Is the sea urchin a plant or an animal? There are many creatures living in the sea, including many plants and many animals. Among them, sea urchin is one of the many marine organisms. From the appearance characteristics, sea urchins are not like animals, and they generally do not move. Therefore, many people will mistake sea urchins for plants. In fact, sea urchins are animals, and echinoderms, not plants. There are many species of sea urchins. There are more than 900 species of sea urchins in the world. They are all animals. They all belong to echinoderms.
As a kind of echinoderm, sea urchin is also an invertebrate, so they are relatively low, the body structure is relatively simple, there are many advanced tissues and organs in the sea urchin body does not exist. They are omnivores in the ocean, eating not only algae and other plants, but also worms and other small animals. But they can only eat food that is small in size, because they are small in size.
Sea urchins are animals, and echinoderms, or invertebrates, not higher animals. Mammals, on the other hand, are vertebrates and are among the higher classes of vertebrates. Therefore, sea urchins can not belong to mammals. Compared with mammals, sea urchins are quite different. An important feature of mammals is the use of viviparous reproductive methods, and there will be a certain period of lactation, sea urchins reproductive methods are very different. In addition, the lungs are relatively unique respiratory organs in mammals, but the body structure of sea urchins is too simple, and there is no such advanced respiratory organs.
