Surviving the environmental problems of our own making and living with our evolutionary baggage will be humankind's immediate challenge over the next several millennium.
Noel T. Boaz, a scientist, is Professor of Anatomy, Ross University School of Medicine. He is the author of Evolving Health, Eco Homo and Quarry: Closing in on the Missing Link. Noel Boez writes here about human evolution and some of the problems for sustaining the species and recommends some life style changes for all of us, including another look at T. Robert (Bob) Malthus' theory of overpopulation.
The theory around overpopulation has been used to justify a prejudice that poor people have too many children. It suggests that overproduction of children and the inability of resources to keep up with the rising human population implies an irresponsibility on the part of poor people not to have fewer children. Malthus suggested the family size of the lower class ought to be regulated such that poor families do not produce more children than they can support.
Dr. Frank W. Elwell, author of the book, "A Commentary on Malthus 1798 Essay on Population as Social Theory (Mellen Press, 2001) and other books, whose academic specialty include social evolution, industrialization, cultural ecology, and social theory says Mathus is misunderstood.
He writes that
both capitalists and communists hate him. "One reason that he is so thoroughly misunderstood has to do with the political ramifications of his arguments. Communists and socialists hate Malthus because he argued that inequality is rooted in the very nature of mans relationship to the environment, that mere structural reform could never attain a just and equal society. Capitalists and conservatives condemn him because he seemingly refutes the possibility of unending industrial progress."Noel Boez says that Malthus was right.There is enough in the world for all human need,
there is not enough in the world for human greedSurvival depends on a more equitable distribution of resources, goods and services, but we have already seen the consequences of overusing the world's petroleum and impending oil depletion and until we take a more holistic approach to availability of resources and undertake conservation and development of renewable resources and grow food for use not for profits we will have deficiencies and eventually run out of food, water, clean air and energy. While reversing the worse abuses of mal-distribution may help it cannot truly create just and egalitarian societies with the pressure of increased population growth and it is this scientist's view that some component of the Malthus argument is useful and my view is if we accept that position we can still apply to it the class nature of resource use, to resolve uneven distribution, but also including conservation and development of alternatives and a check on human population growth to insure the survival of our species (if it really matters?).
Hank Roth
PRESENT AND FUTURE HUMAN EVOLUTION
by Noel T. Boaz
There is a widespread belief that in the modern world human evolution has ended, that it is only a thing of the past. The origin of this idea is probably the belief that modern society is so powerfully controlling of human destiny that it has overcome all constraints of nature. This is incorrect. So long as there are birth and death, there will be varying degrees of reproductive success among people, differential survival of offspring, different degrees of access to food and other resources for life, and a range of variation in the human population. Natural selection will continue to work. As we have seen, human culture, the basis for the multifarious societies in which human beings live and reproduce, evolved out of the natural realm and is a product of natural selection. Human culture is a powerful adaptive force in its own right, but only if it ultimately serves natural selection. What nature gives it can take away.
(...)
It is important to frame the problem of human--environmental interaction in appropriately humble terms. We may destroy the "world around us" for ourselves and we may even take down several species with us to extinction, but it is not within human power to literally destroy the earth. We are far too puny to do that. Our most powerful nuclear weapons would only leave a few minuscule pock mocks in the earth's crust where our major cities had been, and within a few centuries even these would be erased by erosion. Humans and their highly touted culture would be gone, but other species--bacteria, plants, insects, and even probably most vertebrates--would remain and continue to evolve. The earth would survive just fine. So we are not discussing altruistic "save the earth" campaigns. We are discussing "save the earth for us."
THE GLOBAL PROBLEM OF OVERPOPULATION
In one of the most important cross-disciplinary fertilizations in science, the ideas of economist Thomas Malthus gave naturalist Charles Darwin some of the working concepts for the theory of natural selection, published in Darwin Origin of Species in 1859. Malthus's formulation was simple. Populations increase geometrically, graphing to an ever-increasing upward curve, while the food resources on which they depend increase only arithmetically, graphing out to an upward-sloping straight line. As population size increases and the lines on the graph diverge, the greater the disparity between the haves and the have-nots. Malthus could only see suffering, famine, disease, and war in the human future unless sexual continence could curb human population growth. Eventually there is an equilibrium point at which the rate of production of offspring equals the death rate, and it is at this point that Malthus's upward curve of population growth flattens out to the top part of an S. Malthus's formulation did not posit any absolute maximum size for population. Rather, he pointed out the critial relationship between population size and resources. Malthusian disaster can therefore occur not only when the population increases past a point at which resources can support it but can also strike when resources shrink relative to the number of people in a static population.
