As the last forests are felled in forest strongholds like the Philippines and Ecuador, the decline of species will accelerate even more. In the world as a whole, extinction rates are already hundreds or thousands of times higher than before the coming of man. They cannot be balanced by new evolution in any period of time that has meaning for the human race. Why should we care? What difference does it make if some species are extinguished, if even half of all the species on earth disappear?
Let me count the ways. New sources of scientific information will be lost. Vast potential biological wealth will be destroyed. Still undeveloped medicines, crops, pharmaceuticals, timber fibers, pulp, soil-restoring vegetation, petroleum substitutes, and other products and amenities will never come to light. It is easy to overlook the services that conserved ecosystems provide humanity. They enrich the soil and create the very air we breathe.
Without these amenities, the remaining tenure on Earth of the human race would be nasty and brief. The life-sustaining matrix is built of green plants with legions of microorganisms and mostly small, obscure animals—in other words, weeds and bugs. They run the world precisely as we would wish it to be run, because humanity evolved within living communities and our bodily functions are finely adjusted to the idiosyncratic environment already created. Mother Earth, lately called Gaia, is no more than the commonality of organisms and the physical environment they maintain with each passing moment, an environment that will destabilize and turn lethal if the organisms are disturbed too much.
A near infinity of other mother planets can be envisioned, each with its own fauna and flora, all producing physical environments uncongenial to human life. To disregard the diversity of life is to risk catapulting ourselves into an alien environment.
We will have become like the pilot whales that inexplicably beach themselves on New England shores. Humanity coevolved with the rest of life on this particular planet; other worlds are not in our genes.
Because scientists have yet to put names on most kinds of organisms, and because they entertain only a vague idea of how ecosystems work, it is reckless to suppose that biodiversity can be diminished indefinitely without threatening humanity itself. Field studies show that as biodiversity is reduced, so is the quality of the services provided by ecosystems.
Edward O. Words: 16, Pages: Hayden, Chancellor, A. Staten Island J. Edward Meyer, B. Chappaqua R. Carlos Carballada, Chancellor Emeritus, B.
Rochester Adelaide L. Sanford, B. Hollis Saul B. Cohen, B. New Rochelle James C. Dawson, A. Peru Robert M. Bennett, B. Tonawanda Robert M. Johnson, B. Lloyd Harbor Peter M.
Pryor, B. Albany Anthony S. Bottar, B. Syracuse Merryl H. Tisch, B. New York Harold O. Levy, B. New York Ena L. Farley, B. Brockport Geraldine D. Chapey, B. Belle Harbor Ricardo E. Oquendo, B. Siegfried The State Education Department does not discriminate on the basis of age, color, religion, creed, disability, marital status, veteran status, national origin, race, gender, genetic predisposition or carrier status, or sexual orientation in its educational programs, services and activities.
Portions of this publication can be made available in a variety of formats, including Braille, large print or audiotape, upon request. This mass extinction, according to Wilson, is the most destructive global environmental change occurring at this time, and it is critical that we reverse the process. Following his keynote address at the New York State Museum, Wilson put together a manuscript based on the topics covered in his talk to be used as the basis of this educational book.
Although this manuscript was written in , the ideas presented are of great value and will continue to be important for many years to come. Edward Osborne Wilson is a world-renowned scientist and researcher. Over a career of nearly 50 years, Wilson has focused on a wide range of topics from population biology to sociobiology and, most recently, biodiversity issues. His major contributions to the field of myrmecology include the discovery of B i o l o g i c a l vii D i v e r s i t y pheromones that direct specific ant activities and the discovery of many previously unknown species of ants from around the world.
He has also begun to unravel and describe some of the complex social behaviors of these insects. He explains how all aspects of human well being are dependent on preserving the remaining biological resources of our world, and why we can no longer ignore increased extinction rates that are the result of anthropogenic activities. In the final pages of this book, Wilson offers recommendations and a multi-disciplinary approach for the successful conservation and use of biodiversity.
The BRI was created during a time of increasing awareness of the urgent need to preserve global and local biodiversity. Activities of the BRI are guided by an executive committee, which is appointed by the legislature and the governor of New York. By making this information readily available, natural resource managers will be better able to minimize potentially negative impacts on local biodiversity.
