Biological Diversity:
THEOLDESTHUMANHERITAGE
By
Edward O. 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. Here are the names of several: New England boneset, Furbish’s lousewort,
threadleaf sundew, fairy wand and hairy beardtongue. 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. But one of them, the rosy periwinkle (Catharanthus roseus), is the source of alkaloid chemicals vinblastine
and vincristine, used to cure two of the most deadly forms of cancer: Hodgkin’s disease, especially dangerous to young adults, and acute
lymphocytic leukemia, which, before the periwinkle alkaloids, was a virtual death sentence for young children. These anti-cancer
substances are now the basis of an industry earning more than 100 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.
On a global scale, one out of ten plant species has been found to contain anti-cancer substances of some degree of potency. 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? Wrong. 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. Medicinal leeches are now the basis of a $4 million annual
business. 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 1.4 million. By “known to science” we mean characterized anatomically and given a
scientific name, such as Canis familiaris for the domestic dog, Hirudo medicinalis for the European medicinal leech, and Homo sapiens
for humans. 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. The truth is that we don’t
know even to the nearest order of magnitude the amount of diversity. In other words, we cannot say whether the figure is closer to 1
million, 10 million or 100 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. Some groups of organisms, such as fungi and mites (small spiderlike 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. In the Chocó region of Colombia, as many as
half the plant species, including trees and shrubs, still lack a scientific name.
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. So is ecology, the extremely important discipline that explores the relationships of organisms
to their environment and to one another. A great deal of the future of biology depends on the strengthening of taxonomy, for if you can’t
tell one kind of plant or animal from another, you are in trouble. Some kinds of research may be held up indefinitely. As the Chinese say,
the beginning of wisdom is getting things by their right names.
The study of classification and expertise on “obscure” groups of organisms such as periwinkles, leeches, springtails and mites
may receive the needed boost by association with what has come to be known as biodiversity studies. Biodiversity studies constitute a
hybrid discipline that took solid form during the 1980s. 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. The first was the
recognition that human activity threatens the extinction of not only a few “star” species such as giant pandas and California condors, but
also a large fraction of all the species of plants and animals on earth. 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 1990, 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. It arose with auspicious timing at the end of the Cold War, as Eastern Europe abandoned communism and Russian-U.S. relations
entered their most cooperative period since the Second World War. 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.
It is possible that the next hundred years will become known as the “Century of the Environment.” If in the fullness of time that
prophecy comes true, the beginning of this era might be marked by historians by environmental disasters, such as the 11 million-gallon
Exxon Valdez oil spill off the coast of Alaska, the 350 tons of depleted uranium weapons still lying on Persian Gulf War battlefields, and
the continued exploitation of precious ecosystems like the Brazilian Amazon, where deforestation, mining and over-development
continue to flourish.
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.
2. 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.
3. Toxic pollution, including acid rain.
4. 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. Extinction of
species, or the reduction of biodiversity, is the one process that is being perpetrated not only on our children and grandchildren but also
on our descendants 10,000 years from now and beyond—as far into the future as can be imagined.
With that somber but essential theme as background, let me now review some of the key facts about global biodiversity. The
world is at or close to its highest level of iodiversity in the history of life, spanning 3.75 billion years. This buildup has been associated
with changes in the atmosphere, the most important of which were caused by organisms and their innovations as they adapted to the
changing atmosphere and other parts of the environment. 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 600 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. It is a supreme irony that mankind, the great destroyer of life, began as one of the products of the living
world’s maximum proliferation.
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 750,000 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. As a result, still more niches are generated by the
combinations of life cycles. 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 400 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
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 d iversification. 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 4,000, 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 1980s, deep drilling in South Carolina uncovered an
entire new flora of bacteria living 1,000 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 100 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. Tropical rainforests today cover only about 6% of the land surface (9 million square kilometers),
but they are generally thought to contain more than half the species of organisms on earth. The diversity of rainforest organisms is
legendary, the common stuff of gossip among field biologists. For example, as many as 300 species of trees have been identified in a
single hectare (2.5 acres) in the Peruvian Amazon; this compares with 700 native species found in all of North America. 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 theirmarine 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. When biologists say “unknown” in this particular case, they really mean “not known with certainty.” Several
hypotheses have been advanced, any one of which—or all of which—could be true to some extent. 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: 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, short-term 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.
This “elevated swampland” with its little pools of water and moist root masses offers vast numbers of additional living sites for animals.
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 diversitystability 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. Destructive human activity,
including habitat removal, pollution, and excessive
exploitation, have reduced large numbers of plant and animal species in the Temperate
Zones even though they are “tougher” in the sense of having wider ranges on the 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. Rainforests occupy about 9 million square kilometers currently, down some 45% from the original cover before the coming
of man. The current area, then, is roughly equal to that of the United States. The forest is being cut and burned at the rate of 100,000
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. Employing simple models based on the known relation of the area of islands and habitat patches to the number of species that
can coexist, I have conservatively estimated that on a worldwide basis the ultimate loss attributable to rainforest clearing alone is from
0.2% to 0.3% of all species in the forests per year. Taking a very conservative figure of 2 million species confined to the forests, the
global loss that results from deforestation is thus at least 4,000 to 6,000 species a year. That, in turn, is on the order of 10,000 times
greater than the naturally occurring background
extinction rate that prevailed before the appearance of human beings.
