Starfish is a kind of creature living in the ocean, the body is pentagonal star, with ornamental, some species can be eaten. In terms of classification, starfish belong to echinoderms and invertebrates. In the process of evolution, echinoderms are a relatively high class of invertebrates, and starfish are a typical class of echinoderms. Nevertheless, compared with vertebrates, they are still much lower, and many structures are not available. For example, they have no real eyes, only eye spots that can be used to sense light.
In addition, starfish have some structures that are not directly available, such as the brain. Most vertebrates, especially the more advanced creatures such as birds and mammals, will have brains, and have relatively developed brains, which can be used to think. But lower organisms such as starfish do not have this structure. But a starfish has a nerve center. Depending on their nerve centers, they can sense their surroundings. In the process of hunting and evading the pursuit of prey, starfish use their nerve centers.
As mentioned above, the starfish, as a kind of echinoderm, is a relatively advanced class among invertebrates, but compared with vertebrates, they are relatively low, and their body structure is relatively simple. The heart is a biological evolution to a certain extent to produce the organ, only in more advanced animals have, as the echinoderm of the starfish is not the heart of this structure.
