Sea Urchin Body: One Big Eye

Recently, I read an article titled, "Body of Sea Urchin is One Big Eye" written by Charles Q. Choi, Special to LiveScience. In this reading, I found the information very intriguing and learned more about sea urchins than I ever knew before.

To begin, I took this article as a fascinating way to learn how sea urchins see. Now, because they don't have eyes, this might be pertained as very difficult. However, according to the article, "Genetic analysis of sea urchins has revealed they have light-sensitive molecules, mostly in their tube feet and in tiny stalked appendages found in among their spines." Thus, this explains the reasoning for considering a sea urchin body to be "One Big Eye". Plus, with their spines, the creatures can pick out fine details by screening out light from off angles, according to scientists.

On the other hand, this theory had to be proven. Johnsen, a marine biologist at Duke University, and his colleagues, experimented with California purple sea urchins (Strongylocentrotus purpuratus). In this experiment, the group would put 39 of the urchin specimens into a brightly lit four-foot wide arena and see how they responded to the black disk on the wall. When the disk was three-and-a-half inches wide, the sea creatures reacted strongly. In result of this foreign object, two-thirds of the group swam towards it while the other portion swam away. The opposite responses towards this disk may have had to do with whether the sea urchins saw the disk as a shelter or predator. Furthermore, according to Johnsen, "To say the 'raced' toward the discs is relative - watching these guys move is like watching paint dry." Therefore, it is evident that the sight of these animals may not be what we humans have, judging by the speed of their movement.

In addition, even though sea urchins don't have brains, "it could be their entire nervous system more or less acts as a brain," according to Johnsen. Instead of being like us humans and having one main control center, they more or less don't have one, as far as scientists have researched. Additionally, their nerves are extremely small, making it even harder to research than normal. Also, it seems as though sea urchins carry out eyesight and brain work like scientists design robots these days.

Though research continues to be done on this amazing species, researchers still have many questions. Some of which are, "Are these urchins that always run away or run towards them?" and "Do we have timid or bold urchins? Or is it just something specific to how an urchin feels at a certain time?" All of these questions have come from Johnsen after his experiment with the California purple sea urchin. However, these questions could be answered easily, simply by clipping the spines off of this sea creature to find out how they contribute to vision. Although, despite the fact that this procedure may "make sense", it could make the sea urchin very sick, and possibly die. Along with this, if researchers were going to go through so much trouble finding out how their spines would help them see, would they go to the most extreme levels which could possibly harm them and not even get the best results?

Personally, I feel the topic of sea urchins is very bold and engaging. Before reading this article, I had no idea that sea urchins did not have actual eyes. Using their nerves to locate predators and shelter is a very interesting way of living. The experiment with the black disk was really cool because it is always fun to read about an animals reaction to certain situations. I've constantly been attracted to animal behavior and sciences, so naturally, I find this article to be far from a bore. On top of that, I would much rather see these scientists do more experiments like the one with the black disk than cutting out their spines. My reasoning for this is that, personally, I feel there is no point to hurting this creature, just to find out how their spines connect to their ability to see. Not only could this demonstration hurt the sea urchins, but it could potentially kill them. In my opinion, there are much better ways to go about sea urchin research than to put them in danger while doing it. All in all, this is the information I recently learned from the article, "Body of Sea Urchin is One Big Eye" by Charles Q. Choi, Special to LiveScience, and my opinion of it.

Article and Picture: http://www.livescience.com/animals/091228-sea-urchin-eye.html