THE AMOEBOID BRAIN

If you lived on the surface of a rock in a pond and were only about 5 micrometers thick (a micron is 1/1000th of a millimeter), your life would be very different. You couldn't really fall down, since down is an extremely tiny distance. Up wouldn't make much sense either because it is relative to down. There would, of course, be forward and back, if you had some way to tell which was which. If you were quite round it might be more difficult. If you had an elongated shape I suppose you could have a right and left, but if you are more or less amorphous, those two concepts would be just a hazy notion of sideways to some degree or another.

Thus is the life of most amoeba, I suppose. If you find this thought intriguing you might enjoy reading the classic short book by Edwin A. Abbott called "Flatland: a romance of many dimensions". He explores life of a Mr. A. Square in a land of two dimensions. But A. Square's life must be very much like an amoeba's.

Yet amoeba can do some amazing things. If you place amoeba in a container and place a food supply in any direction from them, they will all eventually turn and begin to move in that direction. If you place toxic chemicals in their environment, they will move away from the source of irritation. If they like the dark, they can find the deepest shadows.

This is even more amazing. Amoebas grow by simple fusion, dividing in two. If you take a population of any given species of amoeba from some pond and allow them to develop large numbers, and then mix them with another population of the same species but from a different pond, they will live happily together. However, if you then cut off their food supply; they will eventually eat members of the other population, but will starve to death before eating members of their own type. They can recognize their own progeny. I sometimes look at my grand kids and can't even do that.

The amoeboid world is pretty slow as well. All amoebas live in aquatic environments. Life in the fast lane for an amoeba might be a fish swimming by and creating a current. They don't float free in the water normally, but are restricted to their two dimensional world, to which they cling tenaciously with their ever changing arms called pseudopodia. But they know all of this, and if they should be suspended in water by the fishy currents, they cease trying to move until they are safely settled back onto a nice two-dimensional plane.

Living in water, you might expect that they aren't very fast also. One of the faster amoebas around can sprint at speeds of 0.5 to 3.0 micrometers per second. I think that makes their fastest time for a "one millimeter dash" around 5 minutes. However, many amoebas are slower than that. Still they seem to get where they want to go.

You might wonder why it is important to know anything about amoeba. There are actually a lot of reasons, some involving disease, other involving their role in nature and the food chain.

But the reason that I find most interesting is that they seem to be able to do a lot of the things I can do, but with only a single cell. True, they can't do algebra, but then I'm not very good at that either. They don't talk, or at least in an audible language. They do communicate very complicated information chemically. In fact, amoeba can talk to one another. By secreting chemicals, they can tell other amoeba what they are doing and what they want the other amoeba to do. This is exactly what the cells of your brain do: secrete chemicals that communicate with other brain cells. That is exactly what the brain is composed of cells speaking a chemical language to one another.

So do amoebas think? I guess that all depends on what thinking is, and thinking may just not be what you think it is. And amoeba may prove to be more interesting than you think.