Sea urchins do not have the structure of eyes, they only have some eyespots and photoreceptor cells. Eyespots are located on the epidermis of their anti-oral surface, and photoreceptor cells are not only found on the epidermis of the anti-oral surface, but also on spines and tube feet. Their eyespots and photoreceptor cells help them sense light, allowing them to respond to changes in the external environment. They are sensitive to ambient light, but cannot see specific things clearly. 1. Do sea urchins have eyes?

Sea urchins are a kind of marine animal that we are familiar with, and some sea urchins are still edible. When many people observe sea urchins, they will find that although they are also animals, their body structures are different from many animals we are familiar with. In fact, sea urchins are invertebrates. Compared with vertebrates, they do not have many structures. This is because they have not evolved similar structures in the process of evolution.

For example, sea urchins do not have eyes. Although they don't have eyes, they do have similar organs to sense their surroundings. This is the result of years of evolution as sea urchins adapt to the marine environment. For example, there are some epidermal cells on their anti-oral surfaces with eyespots that can be used to sense external light. In addition, there are enough photoreceptor cells on their spines and tube feet. In fact, sea urchins are generally quite sensitive to surrounding light. Of course, their eyesight cannot be compared with humans and most other animals, but it can already meet the needs of sea urchins' life activities. 2. Do sea urchins have mouths?

As mentioned above, sea urchins do not have eyes due to their relatively simple body structure. However, sea urchins have mouths so they can eat. Many people will have seen sea urchins eating, and their mouths are relatively obvious at this time. When sea urchins are not eating, their mouths are not easy to observe, but if you look carefully, you can find that there is a relatively small white part on the surface where there are no spines, which is the mouth of the sea urchin.