If world history is any guide, Malthus was essentially correct. Large-scale depopulation has occurred in the face of disease, such as the European "Black Death" of the fourteenth century when an estimated 75 million people, between one quarter and one half of the population, died. The Black Death (bubonic plague) was caused by a bacterium, Yersinia pestis, that was spread to humans by fleas that had bitten infected rats, and also by direct transmission from individuals in whom the infection had spread to the lungs. High population density in cities greatly facilitated the spread of the disease, although an environmentally induced increase in the rodent populations in which the disease was endemic has been suggested as the proximate cause of the epidemic.
An earlier epidemic of plague in the Middle East, Europe, and Asia in the sixth century is estimated to have wiped out 100 million people, perhaps one fourth of the world's population at that time. Smallpox, an introduced European disease, decimated the native American Indian population in eastern North America during the eighteenth century. Beyond the reach of history but still recorded in our genes is the terrible toll exacted when malaria became endemic to Africa, leading to protection by the sickle cell trait. A similar defense evolved against cholera in European populations, leading to a genetically mediated immunity to cholera toxin by the cystic fibrosis gene. *
* Individuals infected with the malarial parasite are protected from the disease by
sickling of the red blood cells, which are removed from the blood by the immune system along
with the parasites. But if all the individual's cells are sickled, then sickle cell anemia
results, a fatal genetic disease if left untreated. There is thus a "balanced polymorphism"
in African populations between death from malaria and death from sickle cell anemia, a
lasting legacy of the natural selection resulting from this disease. A similar relationship
exists in European populations between cholera and cystic fibrosis--individuals who have one
gene for cystic fibrosis do not have this genetic disease and are protected from the
infectious disease, cholera, whereas individuals with two genes are afflicted with cystic
fibrosis.
Increase in population numbers and greater population density are both implicated in the spread of disease. Malaria, for example, became widepread in Africa only after agriculture cleared the land and villages increased in size, both of which established standing pools of water, which are breeding sites for mosquitoes, the vectors of the disease. Cholera is caused by an intestinal bacterium (Vibrio cholerae) that is spread through contamination of a common water source by feces. It is directly related to population density. War, another Malthusian population check, has been an important force of depopulation. World War II led to the deaths of 15 to 20 million combatants and over 25 million noncombatants, not including the 6 million Jews who died in the Holocaust. If we think that the Nazi Holocaust was a one-time event, we need only look to the decades-long Hutu-Tutsi conflict in Rwanda or the "ethnic cleansing" campaigns of the Balkan civil wars, which have killed hundreds of thousands and displaced millions.
Overpopulation has a direct connection to war, usually expressed in terms of economic distress. Hitler's rise to power after the Depression on a platform of xenophobia and economic stability would have been impossible without the widespread feeling in Germany that there were too many people and too few resources. Rwanda's population density is the highest in Africa and competition for arable land is intense. The economic distress of Bosnia, Croatia, and Serbia after the collapse of the Soviet and Eastern European socialist economies is the proximate cause of the civil wars that have riddled the region.
Famine also occurs throughout the world with regularity. The failure of the potato crop in Ireland in 1841 led to widespread starvation and the death of some 1.5 million people. Drought in Ethiopia in 1990-91 affected some 7 million people and resulted in the deaths of uncounted hundreds of thousands. Famine occurs when the population is already near the ecological carrying capacity of the land. With one environmental perturbation such as a fungus (Phytophthora infectans) affecting one plant (the potato) or a relatively low rainfall over a two-year period that does not allow herds on already overgrazed lands to survive, whole-scale starvation can result.
(...)
The threat posed by the ever-increasing world population means in Malthusian terms increased suffering, more widespread disease, war, and famine, not only for the affected population directly but for all of us indirectly as environmental degradation, pollution, disease, lowered economic productivity, and conflict can now easily spread globally. World population now stands at 5.3 billion, and one estimate suggests that if birth rates are brought into line with death rates, world population will level off at between 8 and 9 billion by the year 2075. But another futurological study by the United Nations suggests much higher numbers--between 11.3 and 14 billion people--by the end of the twenty-first century.
Decreasing birth rates worldwide, rather than waiting for Malthusian population checks, is obviously the best solution, and we have seen that governmental actions have been only marginally successful in legislating compliance.
(...)
THE URBAN HUMAN ZOO
Darwin pointed out over a century ago that in many respects, such as in the loss of our extrinsic ear muscles, human beings resemble domesticated animals. Except for a few adolescent party tricks, our extrinsic ear muscles are totally useless. They are like the floppy ears of sheep, goats, cows, many domestic dogs, and even some breeds of rabbits that lost the ability to respond to the slightest crackling of a twig at the approach of danger. Instead, humans protect domesticated animals from predators and at the same time become their primary selective agents. Darwin studied this and many other examples of artificial selection in order to gain insight into how natural selection worked. He thought that humans resembled domesticated animals because people had essentially domesticated themselves--by removing the usual forces of natural selection and replacing them with the forces of artificial selection. Today we would explain this self-domestication of humans as adaptation to a cultural ecological niche--humans having adapted to culture, which in turn adapts to the environment.
