March 20, 1998
Modern ecology is based on the principle that everything
eats everything else.
Most branches of biology deal with small divisions of life. Genetics deals with heredity, cell biology deals with cells, mammalogy deals with mammals etc. Ecology, the study of the interaction of living things with each other and the environment, deals with everything at once. Back when I was a student, most bright young scientists avoided ecology because it dealt with too many things at the same time. It was very difficult to get a handle on anything. Since then, not only has ecology become respectable, it has become popular. Nowadays, people who don't know a gene from a golf ball toss the word around as if they understood it. Statements like "It's going to wreck the ecology," document the level of ignorance of the public on the subject.
The proper study of ecology has to include almost everything that has an effect on an ecosystem. If what is being studied is a small uninhabited island, it is relatively simple, compared to one that is inhabited by man. I say "relatively" because the ecology of an island that is not inhabited by man is still extremely complex. An ecological problem that deals with a single species is much simpler than one that deals with the total ecology of a piece of land or water.
The most difficult thing about ecology is that the damn subjects won't stand still; things are always changing. Just counting the numbers of plants and animals really doesn't tell you what is happening. The French physiologist Claude Bernard(1813-78) described the physiologists of his day as "standing outside a house and watching what goes in the door and what comes out the chimney, and deducing what is going on inside." That still applies to just about any field of study that is as broad as ecology.
A mainstay of modern ecology is based, as the title of this column implies, on the principle that everything eats everything else. Plants take raw chemicals from the air, water and soil and build the plant; animals eat the plants; other animals eat those animal etc. etc. Eventually the animal which is so big and powerful that no other animal eats it, dies. It is then eaten by bacteria and fungi. The bacteria and fungi die and put their chemicals back into the soil where they are used by plants and the cycle starts all over again. But it really isn't that neat; because everything is happening at the same time.
It is possible to do experiments with ecology, by removing a species or introducing a new species. Many of these studies happened as a consequence of people introducing new species to an area, such as the rabbit to Australia. The rabbit was introduced as a food source and it soon became a pest. Then things were introduced to control the rabbits and they turned out to be worse. A virus that is deadly to rabbits was introduced to Australia. The virus got back to England and decimated the rabbit farms there. There are other examples, such as the rats that were accidentally introduced to Hawaii by ships. The mongoose was introduced to control the rats and they destroyed much of the native wildlife.
Much of what conservationists or preservationists mean when they talk about ecology is keeping things as they are or were. That involves a value judgment about how things should be. And how things should be is often thought to be the way that they were before man, particularly Europeans, came on the scene. It also involves judgments that plants like the star thistle are bad, bad, bad; while plants like wild oats are good. To the biologist, moral judgments such as good or bad shouldn't enter into it. His business is to study what happens and why it happens. He is a scientist, not a clergyman. But the people who deals with changing or preserving things aren't scientists. They are people who make things happen; for good or ill. What is good or ill? Well, what's bad for the cat may be very good for the mouse.
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