Ultimately, however, the successful conservation of biodiversity will also depend greatly upon increasing public concern and awareness—especially by future generations—of local and global biological diversity. In recognition of this situation, the BRI published this book with the intent of educating primarily high school students on the values of biodiversity.
However, considering the urgency and importance of the issues discussed, this book will, we believe, be of value to a much broader audience. We wish to acknowledge all the people who have assisted us in the publication of this book. Above all, we owe the most thanks to the author, Edward O. Wilson, who has graciously offered his writing to us. We are also grateful for all the effort Patricia Kernan has put into creating the drawings that illustrate the pages of this book and the cover.
Ronald J. Wilson In the northeastern United States, as in most of the remainder of the country, about one plant species in five is threatened with significant reduction in numbers or even with total extinction. Many people still ask the vexing question: Of what possible value, except to a few botanists, is a plant with a name like hairy beardtongue?
Why should money and effort be spent to save this and other bits of floristic esoterica? Let me tell the ways. Consider periwinkles of the genus Catharanthus, flowering plants that live on Madagascar, a great island off the East Coast of Africa. Inconspicuous in appearance, located all the way around the world, the six species of periwinkles would seem to be even less worthy of attention than beardtongues and louseworts. These anti-cancer substances are now the basis of an industry earning more than million dollars a year.
Ironically, the other five periwinkle species remain largely unexamined for their medical potential. One of them is near extinction due to the destruction of its habitat on Madagascar. A much higher percentage yield pharmaceuticals and other natural products of potential use as well as basic scientific information.
If we dismiss beardtongues and louseworts, we may be doing ourselves a considerable disservice. Simple prudence dictates that no species, however humble, should ever be allowed to go extinct if it is within the power of humanity to save it. Take another—even repugnant—example, the leech. We would certainly be better off without these miserable bloodsuckers, right? The medicinal leech of Europe has proved to be of great value to modern medicine.
To prevent the blood of its victims from clotting, it secretes a powerful anticoagulant called hirudin. This substance is used to treat contusions, thrombosis, hemorrhoids and other conditions in which clotting blood can be painful or dangerous.
Thousands of lives are saved annually by hirudin. The leech uses a second substance, the enzyme hyaluronidase, to disperse cells and hasten the penetration of hirudin. Surgeons adapt this material in the same way to spread injected drugs and anesthetics. Leeches also contain antibiotics and substances that enlarge the diameter of blood vessels, which might someday lead to a cure for migraine headaches. They are so much in demand that the European species is threatened by overcollecting in its natural habitat.
With the aid of other specialists my own special group is ants , I have estimated the total number of kinds of plants, animals, and microorganisms known to science to be about 1. But the actual number of kinds is estimated to fall somewhere between 10 million and 80 million, depending on the statistical method used and the degree of conservativeness on the part of the scientist making the estimate. In other words, we cannot say whether the figure is closer to 1 million, 10 million or million.
When scientists fail to make a measurement to the nearest order of magnitude, it is fair to surmise that the subject is still poorly known. The truth is that life on planet earth has only begun to be explored. Every time I go to a rainforest site in Central or South America, I find new species of ants within several hours of searching.
B i o l o g i c a l 4 D i v e r s i t y Some groups of organisms, such as fungi and mites small spider-like organisms that abound in the leaf litter and soil are so poorly studied that it is possible to find new species within a few miles of almost any locality in the United States, including the most densely populated urban areas.
Even new species of mammals still turn up occasionally. In the past several years, a new deer, a kind of muntjac, was found in western China, and a new monkey, the sun-tailed guenon, was discovered in Gabon. We know less about life on earth than we know about the surface of the moon and Mars—in part because far less money has been spent studying it.
Taxonomy, the study of classification and hence of biological diversity, has been allowed to dwindle, while other important fields such as space exploration and biomedical studies have flourished. Like glass-blowing and harpsichord manufacture, taxonomy of many kinds of organisms has been left in the hands of a small number of unappreciated specialists who have had few opportunities to train their successors.
To take one of hundreds of examples, two of the four most abundant groups of small animals of the soil are springtails and oribatid mites. Marvelously varied, having complex life cycles, and teeming by the millions in every acre of land, these tiny animals play vital ecological roles by consuming dead vegetable matter. Thus they help to drive the energy and materials cycles on which all of life depends. Yet there are only four specialists in the United States who can identify springtails—one is retired—and only one is an expert on oribatid mites.