Zoologist Desmond Morris took Darwin's idea further. Morris observed that human beings resemble not so much domesticated animals as caged animals. In The Human Zoo he argued that humans murder members of their own species, have a heightened sexuality, are overly aggressive, become obese, and suffer from neuroses, much the same as wild animals confined in zoos. Implicit in Morris's message was that the urban habitats in which modern humankind finds itself today are not its aboriginal or optimum environments. If this is true, how did such a discordance ever come about?
Ever since the Neolithic Revolution some 10,000 years ago in Mesopotamia and the Nile Valley, when people started practicing agriculture, animal husbandry, and the control of permanent water sources, they began to congregate together in knots of population and closely spaced structures known as villages, towns, and cities. At first this adaptation allowed the coexistence of traditional hunter--gatherer life ways beyond the confines of the early cities and their fields. But as the Middle East was, and still is, a region of marginally adequate precipitation, progressive growth of population in the cities contributed to growing herds, overgrazing, loss of topsoil, deforestation, and killing off of the local wild animals. Soon there was no more place for hunters and gatherers.
Cities found permanent sources of water and sent out tentacles of trade that allowed them to survive and continue to grow even though they were surrounded by wasteland. Essential to their success was the growth of regional economies based on trade. Cities were able to attract the "peasants" from the hinterlands with the promise of a part of this wealth, a pattern of population movement that has continued to the present day in most countries of the world.
Accompanying people in this move into the city were generally lowered standards of living, a smaller living space, less varied diet, a greater chance of infectious disease, widespread prevalence of nutritional deficiencies, a slower growth rate for children, and a much higher chance of crime. We can accurately date the onset of urban living in the archaeological record by the decrease in people's body sizes and the increased incidence of disease, as indi- cated by their bones. With the many drawbacks to life in the city, why reasonable people would choose to move from the open countryside to such a place is mystifying.
The phenomenal growth of cities over the last 10,000 years attests to the extraordinary power of culture in directing and affecting human behavior. Cities with their concentrated populations become cauldrons of cultural activity, in turn spinning off economic productivity, political activity, and excitement. For a primate whose brain is prewired for cultural stimulation, a city becomes a mesmerizing population magnet. But, ecologically, cities are a bad idea.
The first urban environments with their increased population densities went along with increased concentrations of human waste and garbage. As cities have grown they have had to deal with these basic public sanitation problems, or else face extinction. But as anyone who has seen the havoc resulting from a weeklong garbage strike in New York can attest, it is a fragile "solution," and one without a long-term future. Modern cities deal with their waste with their water treatment plants, sanitation systems, garbage collection systems, and landfills--all solutions in the short term. But urban environments have been around long enough now to have created some long-term ecological problems from the wastes that they have generated.
Modern cities offer much poorer living conditions than nonurban environments. Because of the density of buildings there is a decrease in incident solar radiation and few open spaces with vegetation. Visibility is decreased and noise pollution is at its worst in cities. Horizontal wind speed is decreased in cities, tending to trap the noxious emissions of motor vehicles. Because cities also have numerous "heat islands," there is increased convection at the city center, which brings in even more pollution from the outskirts. Cities are hotter and more humid, with a tendency for more fog, cloudiness, and precipitation than the surrounding countryside. When particulate air pollution combines with fog to produce smog, a health hazard exists. In December 1952, for example, London experienced a particularly lethal smog that claimed the lives of 3,500 to 4,000 inhabitants.
People, however, do not need to die or even to get sick to become convinced that many cities are not fit for human life. In many large cities around the world, those who can, leave, and move to the suburbs. They may still commute into the city for work, but their home environment outside the city has cleaner air, drinkable water, some open space with trees and grass, reliable public utilities, good schools, and a crime situation that is under control. Lionel Tiger in The Pursuit of Pleasure calls all these "evolutionary entitlements" of every human being, an innate part of our ancestral adaptation to which all of us should have free access. But what if you can't leave the city?
Urban riots. They happen when you're angry and frustrated at not getting what any normal human being should have to live. You're hot. You can't breathe. It would be great to have a place to go swimming. Somebody manages to turn on a fire hydrant in the street that cools everybody down. But then the cops come and turn it off. Suddenly it's too much, and the situation explodes. It doesn't seem to make any sense, but it happens, with predictable and terrible regularity.
