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Jellyfish
As a species jellies have been around for a very long time. They appeared in the oceans about 650 million years ago, before the dinosaurs. They still populate our oceans today in a profusion of sizes and shapes. Jellyfish are incredible creatures - it's amazing that they are living things. Check it out...their bodies are made up of 95% water, they have no bones or cartilage, no heart or blood, and no brain! (Talk about a real no-brainer). They are one of earth's simpler and more primitive life forms. The picture you see at left is a much smaller specimen of a lion's mane jelly. The world-record holder was found dead, washed up on a beach.
Scientists have determined that some jellies have eyes that can detect light from dark and even some movement of objects in their field of vision. It doesn't seem possible that any living creature could have eyes, but NO BRAIN. The brain is where the processing of visual stimuli happens in most higher-order species. How does the procedure work in jellies with eyes and no brains? Scientists don't really know for sure, but by studying jellies they can learn a lot about how vision works and what role the brain plays in processing visual input.
Jellyfish
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