The reason that so little is heard about these important organisms in the scientific literature and popular press is that there are so few people who know enough to write about them at any level. The general neglect of expertise in the face of overwhelming need and opportunity rebounds to the weakness of many other enterprises in science and education.
Museums are understaffed, with too few biologists to develop research collections and prepare exhibitions. Systematics, the branch of biology that employs taxonomy and the study of similarities among species to work out the evolution of groups of organisms, is able to address only a minute fraction of life. Biogeography, the analysis of the distribution of organisms, is similarly hobbled.
Some kinds of research may be held up indefinitely. As the Chinese say, the beginning of wisdom is getting things by their right names. Biodiversity studies constitute a hybrid discipline that took solid form during the s. They can be defined a bit formally, I admit, but bear with me as follows: the systematic examination of the full array of organisms and the origin of this diversity, together with the technology by which diversity can be maintained and utilized for the benefit of humanity.
Thus biodiversity studies are both scientific in nature, a branch of pure evolutionary biology, and applied studies, a branch of biotechnology.
Two events during the past quarter-century brought biodiversity to center stage and encouraged the deliberately hybrid form of its analysis.
At least one-quarter of the species on earth are likely to vanish due to the cutting and burning of tropical rainforests alone if the current rate of destruction continues. The second reason for the new prominence of biodiversity studies is the recognition that extinction can be slowed and eventually halted without significant cost to humanity.
Extinction is not a price we are compelled to pay for economic progress. Quite the contrary: As the examples of the rosy periwinkle and medicinal leech suggest, conservation can promote human welfare.
Ultimately conservation might even be necessary for continued progress in many realms of endeavor. The connection between the biodiversity crisis and economic development has been an important element in the reawakening of environmentalism in , which reached a peak when Earth Day II was celebrated on April 22—20 years after the original event. The new environmentalism continues to endure.
The industrialized countries could now, it seemed, turn more of their energies to domestic reform, including improvement of the environment. It appeared to many scientists, the public and political leaders that this opportunity was realized not a moment too soon.
What were previously viewed as mostly local events such as pollution of a harbor here or landfilling of a marsh there, had coalesced into secular global trends. Through advances in technology, scientists were able to make precise measurements of changes in the atmosphere and of the rates of deforestation and other forms of habitat destruction. And when the iron curtain lifted, the environment was revealed to be even worse off in socialist countries than in the capitalist West.
Action to reverse the decline was demanded everywhere. The Karner blue larvae are dependent on a single host plant—the blue lupine. Lupine requires a complex mix of fire, low graze pressure from herbivores, and disturbance. The butterflies have equally complex needs for winter snow cover, nectar sources, ant symbionts and traffic-free areas. In preserves, deer and rabbit populations are protected from exploitation, enabling them to build large populations.
The resulting increased browsing puts unnatural pressure on selected plants, particularly the lupine, thus reducing host availability. The Karner blue butterflies disperse across the landscape, taking advantage of unexploited habitat. They may stay in an area for 20 years, then disappear as the area becomes more overgrown and shaded. Managing the habitat is important for the future of this species. Currently, unused suitable habitat necessary for establishing new populations is being destroyed.
The delicate balance between the butterfly and habitat has been exemplified by its extirpation from four states. The Karner blue is found in Albany, Schenectady and Warren counties. Originally, the Albany pine barrens comprised 25, acres. Now there are less than 2, acres of undeveloped land. Loss of pine barrens habitat through development has resulted in a corresponding decline in butterfly abundance.
Figure 1 is an example of a site that has experienced a severe decline with the population apparently being extirpated. However, at most other sites in the Albany pine barrens, the decline has not been as severe as in this example. B i o l o g i c a l 10 D i v e r s i t y 12 Species Number of Butterflies Observed 10 8 6 4 2 0 Survey Year F i g u r e 1.
Data were collected by observing and counting adult butterflies at one site in the Albany pine barrens. This visual survey method gives researchers a relative population index number, which, although it is not the actual population size, is very useful for monitoring some organisms such as butterflies.
