The Chemistry of Collapse

Many other animals seem to have a hormone-regulated response to environmental stress that switches their metabolism into a more economical mode whenever resources become scarce. Inevitably the energy-hungry processes of reproduction are the first to be targeted. For example, Australia’s kangaroos are able to put the development of their embryos on indefinite hold during drought by means of a unique, hormone-regulated phenomenon known as embryonic diapause. When the drought ends and food becomes readily available once more, the embryo resumes normal development. Wild populations of yellow baboons (Papio cynocephalus) have shown signs of hormone-regulated fertility decline during periods of social and environmental stress. The telltale hormonal signature of this process, first detected by endocrinologist Sam Wasser of the University of Washington, has also been identified in captive lowland gorillas, and in women. When persistent in women, it typically accounts for up to 10% of infertility and 25% of habitual abortion.

A similar hormonal signature with even more dramatic outcomes has been recognized in other species, notably snowshoe hares, lemmings, voles, rats, mice, and tree shrews. These animals, however, are more likely to become infertile during periods of social rather than environmental stress, and the primary governing factor seems to be population density. When the number of individuals rises to a certain level, a suite of internal factors, all hormone-regulated, appears to cut in, limiting fertility even where food resources remain unrestricted. This process has been shown to lead to a total cessation of reproduction in some cases, and occasionally leads to population extinction, although how this occurs is still poorly understood. The most startling feature of these collapses is that even when numbers had plummeted to the point that density was low and social stress was no longer a problem, instead of fertility rising and death rates falling to allow the population to recover, the decline accelerated. stop loss and take profit

General Adaptive Syndrome

This curious mechanism, originally called the general adaptive syndrome by Hans Seyle, who first noted it in 1936, has since been reported in several wild rodent species, but it is best documented in laboratory rats. In well-fed but extremely dense populations, social stress appears to trigger a broad spectrum of abnormal physiological responses such as glandular malfunction, inhibited sexual maturation, diminished ovulation and implantation, inadequate lactation, increased susceptibility to disease, and a sharp rise in infant mortality. Social responses include increased aggression, infanticide and cannibalism, curtailed reproduction, abandonment of unweaned how to make money from stock market in malaysia

Some researchers have suggested that this general adaptive syndrome may in fact play a far more important role than in availability of food in the regulation of mammal plagues, since a curious feature of most plague collapses in the wild is the continued availability of food and the scarcity of malnourished corpses. The evolutionary value of such a mechanism would be considerable. If a plague species could cull its numbers before it totally exhausted its food resources, then it would avoid the risk of degrading its environment to the point that its extinction was guaranteed.

Uninhibited by most of the estrous or seasonal factors that regulate reproduction rates in other mammal species, Homo sapiens seemed, until recently, to exhibit no trace of this syndrome and thus appeared to be biologically defenseless against exponential population growth. Wherever overcrowding coincided with high mortality rates (due to disease and malnutrition), fertility tended to accelerate, as parents tried to ensure against possible future family losses. Consequently, because of cultural factors and a peculiar ability to plan ahead, humans have tended to reproduce faster at precisely those times when the general adaptive syndrome might have been expected to come into play.

The Stress Connection

That appeared to be the case until the 1970s, when the East German scientist Gunter Dorner heard of the work of Selye and others on the physiological effects of social stress in laboratory rats and mice. Dorner had already spent much of his career investigating the role hormones such as estrogen and testosterone play in the development of the fetus, particularly in determining an individual’s sexual orientation. He was especially intrigued by reports that female rats subjected to severe social stress during pregnancy tended to produce male offspring that were attracted only to other male rats. Since he already knew that high stress levels experienced during pregnancy resulted in lower levels of male hormones in the womb, he decided to survey that section of the German population that had been born during and just after World War II to see if he could detect statistical evidence of the link between stress and sexuality in society at large. From the eight hundred homosexuals questioned in the survey, Dorner was able to determine that the homosexual birthrate (i.e., the percentage of homosexuals in the overall population) had indeed fluctuated according to the levels of stress suffered by women during pregnancy. More homosexuals had been born during the years of greatest social stress—during the last months of the conflict and those immediately following the war—than at any other time. In fact, two-thirds of the homosexual men and their mothers reported prebirth levels of stress ranging from “moderate” to “extreme,” and the stated causes included bombing, rape, and extreme anxiety. By contrast, only 10% of the heterosexuals in the control group reported unusual maternal stress during the prenatal period, and the mothers of these individuals reported only moderate prenatal stress.

