This is due to the fact that the varieties of chemical substances actually found in living things are vastly more restricted than the possible varieties. A striking illustration is that if one molecule each of all the possible types of proteins were made, they would together weigh more than the observable universe. Obviously there are a fantastically large number of protein types that are not made by living cells. And on the basis of the foregoing, one would reason that many of these possible protein types were once formed in some particular living things, found to be harmful, and rejected through the death of the experiment. In the same way, living cells synthesize fatty acids (a type of organic molecule that contains carbon chains of various lengths) with even- numbered carbon chain lengths (i.e., 4, 6, 8, etc., carbons), but no fatty acids with odd-numbered carbon chain lengths. This suggests that the latter have once been tried out and found wanting. Similarly, organic compounds that contain attached nitrogen and oxygen atoms are singularly rare in living things. This should warn us that the artificial introduction of substances of this type would be dangerous. This is indeed the case, for such substances are usually toxic and frequently carcinogenic. And, I would suppose from the fact that DDT is nowhere found in nature, that somewhere, at some time in the past, some unfortunate cell synthesized this molecule—and died.
One of the striking facts about the chemistry of living systems is that for every organic substance produced by a living organism, there exists, somewhere in nature, an enzyme capable of breaking that substance down. In effect, no organic substance is synthesized unless there is provision for its degradation; recycling is thus enforced. Thus, when a new man-made organic substance is synthesized with a molecular structure that departs significantly from the types which occur in nature, it is probable that no degradative enzyme exists, and the material tends to accumulate.
Given these considerations, it would be prudent, I believe, to regard every man- 35 made organic chemical not found in nature which has a strong action on any one organism as potentially dangerous to other forms of life. Operationally, this view means that all man-made organic compounds that are at all active biologically ought to be treated as we do drugs, or rather as we should treat them—prudently, cautiously. Such caution or prudence is, of course, impossible when billions of pounds of the substance are produced and broadly disseminated into the ecosystem where it can reach and affect numerous organisms not under our observation. Yet this is precisely what we have done with detergents, insecticides, and herbicides. The often catastrophic results lend considerable force to the view that "Nature knows best."
The Fourth Law of Ecology: There Is No Such Thing as a Free Lunch
In my experience, this idea has proven so illuminating for environmental problems that I have borrowed it from its original source, economics. The "law" derives from a story that economists like to tell about an oil-rich potentate who decided that his new wealth needed the guidance of economic science. Accordingly he ordered his advisers, on pain of death, to produce a set of volumes containing all the wisdom of economics. When the tomes arrived, the potentate was impatient and again issued an order—to reduce all the knowledge of economics to a single volume. The story goes on in this vein, as such stories will, until the advisers are required, if they are to survive, to reduce the totality of economic science to a single sentence. This is the origin of the "free lunch" law.
In ecology, as in economics, the law is intended to warn that every gain is won at some cost. In a way, this ecological law embodies the previous three laws. Because the global ecosystem is a connected whole, in which nothing can be gained or lost and which is not subject to over-all improvement, anything extracted from it by human effort must be replaced. Payment of this price cannot be avoided; it can only be delayed. The present environmental crisis is a warning that we have delayed nearly too long.
The preceding pages provide a view of the web of life on the earth. An effort has been made to develop this view from available facts, through logical relations, into a set of comprehensive generalizations. In other words, the effort has been scientific.
Nevertheless, it is difficult to ignore the embarrassing fact that the final generalizations which emerge from all this—the four laws of ecology—are ideas that have been widely held by many people without any scientific analysis or professional authorization. The complex web in which all life is enmeshed, and man's place in it, are clearly—and beautifully—described in the poems of Walt Whitman. A great deal about the interplay of the physical features of the environment and the creatures that inhabit it can be learned from Moby Dick. Mark Twain is not only a marvelous source of wisdom about the nature of the environment of the United States from the Mississippi westward, but also a rather incisive critic of the irrelevance of science which loses connection to the realities of life. As the critic Leo Marx reminds us, "Anyone familiar with the work of the classic American writers (I am thinking of men like Cooper, Emerson, Thoreau, Melville, Whitman, and Mark Twain) is likely to have developed an interest in what we recently have learned to call ecology."
Unfortunately, this literary heritage has not been enough to save us from ecologi- 40 cal disaster. After all, every American technician, industrialist, agriculturalist, or public official who has condoned or participated in the assault on the environment has read at least some of Cooper, Emerson, Thoreau, Melville, Whitman, and Mark Twain. Many of them are campers, bird-watchers, or avid fishermen, and therefore to some degree personally aware of the natural processes that the science of ecology hopes to elucidate. Nevertheless, most of them were taken unawares by the environmental crisis, failing to understand, apparently, that Thoreau's woods, Mark Twain's rivers, and Melville's oceans are today under attack.
The rising miasma of pollution has helped us to achieve this understanding. For, in Leo Marx's5 words, "The current environmental crisis has in a sense put a literal, factual, often quantifiable base under this poetic idea [i.e., the need for human harmony with nature]." This is perhaps the major value of the effort to show that the simple generalizations which have already emerged from perceptive human contact with the natural world have a valid base in the facts and principles of a science, ecology. Thus linked to science, these ideas become tools for restoring the damage inflicted on nature by the environmental crisis.
In the woods around Walden Pond or on the reaches of the Mississippi, most of the information needed to understand the natural world can be gained by personal
5. Leo Marx: American literary and cultural critic (b. 1919) and author of The Machine in the Garden (1964).
experience. In the world of nuclear bombs, smog, and foul water, environmental
understanding needs help from the scientist.
UNDERSTANDING THE TEXT
Summarize Commoner's four laws of ecology in your own words. What are these laws? Are they provable and absolute the way that the laws of physics are?
How does Commoner define "cybernetics"? What is the connection between a cybernetic system and an ecosystem?
What keeps ecosystems in balance? Is it possible for an ecosystem to become so unbalanced that it stops functioning? How?
What does Commoner mean by "eutrophication"? How can it contribute to the collapse of an ecosystem?
What determines the amount of stress that a system can absorb? What happens when a system is no longer able to absorb stress?
Why does Commoner say that there is no such thing as waste? What happens to the materials that we commonly refer to as waste substances?