Each bar on the graph represents the total number of butterflies counted on different days. There were no butterflies observed on surveys in and I would like to summarize the whole picture by classifying global trends into four categories: 1. Ozone depletion in the stratosphere, allowing increased penetration of ultraviolet radiation to reach ground level. Global warming due to the greenhouse effect, in which increased levels of carbon dioxide, methane and a few other gases trap growing quantities of heat.
Toxic pollution, including acid rain. Mass extinction of species by destruction of habitats, especially tropical rainforests. The first three trends are dangerous to health and the economy—but they can be reversed. It is a matter of converting to cleaner forms of energy, changing our patterns of production and consumption, and above all, reversing population growth with an aim toward reaching supportable levels country by country.
However, extinction cannot be reversed. No species can be called back. The world is at or close to its highest level of biodiversity in the history of life, spanning 3. For almost 3 billion years, life was limited to the oceans and consisted of bacteria, blue-green algae, and other relatively simple one-celled forms. Then complex cells evolved, incorporating organelles such as nuclear membranes, chloroplasts, and cilia.
Soon afterward, these cells evolved into still more complex multicellular animals and plants. About million years ago, the concentration of oxygen in the atmosphere climbed rather quickly by geological standards to near its current level, destroying most of the anaerobic life in the oceans and on land surfaces.
A shield of ozone accumulated in the stratosphere, protecting life from harmful ultraviolet irradiation. For the first time, substantial numbers of larger animals filled the seas, and the global variety of life climbed sharply. Plants invaded the land, then animals, represented first by small arthropods and other invertebrates, then jawless fishes. The diversity of life continued to rise. Biodiversity stalled on a plateau during most of the Mesozoic Era, then climbed gradually to its current high level.
A second major principle of biodiversity is that smaller organisms are generally more diverse than larger ones. The reason appears to be simply that they fit into smaller spaces, consume less food individually, complete their life cycles more quickly, and hence are able to divide the habitats in which they live into smaller and more numerous niches.
And the more numerous the niches, the more species that can be packed into the same location. Take a typical epiphyte-laden tree in the rainforest of Peru. It may be the home of several hundred species of beetles, 40 species of ants, and as many as 50 species of orchids and other epiphytes. But it can only be the partial home for a flock of parrots, which must range over portions of the forest that contain many thousands of such trees in order to obtain enough food for survival.
Among smaller animals, insects dominate diversity. About , of the 1 million animal species described to date are insects, and some estimates have placed the actual number as high as 80 million. The reason for this amazing disproportion is uncertain. It seems likely due to the metamorphosis experienced by the majority of kinds of insects during the individual life cycle: egg to larva to pupa to adult, with the egg and pupa as passive transitional stages and the larva and adult as the active stage.
Larvae and adults are radically different in appearance recall the caterpillar and butterfly , typically feed on different foods, and even live in different sites. Another reason for the megadiversity of insects may be pre-emption. Insects were among the first small animals to adapt well to the land environment in early Paleozoic times, some million years ago, and this advantage allowed them to expand their populations and species to an extreme degree while holding their own against rival groups among the land invaders.
The pre-emption hypothesis gains some support from the fact that oribatid mites invaded the land about the same time, and today they too are exceptionally diverse and abundant. If insects and other small invertebrate animals are so much more diverse than vertebrates and larger invertebrates due to size alone, is it true by extension of the same principle that still smaller creatures such as roundworms, fungi, and bacteria are even more diverse?
The conventional answer is that for some unknown reason, they are not. But the conventional answer may prove to be wrong. The truth is that we know very little about the smallest of organisms. Because of their microscopic size and the difficulty of collecting and preserving them, they tend to be collected less frequently. Furthermore, many of the species can be distinguished only by B i o l o g i c a l 18 D i v e r s i t y sophisticated microscopic and biochemical techniques.
Take the roundworms, for example. Vast numbers occur throughout the world, with untold varieties of species living free in the soil or in the bodies of insects and other animals. Since roundworms can specialize in particular species of hosts, which are excessively diverse themselves, or even certain parts of the bodies of their hosts, they have the potential for spectacular diversification.
