The Lying Stones of Marrakech (55 page)

Before visiting the church several years ago, I had encountered the Latin phrase
status quo
only as a general description for leaving well enough alone. But I learned that the phrase can also be used as a proper noun—capital
S
, capital Q. In 1852, after centuries of more serious bickering, the six groups signed an agreement, called
the
Status Quo, to regulate every move and every square inch in the building. At this point, I will yield to Baedeker's
Guide to Jerusalem
(1982 edition), a publication generally known for authoritative and stodgy prose but uncharacteristically pungent in this case:

No lamp, no picture, nothing whatsoever may be moved without its giving rise to a complaint. The rules governing when and where each community may celebrate Mass are minutely prescribed as are the times when the lamps may be lit and the windows may be opened. Everything must be done in accordance with the originally agreed rules, i.e. the “status quo.” … Modifications to this are persistendy being sought and just as persistently rejected—they even cropped up in the negotiations for the Treaty of Versailles and in the League of Nations… . Anyone hoping to find harmony and quiet contemplation … is due for a disappointment—the sects are on a Cold War footing. Even the background noise can be put down to psychological warfare—the sound of the blows of hammers and chisels constantly engaged on improvement work mingles with the chanting of Greek plainsong, blasts from the Franciscan organ and the continual tinkling of Armenian bells.

And lest anyone hope that equality might reign among the six groups, I hasten to point out that the Status Quo assigned 65 percent of the church to the
Greek Orthodox, while granting the Abyssinians—the only black African group by ethnicity—-just the tomb of Joseph of Arimathea (“a tiny cavity that can only be reached by passing through Coptic territory,” to quote Baedeker's one more time). Adding insult to this injury, the poor Abyssinians can't even reside within the church but must live instead in tiny cells built on the roof! (And let me tell you, it was really hot up there the day I visited.)

To move from a ridiculous story about a sublime place to the fully ridiculous all around, I got the idea for this essay from an English newspaper story of July 9, 1997: “Punch-up Between Brewery Rivals Over Future of Historic Hostelry.” One of London's most interesting pubs, the Punch Tavern on Fleet Street, bears a name that reflects a former role as the favorite watering hole for staff members of the famous humor magazine. These ghosts of the past could have filed quite a story on the current situation. Bass, a large national brewery, owns two-thirds of the property, including the only toilets. But Samuel Smith, a smaller, regional operation, bought the other third, including the passageway for delivery of beer to the Bass side. The two businesses have coexisted in constant tension and bickering but have now opted for something closer to the Holy Sepulchre solution of strict division. A new wall now rises within the pub, and the Bass people are building “a new cellar drop so workers can move beer supplies without using Samuel Smith's passageway.” We must assume that the Smith folks will construct some new toilets, for we all know that such items rank second only to what comes in the other end as a necessary fixture in these establishments.

One last item, ridiculous but personal this time, will serve to establish this theme as a generality. My brother and I shared a small room throughout our childhood. We usually coexisted reasonably well, but we did have our battles from time to time. One day, following our worst blowup, Peter decided that we would just have to divide the room right down the middle, and each of us promise never to set so much as a toe into the other's territory. He proceeded to gather all his possessions and move them to his side. But I just lay on my bed laughing—as he got progressively angrier at my lighthearted approach to such a serious situation. When he finished all the moving and shoving, he confronted me in a fury: “What are you laughing about?” I didn't say a word, but only lifted my finger and pointed at the room's single door—located on my side. Fortunately, Peter started to laugh too; so we made up and amalgamated all our stuff again.

If people, representing a mere few billion souls within a single species spread throughout the planet, can generate so much strife about divvying a space, what
can nature possibly do with millions of species, gazillions of individuals, and nothing with the ability or power to negotiate, or even to understand, a status quo? Much of ecological theory has been devoted to debating concepts that may usually be framed differently, but really represent variants of this fundamental question.

Consider just two examples that generally make the rounds in any basic college course on evolution. In discussing the crucial question of how many species can coexist in a single habitat (obviously an ever more important issue as natural spaces shrink before human onslaught, and many species face imminent extinction), students invariably hear about something called the “competitive exclusion” principle, or the notion that two species cannot occupy the same “niche.” This conclusion follows more as a logical consequence of natural selection than an observation from nature. If two species lived in truly identical environments, sharing all the same spaces and resources, then one of the two would surely hold some advantage, however slight, over the other, and the relentless force of natural selection, acting on even the tiniest differential over countless generations, should secure total victory for the species with a small edge in the competitive struggle for existence.

But this principle probably says less than its weighty words seem to imply, for niches do not exist independently of the species that inhabit them. Niches are not comparable to houses in a suburban development, built “on spec” and fully decked out with all furnishings and utilities before people come to buy under a strict rule of “one lot for one family.” Niches are constructed by organisms as they interact with complex environments—and how could two different species read an environment in exactly the same way for all particulars?

A related principle (and second example) called “limiting similarity” attempts to put this theme into a more reasonable and testable light. If two separate species cannot be identical in appearance and behavior, and cannot read the surrounding environment in exactly the same way, then how close can they be? What are the limits to their similarity? How many species of beetles can live in a tropical tree? How many species of fishes in a temperate pond?

We can at least pose such a question without logical contradiction, and we can test certain ideas about minimal discrepancies in body size, feeding preferences, and so on. Much useful research has been done on this subject, but no general answers have emerged. And none may be possible (at least in such simplistic form as “no more similar than a 10 percent difference in body weight on average”), given the irreducible uniqueness of each species and each group of organisms. Beetle rules will almost surely not work as fish rules, not to mention the vastly more different world of rules for bacteria.

