What is Life?:How chemistry becomes biology (3 page)

But how the initial organization associated with the simplest living system came about originally is a much tougher question. Despite the widespread view that Darwinian evolution has been able to explain the emergence of biological complexity, that is not the case. Darwinian evolution
is
able to broadly explain how a simple single-cell living organism—what one might call the microbial Adam—eventually became an elephant, a whale, or a human. But Darwinian theory does not deal with the question how that primordial living thing was able to come into being. The troublesome question still in search of an answer is:
how did a system capable of evolving come about in the first place?
Darwinian theory is a
biological
theory and therefore deals with
biological
systems, whereas the origin of life problem is a
chemical
problem, and chemical problems are best solved with chemical (and physical) theories. Attempting to explain chemical phenomena with biological concepts is methodologically problematic for reasons we will discuss subsequently, and in some sense that approach may have been partly responsible for the conceptual dead-end the subject seems to have found itself in.

Significantly, Darwin himself explicitly avoided the origin of life question, recognizing that within the existing state of knowledge the question was premature, that its resolution at that time was out of reach. So the question of how the first microscopic complexity came into being remains problematic and highly contentious. Did a cellular precursor to that exquisitely complex miniature factory that is the living cell come together purely by chance, by the various bits and pieces randomly linking up in precisely the right manner? Not very likely. To draw on an analogy popularized by Fred Hoyle, the well-known astronomer (though famously misapplied), the likelihood of such an event would be similar to that of a whirlwind
blowing through a junkyard and assembling a Boeing 747. Life’s organized complexity
is
strange, very strange. And how it came about is even stranger.

There is another facet to the organized complexity of living systems that has been strikingly evident to humankind for thousands of years—life’s purposeful character. That purposeful character is so well defined and unambiguous that biologists have come up with a special name for it—teleonomy. The ‘teleonomy’ word was introduced about half a century ago to distinguish it from the ‘teleology’ word with its cosmic implications, and we will have more to say about how these terms relate to one another in
chapters 2
and
8
. At this point let us simply note that teleonomy, as a biological phenomenon, is empirically irrefutable. The term simply gives a name to a pattern of behaviour that is unambiguous—all living things behave as if they have an agenda. Every living thing goes about its business of living—building nests, collecting food, protecting the young, and, of course, reproducing. In fact, within the biological world that’s how we broadly understand and predict what goes on. We understand a mother nurturing her offspring. We know better (or should know better) than to step between a mother bear and her cub. We understand two males competing for a female; we understand a stray cat rummaging through a trash bin. We intuitively understand the operation of the biological world, including, of course, all human activity, through life’s teleonomic character.

In the non-living world, by comparison, understanding and prediction are achieved on the basis of quite different principles. No
teleonomy there, just the established laws of physics and chemistry. You throw a ball into the air and you want to know where it will land? The precise landing point is not calculated by considering the ball’s purpose. The ball has no purpose. Only Newton’s laws of motion will provide the answer. You mix some chemical compounds together and you want to know whether they will react and what materials are likely to form? You consider and apply the appropriate chemical rules, depending on the nature of the problem, and you come up with a prediction. No purpose, no agenda—just inviolate laws of nature. The notion of purpose within the inanimate world was laid to rest with the modern scientific revolution of the seventeenth century.

The very existence of teleonomy however, leads us to a strange, even weird, reality: in some fundamental sense we are simultaneously living in
two
worlds each governed by its own set of rules—the laws of physics and chemistry within the inanimate world and the teleonomic principle that dominates the biological world. Indeed, given the existence of two distinct worlds we find ourselves interacting quite differently with each of those worlds. Consider our interactions within the inanimate world. We move from one place to another as required, we try to keep warm when it is cold, to keep dry when it rains, we build a physical enclosure to live in to protect ourselves and to facilitate life’s activities. We learn to climb up slopes despite the gravitational force, to generate fire for cooking, to manufacture tools for improved function, to plug a hole in a leaking roof, to avoid physical injury, and so on. All of our interactions with the inanimate world are based on the recognition that there are certain laws of nature, described primarily by the physical sciences, which govern the manner in which the universe functions.
Understanding those laws helps us to keep out of trouble, and, even better, enables us to take advantage of nature’s
modus operandi,
thereby allowing us to further life’s goals more effectively. In fact that is the essence of technology—creating systems that exploit nature’s laws in a beneficial manner.

Our interactions with the living world, however, are of a quite different kind and are much more complex. As we have already noted, the living world is teleonomic—all living creatures are busy furthering their agenda, and in doing so they must take into account the particular agenda of other living beings. Accordingly, living things create a web of interaction with other living things, making many of our actions mutually dependent. Consider us humans. We communicate and deal with members of our immediate family, with our work colleagues, with other members of our society in an endless series of interactions—by spoken and written word, more subtly without words, by gestures. Some of these interactions are cooperative in nature, some competitive. Ordering a cappuccino at the local café or going to the hairdresser exemplify cooperative interactions, while bargaining in the market over the price of some article or fending off an intruder are competitive interactions. Our lives involve endless interactions of both types as we individually pursue our ‘purpose’ and get on with life’s goals. We also continually interact with a wide range of non-human life forms. Our need for sustenance is satisfied by feeding on other living creatures, both animal and vegetable, and we protect ourselves against the life forms that threaten us, whether multicellular creatures—bears, sharks, snakes, mosquitoes, or spiders—or from single-celled creatures—bacteria of endless variety. Many non-human interactions are cooperative—the pet dog that we feed which provides
companionship and warns us of intruders, the billions of bacteria in our gut to which we happily provide room and board, and who return the favour by assisting us with our digestion and more.