We simply have no idea how many kinds of roundworms live on earth. The same is true for fungi and bacteria. The number of recognized bacterial species is about 4,, but most specialists on the subject agree that this is only a tiny fraction of the real number. Bacterial species usually exist in numbers too low to detect by direct inspection, and become apparent only when given the right nutrients, temperature, and chemical environment to create obvious population blooms.
Many also flourish in very odd places, such as thermal springs or the intestines of termites. In the late s, deep drilling in South Carolina uncovered an entire new flora of bacteria living 1, feet or more below the soil surface on nutrients carried to them by water seepage. The terra incognita of the smallest organisms is the reason why students of biodiversity, in giddier moments, are sometimes willing to entertain the idea of million or more species of organisms on earth.
Yet another peculiarity of global biodiversity is its inordinate concentration in tropical rainforests. This habitat, or biome-type as it is called by ecologists, is defined as a forest growing in tropical areas with 80 inches or more of annual rainfall, allowing the growth of broad-leaved evergreen trees that form several layers of dense canopies.
The diversity of rainforest organisms is legendary, the common stuff of gossip among field biologists. For example, as many as species of trees have been identified in a single hectare 2. Each tree harbors as many as a thousand species of insects. One tree that I analyzed yielded 43 kinds of ants, approximately the same number found in the entire British Isles.
The reason for the concentration of terrestrial diversity in rainforests and their marine equivalent in the coral reefs is one of the great unknowns of ecology. The concentration is actually the result of a more or less continuous increase in diversity encountered while traveling from the poles to the equator, the so-called latitudinal gradient of biodiversity. I am going to take a deep breath and try to impart the most likely explanation from a synthesis of these hypotheses, with due respect to current evidence: B i o l o g i c a l 20 D i v e r s i t y The tropical zones generally have a more congenial climate for life, providing it with longer growing seasons, an even distribution of solar energy, and freedom from freezing and other extreme, unpredictable, shortterm changes in temperature.
The rainforest, moreover, offers a humidity regime and tree structure that is, prevalence of broad, nearly horizontal branches favorable to epiphytes such as orchids and bromeliads. The delicate life cycles of the epiphytes and their co-evolved animal populations are pre-eminently tropical. It is unlikely that the organisms could endure the freezes of the Temperate Zone. The stability of the climate and the layering of vegetation allows division of the ecosystem into large numbers of niches and a corresponding number of plant and animal species, many bound together by intricate and finely tuned symbioses.
A small shift from one part of a tree to another, or from one species of tree to another, or from one elevation on a mountainside to another, opens an opportunity for the evolution of yet another kind of animal or plant. The entirety of evolution has built the equivalent of a house of cards: vast numbers of species propped and leaning on one another and dependent on a steady environment to avoid collapse.
It used to be thought that diversity created stability; in other words, the more species were locked together by co-evolution, the less likely any one of them could be extirpated. This diversity-stability hypothesis has gradually given way to its exact reverse, the stability-diversity hypothesis, wherein external, climatic stability is thought to allow the buildup of biodiversity.
In the Temperate Zones, plant and animal species must adapt to a more drastically and unpredictably shifting environment. As a consequence, each Temperate Zone species is, on the average, likely to occur in a greater range of habitats, elevation and so forth than individual tropical species. In short, Temperate Zone species occupy a broader niche.
Fewer species can be fitted together, resulting in lower biodiversity in temperate climates. B i o l o g i c a l 22 D i v e r s i t y average as well as greater ecological flexibility. In rainforests and other tropical environments with their legions of finely adapted species, degradation of this kind has deepened into catastrophe.
The current area, then, is roughly equal to that of the United States. The forest is being cut and burned at the rate of , square kilometers a year, roughly the area of South Carolina—or, to use a more vivid measure, an area equal to a football field every second. B i o l o g i c a l 24 D i v e r s i t y early extinction within the next 30 years if current rates of habitat destruction continue unabated.
Many kinds of plants and animals simply could not spread fast enough to keep up. The Englemann Spruce, for example, has an estimated natural dispersal capacity of from 1 kilometer to 20 kilometers per century, so that massive new plantings would be required to sustain the size of the geographical range it currently occupies. Some kinds of plants and less mobile animals occupying narrow ranges might become extinct altogether. Entire arctic ecosystems might be endangered, because the warming will be greatest nearest the poles, and the organisms composing the ecosystems have no northward escape route to follow.