Economists and news commentators shake their heads in bewilderment as the evening news shows the violence, looting, and burning in yet another city center. "Why," they ask, "do people burn their own neighborhoods, the businesses in which they work, and their schools?" The economist being interviewed by a newscaster cannot make any sense of it. Once he has mouthed the required platitudes about depressed economic outlooks for our cities, the need for greater education and self-help programs in the ghetto, and how the government needs to do something, he concludes that City X has just dug itself into a deeper hole. Then he is off-camera. As he leaves the studio, the economist think to himself, "I really don't understand it. These people act as if they are owed something, as if they deserve something. You only get things in our economic system if you work for them, and these people have obviously not worked hard enough. Instead of working within the system, they are actually trying to tear it down. Crazy."
But it's not. Illogical, yes. Economically unproductive, yes. But whole segments of a population do not go "crazy." Rioting is a primitive lashing out against the forced confinement in an urban habitat that does not meet even basic human needs. Perhaps Tiger is right in paraphrasing Thomas Jefferson. Perhaps there are "inalienable rights" to a decent human environment born of our evolutionary history. Perhaps that is what the rioters feel that they are owed but cannot put a name to. Try to explain that one to Jesse Helms.
FOULING THE NEST: POLLUTION AND DISEASE
Chimpanzees and gorillas build "nests" of vegetation every night in which to sleep. It initially surprised primatologists to observe that these close relatives of humans frequently defecate in their nests rather than leave them at night. Assuming that this was the primitive behavior, anthropologists have theorized about when and how humans became fastidious. An increased level of personal hygeine may have come about as soon as humans became more sedentary. Apes move their nests every night, so it hardly makes a lot of sense for them to put effort into keeping them clean. Humans, on the other hand, at some point developed a "home base," to use archaeologist Glynn Isaac's term. They would forage and hunt from this base camp and return there every day. It would make evolutionary sense to keep the home base, the immediate surroundings in which one was living, clean and relatively free of offal, which would attract scavengers, insects, and disease.
Most likely this behavior was not a conscious decision; things just "smelled bad" and were removed. Human hairlessness may have evolved at this same time as an evolutionary response to warding off skin parasites such as fleas and lice. These animals have a reproductive cycle of about two weeks and would be left far behind in abandoned ape nests, but they would have time to lay eggs and reproduce if humans were staying around in one place for two weeks or more. However it evolved, humans have a strong concept of their own personal and group space--their home base--and they keep it tidy.
The archaeological evidence for home bases is compelling and quite ancient. Tools and bone refuse at Koobi Fora, Kenya, and Olduvai, Tanzania, attest to repeated occupation of one site for relatively long periods of time. Humans thus added on a dimension of "personal space" that apes did not have. In addition to their "nest," which we in English call a "bed," there was a larger area that was kept clean and free of refuse. We might refer to this space by the familiar term "house" but it could also be an apartment, a cave, a hut, or a tent. At Olduvai site DK, some 1.5 million years old, there is the remnant of a stone circle that is widely believed to be the archaeological remains of the first structure (maybe a hut but also possibly a widebreak, a game hide, or something else). Outside this space there is a peripheral space that might or might not be considered part of the "house"--a "yard," perhaps. Most cultures also keep this space clean even though it is space that may be shared with other members of the group. Then there is the space "outside." Here garbage is thrown. I have a vivid image of a woman in a rural village in Zaire one morning sweeping the red dirt space outside her and her neighbors' huts clean of the slightest bit of litter, but she stopped sweeping at a razor-sharp line of demarcation with the surrounding luxuriant green foliage of the forest. This was her dividing line between "inside" and "outside" spaces.
I have been struck in cultures around the world at the varying degrees to which "insideness" and "outsideness" are applied. In Appalachia one's yard is definitely "outside" and becomes a dumping ground for old cars, washing machines, and assorted junk. In the Middle East, however, one's walled garden or courtyard is a sacrosanct space that is kept spotless. Step into the street, though, and one is apt to trip over an assortment of refuse, dead animals, and old tires. The public thoroughfares are considered "outside" and thus their cleanliness is paid no heed. Western Europeans, on the other hand, consider that urban areas are also to be kept clean and free from litter. Their definition of "outside" tends to mean "away from people." I have been amazed at my continental European colleagues in the field who nonchalantly throw an empty soft drink can onto the ground in the midst of the unspoiled splendor of the African savanna. They don't do it again if they see me picking up after them, because they had thought it didn't matter. Nobody lives there, nobody would ever see the can, and I don't live here, so what difference does it make? For 5.5 billion humans descended from nest-fouling apes it makes a tremendous difference. But we can learn to do better.
