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What is the role of sea urchins?
Sea urchins are important herbivores on coral reefs, and in some ecosystems they play a critical role in maintaining the balance between coral and algae. Their role can be especially important on reefs where other herbivores (such as parrotfishes and rabbitfishes) have been depleted.
How do sea urchins protect themselves?
To protect themselves from predators, sea urchins will react immediately if something sharp touches their shell and they will point all of their spines towards the area being poked. They are also light-sensitive. This light sensitivity also allows sea urchins to move their spines in reaction to shadows.
How does the sea urchin help the crab?
Carrier crabs have a mutualistic relationship with several species of sea urchins, which means that the interaction benefits both animals. The crabs gain protection from predators. If a predator approaches, the crab will tip its back towards the predator which aims the urchin at the fish.
What is the relationship between a purple sea urchin and a lined chiton?
The purple sea urchin and the lined chiton share a commensal relationship. Biologically, this means one organism receives a benefit — such as food, shelter or protection — without either harming or benefiting the host organism.
What does a sea urchin need to survive?
Sea urchins have several adaptations to help them survive. To protect themselves from predators, sea urchins will react immediately if something sharp touches their shell and they will point all of their spines towards the area being poked. They are also light-sensitive. This is why they are nocturnal.
What is the function of the water system in a sea urchin?
Used for locomotion and to move loose food particles toward the mouth. Used for defense and movement. If broken they can regenerate. The water system of a sea urchin helps control its tube feet, which allow it to move and to grasp food particles. It works like a hydraulic system. Sea urchins aren’t the only animals with a water system like this.
How do sea urchins mate and reproduce?
The sea urchin’s tube feet are powered by water flowing in and out of them, and equipped with suction cup-like feet. Sea urchins reproduce via external fertilization. This means that, when male and female sea urchins breed, the sea urchins release their gamete (reproductive) cells into the ocean.
Are sea urchins easy to take care of?
Some species of sea urchins make a wonderful addition to salt water tanks, as they feed on algae. Salt water aquariums are, however, expensive and difficult to maintain. The level of care depends on the species, but in a tank with stable temperature, salt, and pH, sea urchins should be relatively easy to maintain.
Why do sea urchins have holes in their shells?
That is because the sea urchins actually make those holes themselves! They use the five teeth in their mouths to carve holes into the rock around them for better protection from predators. Pedicellaria – In addition to their formidable spines, sea urchins have tiny claws on the surface of their shells in between their spines.