People often ask, why should man-induced changes be thought apocalyptic or even very serious? After all, environmental change is perpetual, and organisms have always adjusted to it in past geological times. Certainly over millions of years species adapted to alternative climatic warming and cooling, the expansion or shrinkage of continental shelves and the invasion of new competitors and parasites.
Those that could not change became extinct, but at such a relatively slow rate that other better-adapted species evolved to replace them. In the midst of endless turnover, the balance of life was sustained. But now the velocity of change is too great for life to handle, and the equilibrium has been shattered. It has reached precipitous levels within a single human life span, merely a tick in geological time.
Humanity is creating a radical new environment too quickly to allow the species to adjust. Species need thousands or millions of years to assemble complex genetic adaptations see Appendix IV, Geologic Time Table. Most of life is consequently at risk. We are at risk. There have been five previous episodes of mass extinction during the past million years, the time in which large, complex organisms flourished in the seas and on the land.
These occurred at intervals of 20 million to million years, during brief periods when the equilibrium between species formation and species extinction was upset. The most recent occurred at the end of the Mesozoic Era, the Age of Dinosaurs, 65 million years ago. Scientists generally agree that some major physical event was responsible, most likely a giant meteorite strike or abnormally heavy volcanic activity.
Life required more than 5 million years to restore its original diversity by additional evolution. We are now in the midst of a comparable extinction spasm, almost entirely by our own actions. For the first time ever, plant species are dying in large numbers. Much of future biology, I predict, will focus on biodiversity studies, carried down to the level of species and genetic strains.
The study of biodiversity comprises several levels, each of which must be understood to protect and make full use of species and genetic strains. These levels correspond roughly to the conceptual levels of biological organization employed in basic research, which are used to illuminate pattern and process all the way from DNA replication to energy flow in ecosystems.
The disciplines attending the levels are hierarchical. Starting with systematics, each feeds vital information to those up the line. In turn, the most comprehensive among them, community ecology and ecosystems studies, offer the broad vistas that guide biodiversity studies as a whole. Studying such changes as population size, species composition and distribution of organisms requires baseline data to which new information can be compared.
Biological systems are dynamic; organisms living in a specific geographic area, often called a community, respond to physical, chemical and biological factors.
As these factors change on a daily, seasonal, annual or long-term basis, the organisms in the community also change. To understand the effects of changes on these organisms, the biologist must first understand the various components that affect the community. Too often, the baseline data needed for this comparison are nonexistent because no early survey of the biological resources was conducted.
New York has taken a lead in inventorying its natural resources with the establishment of the State Geological and Natural History Survey in Modern field surveys, documented by careful notes and voucher specimens, can be used to protect rare or unusual species, to define and map their habitats and to meet government regulations for building or other permits. Because both the environment and communities are dynamic, repeated surveys or long-term monitoring of specific sites provides the greatest amount of information and allows the researcher to observe and predict the response of the community to potential environmental changes.
For example, biologists examine change in fish communities by comparing current information on fish abundance and distribution to information collected during past surveys. The simple comparison, as shown in Figure 2 describing fish communities in the Wallkill River, indicates that the composition and relative abundance of the fish community has changed markedly in this stream in the six decades between surveys. The chart shows that there were 22 species of fish B i o l o g i c a l 28 D i v e r s i t y mportant collected in the stream in and only 16 species in Factors contributing to the loss of species and change of community composition are unknown.
Had the stream been surveyed regularly, these mechanisms would be more obvious to the modern researcher, and they would be better able to understand the changes and to predict the effects of change. Community composition of fishes in the riverine section of the lower Wallkill River, New York. The comparison is based on fishes collected at four sites during and between Dashville and Montgomery. The sites were selected to match, as closely as possible, the habitats sampled in This chart shows the decline in the relative abundance and diversity of fish that has occurred in the Wallkill River.
Systematics creates two key products, monographs and inventories. Monographs are complete classifications of particular groups of organisms for some larger part of the world, such as the ferns of tropical America or the Danaid butterflies of the world. The ideal monograph describes the species in the group, presents the available information on their distribution and natural history and interprets their evolutionary history.
When appropriate monographs are available, inventories can be conducted of particular sites, including the hot spots of greatest interest in conservation.
