Spiders travel thousands of miles through the air using their silk to ride electrostatic repulsion instead of the wind. Skeletal muscles contract and relax, generating force and enabling movement.
We use cookies to give you the best browsing experience. By clicking the Accept button you agree to the terms of our privacy policy. Functions Performed More from this Living System. See More of this Function. Capture, Absorb, or Filter Solids Some living systems must secure solid particles such as sediment, usually to keep the particles from hindering their health or activity.
Transform Mechanical Energy Mechanical energy is made up of kinetic energy the energy of an object in motion and potential energy stored energy. Modify Position Many resources that living systems require for survival and reproduction constantly change in quantity, quality, and location. See More of this Living System. The tube feet of echinoderms move and handle food using a hydraulic system. Sea Star Body Plan. Journal article Functional anatomy of the valves in the ambulacral system of sea urchins Echinodermata: Echinoidea Maerkel, K; Roeser, U embedly preview toggle icon Reference toggle icon.
Unlike actual fish, starfish are not good swimmers. Instead they climb around sand, rocks and coral using what are known as tube feet. If you flip a starfish upside down, you will see what looks something like a flower. A deep groove runs along each starfish leg, which slightly resembles a vein going through a flower petal, surrounded by hundreds of raised bumps. You will also see a hole in the middle of the starfish. What you're looking at is called the water vascular system of a starfish.
The hole in the center of a starfish is known as a madreporite. This is where water is taken in from a starfish's surroundings. The water travels through a circular ring canal near the starfish's mouth, which then distributes the water to the radial canals, those deep grooves in the middle of each leg. The rows of little raised bumps surrounding the radial canals are known as tube feet. Then it can be pumped through a series of canals and tubes and used to expand and contract the small structures called tube feet.
By controlling their movement, the animal can move around the sea bed. It's a very different system from the musculoskeletal one found in animals like mammals, birds, etc. Here's a close up of some tube feet:.
And here's a short video of a sea star walking where you can clearly see the tube feet moving:. And one final note, while the term "starfish" is more commonly used, "sea star" is more accurate as these animals are not fish at all!
Lots of organisms have "fish" in their names but aren't fish actually, e. If you are interested in helping with the website we have a Volunteers page to get the process started. Digging Deeper. Digging Deeper: Depression and the Past. Digging Deeper: Germs and Disease. Digging Deeper: Milk and Immunity. How Do We See? How Do We Sense Smell? How Do We Sense Taste?
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