Most people recognize Darwin as the man who brought about the theory of evolution. There were many others who had similar theories, but his work is still considered important by many scientists today.

That being said, there were many things that Darwin could not figure out and there are plenty of holes in the evolutionary theory that need to be addressed.

Photo: YouTube/PBS Eons

Regardless of whether you believe in evolution or not, there is one important factor that is interesting to consider.

One of the issues that Darwin had was trying to figure out the classification of the simple barnacle. According to the Woods Hole Oceanographic Institute, Barnacles exist almost everywhere in the ocean, and they certainly are no secret when it comes to what they are and what they do.

Photo: YouTube/PBS Eons

The problem was it was difficult to classify the barnacle because they seem to exist somewhere between a mollusk and a crustacean.

A video by PBS Eons notes that Darwin, himself, was frustrated over the situation at one point, and he even said, "I hate a Barnacle as no man ever did before."

Photo: YouTube/PBS Eons

Darwin reportedly wanted to figure out more about the situation, so he went on an eight-year personal quest to determine where they belonged. In the end, he agreed with another scientist, William Thompson, and said that they were a crustacean.

Of course, the simple fact that a barnacle is a crustacean does not mean that it evolved from a lower species. It simply means that they fit into that category, and that is interesting to know.

You can learn more about it in the video below: