Brains are awesome. Zombies eat them. Cannibals eat them. Hot-spring dwelling amoebas eat them. Aliens in sci-fi eat them. Also, brains are good for information storage and stuff. It is important to have brains. But would extraterrestrials have brains (that they haven’t sucked out of humans)? In Agent to the Stars, a book by John Scalzi, the extraterrestrials are basically big blobs of goo. They have no brains. They presumably store information, perform bodily functions such as metabolism and waste removal, and engage in movement in all cells. That would be awesome for us. There would be no kidney failure, no brain tumors, no broken bones, no disease! Why then aren’t we big blobs of goo? Wouldn’t big blobs of goo be simpler to evolve than all of our specialized cells? I mean we have a different organ for every bodily function, and each of those organs is made up of a complex structure of cells. Wouldn’t it be simpler to just have one cell that does everything?
The truth is there are cells that do everything. They are called bacteria (and also amoebas, protists, archaeans,etc.). In an evolutionary sense, bacteria and other single-celled organisms are quite succesful. They are in every environment on earth, including boiling battery acid, glaciers, highly saline environments, and even in our guts. They can form colonies, cooperate with other organisms and reproduce in fantastic ways. However, these cells, that do everything, do nothing well. This is not to say that single-celled organisms are slackers. It just means they are not adapted for passing on signals, protecting other cells, or storing information. They are adapted to reproduce, and exchange nutrients and waste with their environment. That is the problem. They require so much energy to perform these basic functions that they have none to spare for extraneous information storage. Intelligence (loosely defined as non-DNA information storage,and exchanging signals to facilitate movement and reaction to an environment) requires specialized cells that are not involved in consumption of nutrients or reproduction. Our glial cells provide protection, nutrients and insulation to neurons. Neurons have very little to do but pass signals on and store information but they do it well. Therefore, I predict that any intelligent extra-terrestrial species will have specialized brain cells.
Note: I absolutely love Agent to the Stars and John Scalzi’s books in general! I recognize that he must be more creative, more intelligent and a better writer than I and I do not wish to denigrate his many accomplishments. This post is intended to set forth an argument and a prediction about differentiated tissues. If you disagree with my argument, please feel free to comment (politely!) about my wrongheaded-ness.