But if we cannot generate quantitative laws of nature about numbers of species in a single place, we can at least state some general principles. And the rule behind Jerusalem's Status Quo, whatever its moral dubiety in the ethical systems of
Homo sapiens
, provides a good beginning: large numbers of species can be crammed into a common territory only if each can commandeer some room of its own and not always stand in relentless competition with a maximally similar form.

Two general strategies may be cited, the second far more interesting than the first, for acquiring the requisite “breathing room”—a little bit of unique space that no other species contests in exactly the same way. In the first strategy—the “Holy Sepulchre solution” if you will—two species perceive the surrounding environment in basically the same manner and therefore must divide the territory to keep out of each other's way. Division may be strictly spatial, as in my fraternal dispute about our single common room. But organisms may also use nature's other prime dimension and construct temporal separations as well. The Status Quo divides the space within the Church of the Holy Sepulchre, but the agreement also decrees when the unitary domain of sound belongs to the masses, instruments, and voices of various competing groups.

To make an ugly analogy, based on cruel social practices now thankfully abandoned, but in force not long ago, I encountered both spatial and temporal modes of segregation when I began my college studies in southwestern Ohio during the late 1950s. The town movie theater placed whites in the orchestra and blacks in the balcony, while the local skating rinks and bowling alleys maintained different “white” and “Negro” nights. (Student and community activism, spurred by the nascent civil rights movement, fought and vanquished these cruelties during my watch. I remember my own wholehearted and, in retrospect, pretty inconsequential participation with pride.)

An instructive evolutionary example of this first strategy arises from a classical argument about modes of speciation, or the origin of a new species by branching from an ancestral population. Such branching may occur if a group of organisms can become isolated from the parental population and begin to breed only among themselves in a different environment that might favor the evolution of new features by natural selection. (If members of the separating group continue to interact and breed with individuals of the parental population, then favorable new features will be lost by dilution and diffusion, and the two groups will probably reamalgamate, thus precluding the origin of a new species by branching.)

The conventional theory for speciation—called allopatric, and meaning “living in another place”—holds that a population can gain the potential to
form a new species only by becoming geographically isolated from the ancestral group, for only strict spatial separation can guarantee the necessary cutoff from contact with members of the parental population. Much research into the process of speciation has focused on the modes of attaining such geographic isolation—new islands rising in the sea, continents splitting, rivers changing their courses, and so on.

A contrasting idea—called sympatric speciation, or “living in the same place”—holds that new groups may speciate while continuing to inhabit the same geographic domain as the parental population. The defense of sympatric speciation faces a classic conundrum, and most research on the subject has been dedicated to finding solutions: if isolation from members of the parental population is so crucial to the formation of a new species, how can a new species arise within the geographic range of the parents?

This old issue in evolutionary theory remains far from resolution, but we should note, in the context of this essay, that proposed mechanisms usually follow the Holy Sepulchre principle of granting the new group a room of its own within the spatial boundaries of the parental realm—and that such “internal isolation” may be achieved by either the spatial or the temporal route. The best-documented cases of the spatial strategy invoke a process with the technical name of
host specificity
, or the restriction of a population to a highly specific site within a general area. For example, to cite an actual (although still controversial) case, flies of the genus
Rhagoletis
tend to inhabit only one species of tree as an exclusive site for breeding and feeding. Suppose that some individuals within a species that lives on apple trees experience a mutation that leads them to favor hawthorns. A new population, tied exclusively to hawthorns, may soon arise and may evolve into a separate species. The hawthorn flies live within the same geographic region as the apple flies, but members of the two groups never interbreed because each recognizes only a portion of the total area as a permissible home—just as the six sects of the Holy Sepulchre never transgress into one another's territory.

The same principle may work temporally as well. Suppose that two closely related species of frogs live and reproduce in and around the same pond, but one species uses the day-lengthening cues of spring to initiate breeding, while the other waits for the day-shortening signals of fall. The two populations share the same space and may even (metaphorically) wave and wink at each other throughout the year, but they can never interbreed and can therefore remain separate as species.

In the second, and philosophically far more interesting, strategy for securing a requisite room of one's own, species may share the same region but avoid
the need for a natural equivalent of the Status Quo, because they do not perceive each other at all and therefore cannot interfere or compete—blessedly benign ignorance rather than artfully negotiated separation. This fascinating form of imperception, which can also be achieved by either spatial or temporal routes, raises one of the most illuminating issues of intellectual life and nature's construction: the theme of scaling, or strikingly different ways of viewing the world from disparate vantage points of an observer's size or life span, with no single way either universally “normal” or “better” than any other.

To begin with a personal story, I share my Harvard office with about a hundred thousand trilobites, all fossils at least 250 million years old, and now housed in cabinets lining the perimeter of my space. For the most part, we coexist in perfect harmony. They care little for my eye-blink of a forty-year career, and I view them with love and respect to be sure, but also as impassive, immobile pieces of rock. They cause me no trouble because I just move the appropriate drawers to an adjacent room when a visiting paleontologist needs to study a genus or two. But one week, about ten years ago, two British visitors wanted to look at
all
Ordovician trilobites, an endeavor that required exploratory access to all drawers. I had no choice but to abandon my office for several days—a situation made worse by the stereotypical politeness of my visitors, as they apologized almost hourly: “Oh, I do hope we're not disturbing you too much.” I wanted to reply: “You bloody well are, but there's nothing I can do about it,” but I just shut up instead. I relaxed when I finally figured out the larger context. My visitors, of course, had been purposely sent by the trilobites to teach me the following lesson of scaling: we will let you borrow this office for a millimoment of our existence; this situation troubles us not at all, but we do need to remind you about the room's true ownership once every decade or so, just to keep you honest.