Although 4,000 species a year extinguished or doomed is a shocking figure, it is still almost certainly a gross underestimate.
When we consider that the true number of plant and animal species limited to the rainforests may well be in the tens of millions, and that
many, or even most, species in these areas are very limited in distribution, even small reductions in forest coverage can make them
vulnerable to extinction. Add to this the species extinctions occurring in other habitats worldwide, and the animal extinction rate could
easily be 10 times higher—that is, 2% or more of all rainforest species, 50,000 or more species worldwide. A common estimate among
biodiversity specialists, one to which I subscribe, is that one-fourth of the species of organisms on earth are likely to be eliminated
outright or doomed to early extinction within the next 30 years if current rates of habitat destruction continue unabated.
Habitat destruction is far from the whole picture. It represents most of the problem in warm climates, but global climatic
warming due to the greenhouse effect is a potentially major second force in cold temperate and Polar Regions. A poleward shift of
climate at the rate of 100 kilometers or more per century, which is considered at least a possibility, would leave wildlife reserves and
entire species ranges behind. 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. Isn’t the human impact just one more form of
environmental change? 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 IVGeologic 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 500 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 140 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. If a remedy is not
found, we could continue on to approach the greatest crisis of all, the Permian crash of 240 million years ago, when 77% to 96% of all
marine animal species perished. As the paleontologist David Raup put it, at that time “global biology (for higher organisms, at least) had
an extremely close call.” There is an additional, sinister note in the current extinction spasm. For the first time ever, plant species are
dying in large numbers. The world’s flora survived the end of the Mesozoic Era more or less intact, but now it is being eroded swiftly—
with eventual consequences impossible to predict.
Let me now shift gears abruptly, by saying that catastrophe can be replaced by
a bright future if the world’s fauna and flora are saved and put to use for the benefit of humanity. This new enterprise, which should
command our attention as fully as biomedical science and space exploration, will require the revitalization of “classical biology” and the
unification of the best efforts of scientists, political leaders and business entrepreneurs. 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.
Systematics, or taxonomy, is at the base of biodiversity studies for the simple reason that if species cannot be identified they
cannot be studied or marked for preservation. 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. Typical inventories might include lists of the
ferns, butterflies, or ideally all the species found in a rainforest on Cape York or the Chocó region of Colombia. 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
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, 100 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.
In conclusion, here is the way these several fields of study can be fit together in the service of conservation and use of biodiversity:
• Promote monographic studies of the poorest known groups, especially those
likely to display novel population traits and conservation needs.
• Encourage inventories of “warm areas,” i.e., species-rich areas under considerable
environmental assault, to identify the true hot spots within them that
are both species-rich and most threatened, with an aim toward early remedial
action. The inventories should cover flowering plants and vertebrates, which
are taxonomically in the best shape, and should be extended as soon as
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.
• Focus on selected groups of species for those physiological and genetic studies
most likely to identify the causes of population decline and extinction. Such
studies are also best conducted at well-established field laboratory sites.
• Select groups of organisms for studies of species linkages, the most basic level
of community organization, aimed at disclosing the reach of such linkages
and the nature of keystone species. Again, this kind of study is generally best
conducted at well-established field laboratory sites.
• Promote studies of ecosystem changes in natural habitats under assault, as
these changes affect community cohesion and threaten the safety of keystone
species.
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.
Discussion Questions
1. What is biodiversity?
2. Why is biodiversity important?
3. What recent worldwide events have made the importance of biodiversity and
the health of the environment more widely recognized?
4. Is there more or less diversity now than 100 million years ago?
5. How long ago did the diversity start to increase? Why?
6. Is there more or less diversity among small organisms? Why?
7. How much do scientists know about all the plants and animals on earth?
8. What is the science of systematics? Taxonomy? Classification?
9. Is an ecologist the same as a taxonomist? How are they the same or different?
Do they work together?
10. Why is it important to know the name of an organism?
11. Do scientists have a name for every plant and animal on earth?
12. How many plants and animals are there on earth? What are scientists’ best
guesses?
13. Can you name five plants that are used medicinally?
14. What can a leech do for humans?
15. Why are insects useful? Give two examples.
16. What areas of the world are called tropical?
17. What is unique about the way plants grow in the tropics?
18. Why are the tropics particularly rich but fragile environments?
19. Where is Madagascar?
20. Why do so many of the plants and animals live in the tropical rainforest?
Why do many of them live in the canopy of the forest?
21. What is extinction?
22. Can extinction be reversed?
23. When did much of the current environmental destruction and change start
to occur?
24. Have there been other times in history of the earth when mass extinction
occurred? When? Why?
25. What possible conditions caused the disappearance of the dinosaurs?
26. What is the major difference between environmental changes now and
environmental changes 300 years ago?
27. What is the greenhouse effect?
28. What are the major causes of rainforest destruction?
29. Do you see signs of environmental destruction in your home area?
What are they?
30. Do you know of a wildlife preserve near your home?
31. Do you know of a biological research station or institution in your area?
Have you been to visit it? Is there a scientist on its staff? What does he or
she study?
32. Can you list five areas in which biological scientists specialize?
33. Are there plants and animals threatened with extinction in the northeastern
United States? Can you name some of them?
34. Name some animals that are not threatened with extinction in New York.
Why are they not considered threatened or endangered?
35. Can you name two environmental groups dedicated to saving biodiversity?
36. What are some things we each can do to help preserve biodiversity?