Pollution is basically an "inside--outside" problem. People define some place as culturally "outside" and consider it as appropriate for dumping waste. In the evolutionary past, when hominid population densities were low,...and the global population only numbered a few hundred thousand to a few million, this time-honored approach worked fine. A relatively sedentary hominid group avoided close proximity to waste and thus kept the scavengers, insects, and disease at bay. Biodegradation took care of what was thrown "outside." But as humans have spread over the earth's surface and population has climbed up in a series of explosive bursts after the end of the Pleistocene, it has become more and more difficult to find a place that is "outside."
Love Canal is a place in upstate New York that a local government defined as "outside." Tons of toxic chemical waste were dumped in a landfill there. Years later the site was bulldozed, relandscaped, and turned into suburban homes by real estate developers. Love Canel was redefined culturally as "inside" but unfortunately the chemicals did not know that. They infiltrated the drinking water and food of the residents and made them sick, deformed their babies, and caused some of them to die of cancers.
Minamata Bay is in Japan, and because it was in the sea, a chemical company decided that it was "outside." The company disposed of large amounts of waste containing mercury in the bay. Fish living in the bay ingested the mercury. People eating the fish became poisoned with the excess mercury and, worst of all, pregnant women gave birth to terribly deformed and severely mentally impaired children. Doctors termed this new malformation "Minamata disease, but it was not really a disease; it was poisoning.
The attitude that "outside" could mean far away from people was tried out by the French government. It conducted atmospheric nuclear tests in the South Pacific, about as far from France as one can get. Unfortunately, other people do live there. The nuclear contamination in the form of an isotope of strontium, strontium 90, drifted over the Marshall Islands. Strontium 90 is absorbed into bone and stored there much the same as is calcium. So what appeared to be very small amounts of the contaminant in the environment and of no real concern became concentrated in people's bodies. As the radioactive strontium decayed and emitted DNA-damaging radiation, it caused the developing white blood cells in the bone marrow to begin dividing uncontrollably. This is known as leukemia. Marshall Islanders began dying of leukemia and suffering from skin cancer, where there had been a low incidence before.
The solution to pollution is to culturally define the entire earth as "inside." Then humans will have their inherited and culturally passed-down approach to environmental tidiness on the side of conservation. Our ancient hominid behavior of simply throwing things away so we do not see them anymore will no longer work. Unfortunately, as we have grown to understand the hard way, we can no longer throw things away entirely. If we can somehow convince everyone that the whole earth is "inside" our cultural space, the technology exists or can be developed for long-term ecologically sustainable waste disposal and prevention of pollution. Early hominids transported to the present would probably opt to blast our earth-generated garbage to the next higher "outside" space, actually outer space. In addition to just extending earth's pollution problems to nearby parts of our solar system, this "solution" would eventually deplete the natural resources on earth that went into producing the garbage in the first place.
The cultural part is the hard part. If the global "we"--ourselves and the next several generations--can become more inclusive of other cultures, traditions, and "races," then there is a hope that we can forestall being overrun by mounting piles of garbage, poisoned air and water, and increasing mortality from polluting agents. If not, we will fall back into the ancient pattern of competition and replacement of populations characteristic of human evolution during the Pleistocene. This is the all-too-familiar ethnocentric, winnertake-all, rapacious adaptation of primitive culture. The former approach is more adaptive because world culture would gain from all its components, ensuring a maximum supply of accumulated wisdom in adapting to the environment. One is tempted to say that this is also the more intelligent approach, but intelligence is not the issue here. Humans have been of the same intelligence since the end of the Pleistocene, only 10,000 years ago, so one would be more accurate in commending a multicultural approach to solving world pollution problems on the basis of it being "more informed."
ENDANGERED SPECIES: THE CANARIES OF A DYING WORLD
Coal miners used to take a caged canary down into the earth with them to monitor the environment. If the oxygen became depleted in the poorly ventilated mine shafts, the canary would stop singing or die, since its higher metabolism required a higher concentration of oxygen in the air. The miners then knew they had only a short time to get out of the mine shaft or they themselves would die.
In the larger macrocosm of world environment, species of animals and plants represent coal-mine canaries. When they die it indicates that something is going wrong in our environment. The only difference it that we do not have anywhere else to go.
The conservation movement has raised the preservation of species diversity to a goal unto itself. But the human species is really too selfish for that. Nonhuman species of animals or plants will never be preserved solely on the basis of their intrinsic right to exist, especially in the face of human needs. For example, the most ardent conservationist will hit a brick wall in arguing with a Montana sheep farmer who shoots an endangered wolf because it has just eaten one of his newborn lambs. And even the most proenvironment yuppie ranchers of central Oregon will call in the county animal control unit when a rare and endangered mountain lion carries off one of their prized llamas or emus. Conservationist groups attempt then to create a human character for their endangered species, to carve out a cultural identity. In order to popularize their efforts, they totemize their animals and make them part of human culture-baby seal plush toys are sent to contributors who want to stop the killing of fur seals, save-the-whale educators drive to schools in an old Volkswagen van painted like a whale, and virtually every group produces that ubiquitous identifying badge of cultural identity, a T-shirt, with a brightly screen-printed image of "their" endangered species on it. These are their totems, identifying them with a common cultural cause, conferring group membership, and giving their lives meaning.
