Kids. It includes what to do if you get stung.
Here is a scientific article that shows how jellyfish blooms and algae blooms can interact.
These guys won the Nobel Prize by making glowing jellyfish protiens usefull to other scientists.
Word Of The Day
Nematocysts: The stinging cells of the jellyfish.
Nematocysts: The stinging cells of the jellyfish.
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