Such a rise in the homosexual birthrate would of course have virtually no effect on the fertility of potential of the German population as a whole, but that such a stress-related reproductive control mechanism existed in Homo sapiens at all was significant. The global fertility decline that developed so unexpectedly during the past two decades clearly suggest that we may, after all, be subject to multitude of subtle, larger fertility controls very like those that control rodent plagues. All the hormonal signatures are there, although it is impossible to discern at this early stage which forms of stress are primarily responsible for decline. Changes in lifestyle, self-administered recreational drugs and food additives, increased exposure to chemical pollutants that imitate or inhibit the body’s sex hormones—any or all of these, plus others as yet undetected, might be the trigger. We will no doubt continue to equate our declining fertility with cultural success and attribute it to the empowerment of women, effective sex-education programs, and the general spread of literacy and better information. But if you switch off the cultural soundtrack and concentrate on the figures and the population graph, it all looks astonishingly like the end of a typical mammal plague—and the beginning of Selye’s general adaptive syndrome.

The Enemy Within

Hormones move in mysterious ways their wonders to perform. As the body’s chemical messengers bring about adaptive physiological responses to environmental change. How elegantly appropriate it would be if, in chaotic and fractal fashion, they served precisely the same purpose on a global scale. Even manufactured substances that mimic hormones, a rogue element as far as we are concerned, may effect adaptive physiological changes. These substances, often called “endocrine disrupters,” disturb normal sexual development in a wide variety of vertebrates, including humans, causing lower sperm counts, undeveloped or malformed genitalia, repeated failure of embryo implantation, and a rising incidence of ectopic pregnancies. They occur in a vast range of commercial products—pesticides, plastics, paints, inks, industrial detergents—and are released as breakdown products. The onslaught of such substances was first brought to public attention in 1962 by Rachel Carson in her momentous book Silent Spring. However, she considered only the toxicity of such chemicals and was unaware of their even more serious long-term hormonal consequences.

Most of the known offenders imitate estrogen, and the impact is therefore most noticeable in males. Under the feminizing influence of these estrogen mimics, genes that are responsible for the production of testosterone in males often fail to switch on. Extensive surveys of male fertility carried out in several developed countries (notably Denmark, Scotland, and France) suggest that the average number of sperm in the ejaculate of a normal man appears to have fallen by up to 50% during the past fifty years. Although the method of analysis used in the surveys was widely criticized, similar sperm count reductions and increasing signs of sexual dysfunction have been detected in several other vertebrates, especially rats, alligators, and birds, and these too seem to have been caused by exposure to artificially produced hormone mimics. The matter was finally put beyond reasonable doubt in January 1997 when a Finnish team compared testicular tissue (taken during postmortem examinations) from men who died suddenly either in 1981 or 1991. In that ten-year period the numbers of men who had normal testicular tissue and healthy sperm production had fallen by more than 50%. As increasing numbers of artificial endocrine become interwoven with whatever endogenous fertility inhibitors constitute the human version of the general adaptive syndrome, it seems likely that the current fertility decline will gradually accelerate.

Driven by such subtle and complex chemistry, our ultimate population decline is likely to remain both inexplicable and beyond remedy. We will see a gradual increase in the incident of biological social dysfunction, as well as rising levels of unproductive sexual behavior, such as homosexuality, lesbianism, and pedophilia, and an increasing heterosexual tendency to postpone or avoid parenthood. The natural fertility brakes are likely to become even more pervasive and pronounced as population pressure increases, social cohesion decays, and environmental degradation mounts.

Although the global fertility rate is now showing signs of significant decline, judging by the current rate of industrialization, our energy consumption will multiply by a factor of 2.5 by the year 2050. The technological factor of the I=PAT equation (Impact = Population x Activity x Technology) thereby promises to compensate for most of the decline in population growth. In other words, as far as the biosphere is concerned, it is almost as though human fertility were not declining at all, suggesting that something other than simple math is manipulating the equation to achieve this convenient end. To lay the blame on human culture is circular reasoning and provides no answer, so we are left facing the intriguing alternative that our predicament betrays the presence of some form of evolutionary genetic management system, mechanism that has automatically locked us into a cultural development that guarantees disaster; perhaps even a Gaian mechanism like the one proposed by Vernadsky, Lovelock, and Margulis.

Reg Morrison, “The Spirit in the Gene” pages 130-134.


- So let us recognize human mysticism for what it really is: the rusting Excalibur of our species, an old and vital streak of genetic madness that once rescued our kind from the brink of extinction, took us to the stars, and will run us through with due dispatch when our little play is done. Ultimately, I have no real argument with mysticism, nor even with the fear and ignorance on which it feeds. The frail, the fearful, and the foolish—these are my kind of animals.

Reg Morrison, last paragraph in “The Spirit in the Gene”.

Reviewed by Steven B. Kurtz