The urgency in the need for systematics research comes from the fact that few appropriate monographs actually exist, forestalling inventories of any but a small number of relatively well-known groups such as flowering plants and birds and other vertebrates. As I noted earlier, the vast majority of species of invertebrates, fungi and microorganisms have not even been discovered, let alone described.
There is a great need to promote monographic work on selected groups that are so different from flowering plants and vertebrates in their biology as to occupy unique places in the ecosystem and require special techniques in conservation. For adventurous scientists, these other groups await exploration in the field in the same way that elephants, gorillas and rhododendrons awaited exploration in the last century. Organismic biology moves us one level of organization down from systematics, rather than up.
It comprises the physiology, genetics and life cycle studies of individual organisms. Once species have been distinguished taxonomically, those of most importance can be determined on the basis of whether they are keystone species, or close to extinction, or of potential economic importance, or offer extraordinary new biological phenomena for scrutiny.
Detailed analysis can assess their status and role in the ecosystem. The next logical link in the chain is population biology, moving us back to the level of the species. Here we study the traits of whole populations, species by species, including the detailed distribution of each selected population, its fluctuation in size through time and hence its susceptibility to local extinction, and its internal genetic diversity—also important as a factor in potential extinction. B i o l o g i c a l 32 D i v e r s i t y Community ecology addresses the manner in which species are linked in local environments.
One of the most important problems in modern biology, as well as in conservation practice, is the tightness and reach of such linkages. We know how small sets of species, such as pairs and triplets, closely interact as partners in symbiosis, competition, predation and prey. What we do not know to any extent, especially in the most species-rich, endangered communities, is the range of linkages for individual species.
How many species, for example, are keystone species whose elimination would bring down, say, or more other species? This kind of scientific research is as basic and subtle as any in molecular biology or physics. In ecosystems studies, the highest level of organization is the ecosystem, the combined biological and physical components of circumscribed domains such as islands, patches of forest and lakes.
The emphasis at this level is on the properties of energy and material flow, and for our purposes the relation of these properties to species composition. When environments are disturbed, energy and material flows are shifted, and humidity and temperature are altered.
As a consequence, some species flourish while others decline and die out. Economic analysis of local ecosystems becomes practical to the extent that knowledge of the fauna and flora increases. One very promising approach is biochemical prospecting, the screening of natural products of wild species, a relatively inexpensive procedure that can follow closely upon systematic inventories and other early biological studies.
The aim of this approach is to create new pharmaceuticals and commercial products from the wildlands and to encourage the creation of extractive reserves as an alternative to habitat destruction. The inventories should cover flowering plants and vertebrates, which are taxonomically in the best shape, and should be extended as soon as B i o l o g i c a l 33 D i v e r s i t y possible to selected groups of smaller organisms likely to display different population traits and conservation needs.
Inventories should be directed from some of the best-established field laboratory sites, such as the tropical forest stations on Barro Colorado Island, Panama, and La Selva in Costa Rica, as well as the many local stations and field laboratories throughout North America. Such studies are also best conducted at well-established field laboratory sites. Again, this kind of study is generally best conducted at well-established field laboratory sites.
Finally, given that this conceptual structure is close to the mark, the best way to promote biodiversity studies and conservation would seem to be to strengthen our experimental field stations and museums while promoting the very best studies ranging from systematics to ecosystems analyses. Our brightest young people should consider careers in biodiversity studies; our government and foundations should promote their enterprise in the service of national interest.
We already know what needs to be done and the first important steps to take. Now is the time to act. B i o l o g i c a l 34 D i v e r s i t y Biological field stations from four parts of the world: 1. B i o l o g i c a l 35 D i v e r s i t y A p p e n d i x I Glossary Acid rain Precipitation that is acidic due to the chemical reaction of nitrous oxides NOx or sulfate SO4 with water H2O , forming nitric or sulfuric acid.
These chemicals are picked up by clouds over industrial areas that burn fossil fuels. The acids formed can be carried long distances and deposited far away from their origin. Acid rain is thought to be killing some of the trees and polluting water in New York, Vermont and New Hampshire. Anatomy A branch of biology that deals with the physical structure of an organism. For example, novocaine or ether may be used during medical or dental operations, causing the patient to feel no pain.
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