There are some unspoken rules for which animal species get this sort of human attention. First of all, the species cannot be an ecological competitor. There are no foundations set up to ensure that the rat and the cockroach do not go extinct. Some species, like the mountain lion, wolf, and coyote, fall into an ambiguous category because they are ecological competitors only to a segment of the human population, ranchers in particular. Another rule is that the species to be conserved cannot be a human parasite. No one cares to prevent the extinction of the flea, the tick, or the liver fluke. A sine qua non of human conservation of a species then is lack of ecological competition.
It is not absolutely essential for its chances of preservation, but it helps if a species is more closely related to humans. Mammals, especially the intelligent, beautiful, and graceful ones like carnivores, primates, and sea mammals, get the lions' share of the conservation effort. Many birds, which can be beautiful and graceful if not intelligent, figure fairly prominently in conservation efforts. But there are twenty-two species of clams and thirty species of fish that are endangered in the United States, and despite the fact that their numbers reflect the cleanliness of human water resources-an essential human resource-campaigns to save them are few and far between. The endangered snail darter, a small fish living in the Tennessee River drainage system, is one exception. Its preservation in 1977 became the focal point of a major campaign to prevent the construction of a new dam. But in general nonmammals-reptiles, amphibians, fish, and invertebrates--are difficult species for people to identify with.
If scaly, slimy, and many-legged species of animals do not fare well with human conservation efforts, the immobile but animate world of plants is even more shunned. It is difficult to hug a threatened plant and have it gaze back at us appreciatively (as it is a baby tiger, but we can imagine it). Plants are also not cute, warm, and soft to touch. They just fall too far outside the range of our mammalian protective instincts. Only the majestic California redwoods have somehow transcended this plant-animal divide and command widespread reverence. But for most plants the approach to their conservation has to be on an intellectual and scientific plane.
Conservationists working to preserve tropical plants have found that the most effective approach is to aggregate a large number of species together into a unique and endangered habitat-the rain forest, for example. This way it can be shown that a large number of species growing together help to prevent such human ecological disasters as sod erosion or silting up of rivers and lakes. Appeals for the preservation of species diversity in the rain forest have also been based on the possible medicinal uses, again of potential human benefit, that may be found in single species of plants there. Again, plants will not be the subjects of conservation if they exist in a competitive ecological relationship with humans. No one has a particularly soft spot for poison ivy, for example. This and other species are culturally defined as "weeds" and are usually locally eradicated if possible. Conservation of species diversity on earth is clearly of adaptive significance for human beings, simply because a diversity of species indicates an equilibrium of natural forces the same as those under which human evolution progressed to its present state. These conditions are most compatible with human health and well-being. There are also clear human uses for many wild species of organisms. As objects of study they provide knowledge of the evolution of life, instruct us in alternative ways of adapting to the environment, and can provide insights into environmental quality when used as an indicator species of pollution. Wild plants, in addition to their contribution to the makeup of their communities, can both serve as possible sources of future medicines and as possible future food plants.
In addition to the pragmatic reasons, some conservation of species closely related to humans is clearly more emotional. "Cute" species, such as the Chinese panda, receive an inordinate amount of attention, out of all proportion to their ecological significance. Evolutionarily, we can explain this behavior only as an extension of human feelings of caring toward intraspecific infants and juveniles, typified by the rounded features, soft contours, and short extremities that we consider "cute." Extending this same attitude toward less cute species will benefit us immensely in improving the eventual quality of our future environment.
HUMANS, THE INSATIABLE ENERGY EXTRACTORS
Energy extraction for humans is a tool for expanding the usable range of resources in their environment and to transform parts of the environment to their own purposes. When humans began using fire, a type of rapid oxidation that produces heat and light, they began to harness extracorporeal sources of energy. This control of energy provided the basis for humans to expand and adapt to the harsh environments of the Pleistocene. Fire was an important part of hunting (in driving game) and in the later development of agriculture, in that it was the major way that land was and is cleared in "slash-and-burn" agriculture.
Fire allowed food to be cooked. Previously inedibly tough foods, such as meat, and previously toxic foods, such as numerous alkaloid-containing plants, could now be ingested, broadening humans' dietary range. Fire gave humans a competitive interspecific edge over other animal species, it provided fight at night, and it provided heat when humans moved north out of Africa. In more recent times, controlled use of fire in generating steam and then in the internal combustion engine ushered in the Industrial Revolution and the modern mechanistic age. Fire has served humankind well for over a million years, but there has been a price.
