Freaky Eaters Of The Deep : Echinoderms characteristics and examples

They will be eating with their feet, their spines, and even their anus. Is this a dream? Where are you?

You’re seated at a table for lunch. Your hands are neatly folded in front of you. All around, your lunch-mates devour scraps off the floor. They will be eating with their feet, their spines, and even their anus. Is this a dream? Where are you?

You’re with the echinoderms (EE – KY – NO – DERMS): sea stars, feather stars, sea urchins, sea cucumbers, sea lilies, and sand dollars. And this lunch is taking place at the bottom of the ocean.   

While you’re enjoying a soup in a recyclable container with a biodegradable straw, these animals snack on kelp, krill, algae, plankton, and each other. Listed here are some examples of common echinoderms and their characteristics.

Feather Star, Image Credit : Lakshmi Sawitri

The most human-like eater of the bunch is the feather star, which drifts throughout the meal and directs particles towards its mouth with its arms. It might amuse you as you sit, sipping on your soup, to see them float past your face. Meanwhile the sea lilies, like most of the other echinoderms, sucks up bits up with its feet from the ocean floor to deposit into its food groove.

Sand Dollar

The sand dollar moves food along its spine towards its mouth. The sea urchin, with five bony plates forming a beak, scrapes its food off the sea floor and directs it with its tube feet. Tube feet are a special development of the echinoderms – no other creature has them. Try pulling an echinoderm off a rock as you sip and you will be surprised at the strength of these tiny animals.

Sea Cucumber, Image Credit : Nevit Dilmen

But it’s the sea cucumber that might set your head spinning. It eats with its anus. Because it has no blood, the sea cucumber uses its anus to suck in water and distribute nutrients throughout its body. Riding in along with the water are bits of food, which is absorbed into its inner organs.

Star Fish

The sea star (which used to be called a star fish), climbs up the legs of the table. You may be sorry it does: sea stars are carnivorous and snack on urchins and even other sea stars. The way it does it might be a little hard to watch. The sea star’s stomach comes right out of its body, surrounds its prey, and digests it. Its stomach fluids dissolve the prey’s body until it’s like a soup – a bit like the one you are sipping. Its stomach then recedes back into the creature. You probably don’t know anyone else who eats like that.

Such a lunch at the bottom of the ocean would be very interesting, and maybe a touch worrying. But these brainless animals can teach us a lot about the different ways life forms in nature and survives for millions of years. Your lunch may seem a little less appetizing, but you’ll be sure to remember your meal with the freaky eaters of the deep.

GLOSSARY
– Echinoderm – the largest family of salt water animals
– Recyclable – process again for reuse
– Biodegradable – capable of breaking down by natural means
– Kelp – seaweed
– Krill – small, shrimp-like marine animal
– Algae – types water plants
– Plankton – tiny animal and vegetable organisms floating in water
– Marine biologist – a person who studies life in the sea
– Polyp – the living animals that form coral
– Ecology – the science of natural life

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