Speaking of Science Column March 22, 2009
A 'touching’ story about a surface-lived life
Some things are so obvious that we forget their significance. For example, the fact that life is a surface phenomenon is so obvious that we forget to consider all the ramifications of that fact.
Living things live on surfaces. We simply don’t know life opposite of that fact.
Oh sure, birds fly through the air. But they don’t “live” there. They return to the ground, or at least a tree attached to the ground, to build nests and have babies.
Fish and aquatic mammals swim through the water, but they either return to the shallows to deposit their eggs on the surface, or they have internal fertilization where the female uterus becomes the surface for the babies. It can even be argued that water is a surface phenomenon since it is held to the surface of the earth as a thin film because of gravity and surface tension.
The only times humans experience being “out of touch” with a surface is when they are temporarily jumping or falling. The accompanying feelings can be either disconcerting or mildly pleasant when carefully controlled, such as on a trampoline or a carnival ride.
Scuba divers and astronauts must learn special techniques for maintaining their equilibrium when they experience weightlessness, which is a form of not being “in touch.”
Even pilots must learn special techniques for orientation because they may receive conflicting directional messages among eyes, ears and pressure on their bodies. Most animals, especially wild animals, become alarmed when picked up from the surface.
Domestic animals are usually taught to become accustomed to the experience.
Even very primitive animals are controlled by this necessity to be on a surface or to touch something. Amoeba, some of the most primitive of eukaryotic cells, feed by a process called phagocytosis where they actually engulf their food whole. If this were to occur at random, it would seem to be a process somewhat like bobbing for apples. Therefore, this process occurs most efficiently when the amoeba are on a surface.
For the process to occur at all, the amoeba must literally “touch” its intended food, usually another single-celled organism, and stick to it to hold it in place long enough to engulf the particle. This sticking occurs at the molecular level, and is, therefore, a very close form of touching.
This molecular touching is especially important in the human immune response. We possess phagocytic cells that engulf foreign particles as part of our immune response. I find that if I imagine tiny amoeba scampering around in my body too vividly, it either makes me itch or it tickles. In addition, we have other secretory cells that must touch a foreign particle in order to be activated. For example, we have a cell called a basophil which, when it touches a foreign particle, called an antigen, will release histamine, heparin and serotonin.
These chemicals cause the inflammatory response which is sometimes helpful in fighting off infections.
Most of us are more familiar with the inflammatory response that occurs when foreign particles, such as grass pollen, enter our nasal passageways or eyes, and the inflammatory response is called “hay fever.” But the cause of the response is the same “touching” of basophils by the antigen. If you can stop the touching, you will stop the symptoms. If not, you will need to take antihistamine to counteract the basophil secretions.
Touching is so much a part of our lives that we forget its significance. As you read this article, you are touching the newspaper but you only become aware of that connection when you can’t get the newspaper situated properly. Touching is how we show affection, either positive or negative. Touching is how we orient ourselves and how we manipulate objects. Touching is how we understand our world, something parents and educators too frequently forget. On the surface of things, it is important to stay in touch.
Gary McCallister is professor of biology at Mesa State College and also owner/operator of Flaming Moth Productions and the “Bee bar Bee Ranch,” supplier of native bees, native bee nests and native bee information.