Because fire consumes oxygen and produces carbon dioxide and other chemicals resulting from the oxidation of its fuel, it contributes to changes in the atmosphere. From the beginning of humans' controlled use of fire in the early Pleistocene to only a few hundred years ago, the human contribution to fire's effect on the earth's atmosphere was infinitesimal compared to the effects of natural fires. Even today, forest fires and other naturally occurring fires are listed as major contributors to particulate and gaseous air pollution.
The major producers of today's air pollution, however, are of human origin. Automobile exhaust, emissions from industrial manufacturing, and smoke from power plants that burn fossil fuels are the three biggest contributors. Air pollution breaks down into the constituents of carbon monoxide, a poisonous gas; sulfur dioxide and nitrous dioxide, which produce corrosive sulfuric acid and nitric acid; particulate matter such as airborne carbon; and hydrocarbons from unburned fossil fuels capable of strong oxidation when subjected to reaction with ultraviolet radiation from the sun. Acid rain resulting from air pollution acts to kill acid-sensitive plants. Air pollution directly irritates our eyes and throats, and as already noted, can be fatal under some circimstances.
An indirect effect of air pollution has occupied much attention in the last decade, and that is the so-called "greenhouse effect." A greenhouse is typically a hot, high-humidity environment ideal for plants. Sunlight enters through the glass roof and walls but its radiant heat cannot leave. Carbon dioxide in the earth's atmosphere works much the same way as the glass in a greenhouse. It lets the sun through but then traps the radiant heat on the earth's surface. Since the Industrial Revolution the amount of carbon dioxide in the earth's atmosphere from burning of fossil fuels--coal, oil, and natural gas--has steadily risen. One estimate based on a study in Hawaii indicated that carbon dioxide content was increasing 0.02 percent per year.
In addition to higher average temperatures year-round, an increasing level of carbon dioxide would contribute to a substantial rise in sea level as increasing amounts of polar and glacier ice melt, and the precipitation regimes driven by temperature differences around the world, would change. If the greenhouse effect hit with full force, many coastal cities of the world and many trillions of dollars in personal property would soon be under water, and huge food-producing parts of the world could experience near-desert aridity.
(...)
FUTURE HUMAN EVOLUTION: PREDICTING THE UNPREDICTABLE
There is an interesting paradox in popular views of current and future human evolution. One view is that change has become so rapid and so intrinsic to the human adaptation that almost anything is possible in the future. If one is an optimist, this can mean unbridled possibilities for technological progress and improvement of our quality of life. If one is a pessimist, then there will be almost infinite possibilities for human beings to destroy themselves and the parts of the planet on which they live, taking many other species with them. These opinions of rapid future human evolution are usually reserved for cultural evolution.
Another view of the future is that with modern medicine, natural selection has been slowed down to a standstill in terms of physical and biological evolution of the human species. Where once whole populations were decimated by infectious disease, today in many parts of the world antibiotics, public sanitation, and effective preventive medicine have reduced the mortality figures to almost nil. Parasitic diseases, the bane of human existence for untold millennia, have been virtually wiped out in the developed world as well. Trauma, which in the past was a major killer of human beings, is now effectively dealt with in the emergency rooms of hospitals or even en route by highly trained ambulance crews. Hemorrhaging can be quickly staunched, shock can be effectively treated, ingested poisons can be removed or neutralized, and body fluids restored. With these three major cullers of the human population--infectious disease, parasitic disease, and trauma--taken out of the picture, some argue that human biological evolution has largely stopped.
Both views are erroneous. Culture in fact is an ancient adaptation that changes its content but not its modus operandi from generation to generation. There will be a tendency for people to view their own ideas as right and correct far into the future. Ethnocentrism is a pan-human universal. We will either use our advanced brains to figure out that our ethnocentrism needs to extend to the entire human species, or one ethnocentric group will hold sway and eventually preempt the remaining global natural resources for itself, allowing the rest of the species to go to extinction. We can hope that the former path is chosen. But if human evolution and world history are any guides, the latter possibility is unfortunately just as likely. Our vaunted view of modern medicine and its presumed powerful effect on human evolution is vastly overstated. It is true that people in the developed world no longer die of the same causes as people before the Neolithic Revolution. It is also true that average life expectancy is longer today than it was in prehistory. But these effects of modern medicine are extremely recent phenomenon, less than two centuries old. They have also been in effect in a limited minority of the world's population. Even more importantly, however, modern civilization confers, along with all its advantages, several decidedly disadvantageous disease states. These diseases, such as cancer, heart disease, and diabetes, are killers. They can strike down the young as well as the elderly, and they are clearly a major force in natural selection. These diseases are virtually unknown among hunter-gatherers, and we may presume among our prehistoric ancestors as well. We may deduce then that these diseases are largely the result of interaction between our bodies and our environment--the environment that culture has created for us.
