Sea Urchins
Sea Urchins are found almost everywhere on the ocean floor. The exception to this is the colder polar regions where they are not found. There is around 200 total species of some that have thin spikes and other that are covered in chalky plates. They are omnivorous animals, eating both plant and animal matter, feeding mostly on algae on rocks and other decomposing material like fish. Despite being covered in spines, sea urchins still have predators including crabs, large fish, sea otters, eels, and birds. Humans are also one of the main predators of sea urchins, catching them and serving them as delicacies in some countries.
Sea urchin spines are used to move, defend itself, and catch food particles floating in the water. They have five paired rows of small feet in between these spines. The feet have suction cups to help the urchin move, collect food and stay attached to the sea floor. They also have small claw-like parts which are for stinging and keeping the urchin clean.
Like other Echinoderms sea urchins do not have a brain but instead have a system of nerves connecting throughout their whole body. The sea urchin has a ring of nerves around their mouth which then branch out through. The nerves branch out in five main nerves which then follow the water vascular system of the sea urchin.
Sea urchin spines are used to move, defend itself, and catch food particles floating in the water. They have five paired rows of small feet in between these spines. The feet have suction cups to help the urchin move, collect food and stay attached to the sea floor. They also have small claw-like parts which are for stinging and keeping the urchin clean.
Like other Echinoderms sea urchins do not have a brain but instead have a system of nerves connecting throughout their whole body. The sea urchin has a ring of nerves around their mouth which then branch out through. The nerves branch out in five main nerves which then follow the water vascular system of the sea urchin.