This interaction is complex, for medical geneticists have discovered a number of oncogenes that also seem to have a formative influence on many cancers. We must remember, however, that these same genes may have functioned effectively or may have never been "turned on" in our ancient environments. Natural selection is and will be clearly at work at the cellular and biochemical levels in effecting biological change in the human species. Medicine at best can forestall some of these effects but cannot cancel them out.
Physical evolution of the human species is predictive only insofar as we can forecast what will allow humans to more effectively bear and transmit culture, our primary adaptation to the environment now and in the future. Our brain, then, may well enlarge secondarily to selection for increased intelligence. The trite view of the humans of the future as large-brained and puny-bodied beings may indeed be as accurate as we can be. Certainly, intelligence is at a selective premium now as in the past, worldwide.
One thing is certain about the future. Humans will be at the mercy of the environment, as they and their ancestors have been since the dawn of time. Advanced culture evolved in the late Pleistocene to keep up with an accelerating pace of environmental change. But as human population and the spinoffs of human activities have increasingly changed our world, both our physical and cultural means of adapting to environmental change have been pushed to their limits. To restore a balance, the pendulum of cultural change will have to shift back to a pattern consistent with our evolutionary adaptations: low population density, a demographic pattern very different from that of today's maladaptive urban centers; environments that meet human needs, even at the massive costs of construction, environmental cleanup, and technological innovation needed for that result; and a shared cultural identity within the global human population.
These results are not prescriptions for an ecologically ailing world. They are the ultimate results of natural selection, assuming continued human survival on earth, the relative slow rate of biological evolutionary change, the finite natural resources of the earth, and the heavy toll of human death and suffering exacted by an increasingly poisonous environment. Humans can take remedial steps themselves by directing their own cultural evolution, the preferable way--or natural selection will eventually do it for them, either crafting future human evolution as it has over the past 5 million years, or simply snuffing out another fleeting species, as it has done innumerable times over the last 2 billion years.
Environmentalism needs to be pragmatic but at the same time appropriately humble before the vastly superior power of nature. Pragmatic because we cannot expect humans, themselves a product of natural selection, to risk their survival and reproduction for the benefit of other species. Humble because a nonanthropocentric, long-term view also unambiguously shows that our survival as a species is ecologically linked with that of other species, and it is the only view that explains why we are up against a number of Thomas Malthus's checks on population growth. Other species, if allowed to survive, will not only function as indicators of environmental quality but their unique adaptations will be of great potential practical benefits to human beings in the future.
Unfortunately, the short-term, arrogant view is still prevalent. Essayist Charles Krauthammer, in an article entitled "Saving Nature, But Only for Man," (Time, June 17, 1991) wrote, "Nature is our ward. It is not our master. It is to be respected and even cultivated. But it is man's world. And when man has to choose between his well-being and that of nature, nature will have to accommodate." Mr. Krauthammer argues for oil drilling at the expense of the caribou in Alaska and lumbering at the expense of the spotted owl in Oregon, but his precepts are flawed. We are the wards of nature, not the other way around. Nature is our master. Mr. Krauthammer may conceive of Mother Nature as a benign granny in her rocking chair who deserves our respect, but whose directives do not carry the force of law. Here he is sadly mistaken if he thinks that her flinty and wizened gaze would even blink at the disappearance of so inconsequential and short-lived an organism as "man." Old she may be but woe to the species that trifles with her world. Others have described her as "nature red in tooth and claw."
Surviving the environmental problems of our own making and living with our evolutionary baggage will be humankind's immediate challenge over the next several millennia. If world culture evolves into an effective adaptive mechanism and it stays in synchrony with our biology, then we might be up for our next big environmental challenge.
The above was excerpted from the concluding chapter in "Eco Homo: How the Human Being Emerged from the Cataclysmic History of the Earth", a book by Noel T. Boaz - Basic Books, 1997, used here is in compliance with the Fair Use Doctrine for educational, research and discussion purposes in an effort to inform and advance the awareness and understanding in accordance with our progressive mission and Title 17 U.S.C. Section 107, Copyright Law
Hank Roth
More Related Content
All quotes are Fair Use for educational purposes
Title 17 U.S.C. Section 107, Copyright Law
Permalink: http://inyourface.info/ArT/Xi/Fu.shtml
Today is Friday, 18-May-2012 08:20:31 CDT
On the Internet since 1982