We are so used to this dual state of affairs—matter that exists in both living and non-living forms—that much of what has been said here is glaringly obvious and very much taken for granted. Familiarity breeds acceptance, if not contempt. But if I were to tell you that on Mars all material forms obeyed one set of principles, yet on Venus they followed another different set, we would all be startled. How could that be? Two material forms broadly following two distinct sets of principles? The fact that here on Earth there exist two material forms that are distinct in character, are governed by different organizational principles, which comfortably coexist, and in fact continually undergo material interchange—non-living matter is continually transformed into living matter, and vice versa—demands some explanation. How can this stark duality in the nature of matter exist and what does it signify?

Before going any further let me be unequivocal and make one point perfectly clear: it goes without saying that within the teleonomic world the same underlying rules of physics and chemistry that govern the inanimate world are still operative. No doubt about that. When a person falls off a ladder the law of gravity is operative in exactly the same way as when a bag of sugar falls off a shelf. But in many respects those natural laws are of little or no use when applied to living systems. The law of gravity and the Second Law of Thermodynamics aren’t particularly helpful when you are arguing with a neighbour over some property issue, or when seeking to renew an expired licence, or when fending off an aggressive dog. Within the living world those same laws have little predictive
value—they are certainly operative but appear to be of only secondary importance. The underlying rules of physics and chemistry have somehow been taken hostage and overwhelmed by another more dominant set of principles. If you want to predict the actions of a crouching lion preparing to pounce on an unsuspecting zebra, a mother tending to her young, a lawyer planning to sue you on behalf of an aggrieved client, or indeed any other teleonomic action, the laws of physics and chemistry are of little use. Neither a physicist nor a chemist will be able to offer a useful prediction. If you want to make a prediction about some impending event in the living world, go ask a biologist, psychologist, economist, lawyer, or other teleonomic specialist, depending on the nature of the question.

Not surprisingly then, much of human knowledge and understanding involves the teleonomic, rather than the physicochemical world. Consider for a moment any large university with its many faculties, each dedicated to a particular field of enquiry. The faculties of humanities, commerce, and law (and to a lesser extent, the faculty of medicine), are dedicated to the teleonomic world with its many manifestations. There is just one faculty—the faculty of natural sciences—that dedicates itself specifically to the study of the natural world, and even within this faculty we find the department of biological sciences grappling awkwardly with the teleonomic reality, uncertain as to how the paradox of a dichotomic world can and should be resolved. That, then, is the undeniable, yet so far inexplicable reality—the laws of nature, as primarily articulated in the subjects of physics and chemistry, offer few insights into the predominantly teleonomic world of which we find ourselves very much a part.

Intriguingly, despite the irrefutable teleonomic character of living systems, some biologists still have difficulty in coming to terms with that extraordinary character. The troublesome ‘purpose’ word, now sanitized and repackaged into the scientifically acceptable ‘teleonomy’ word, still leaves many modern biologists squirming uncomfortably. The scientific revolution’s overthrow of 2,000 years of teleological thinking has left biologists anxious and unwilling to accept even the slightest vestige of that earlier, misplaced way of thinking. But there is no denying the teleonomic principle. The evidence supporting it is simply overwhelming, all around, literally endless, and cannot simply be dismissed out of hand.

In fact, it is intriguing to point out that those biologists who have argued against the concept of teleonomy, have, without realizing it, demonstrated their total faith in the principle by their everyday actions. Those scientists, like us all, actually stake their lives on its validity. Every time we get into a motor car, for example, we are betting our lives on teleonomy! Our purpose in getting into our car is to get to some destination, and to do so safely. On the roads we have to manoeuvre through an endless stream of vehicular metal—the other cars—careering about hither and yon, a real threat to life and limb. The consequences of a collision between any two metal hunks can be personally disastrous, yet we happily accept that risk day by day. Why? Because of teleonomy. We know that within every other metal hunk careering about, there is a driver whose purpose is identical to our own—to get to his destination in one piece! Though one occasionally comes across an erratic driver who seems to prove the exception to the teleonomic rule, for most of us, on most days, that teleonomic principle operates reliably and, as anticipated, we arrive at our destination safely. So those so-called
disbelievers in teleonomy are actually silent and committed believers. The world we have to navigate our way through on a daily basis is composed of both biological and non-biological systems. When dealing with the non-biological world we intuitively apply the laws of physics and chemistry. But, consciously or unconsciously, no person would be able to get through a single day without continuous application of the teleonomic principle. No doubt whatever, in the living world, teleonomy, as a predictive and explanatory principle, is the way to go.

The fact that multicellular animals, like us, behave in a purposeful manner may not appear that surprising. After all, as already noted, we animals are highly complex—we possess a brain and nervous system so it might be argued that in us animals the teleonomic character is just a reflection of significant neural complexity. But here’s the surprise. It is not just multicellular cognitive beings—humans, monkeys, camels, and the like, with a brain and central nervous system that manifest this teleonomic character. That character is also clearly manifest at the level of the single cell! Put a bacterium in a glucose solution in which the glucose concentration is variable and the bacterium ‘swims’ toward the high concentration region. That phenomenon is called chemotaxis. The bacterium, which utilizes the glucose’s chemical energy to power its metabolic processes, is effectively going out for dinner, much like the crouching lion about to pounce on a zebra.

Of course a bacterial cell cannot swim in the conventional sense of the word. A simple bacterium such as
E. Coli
is powered by several flagella, which, depending on the direction of flagella rotation, enable the bacterium to direct its motion within the solution. If the solution contains nutrition, then the bacterium rotates the
flagella in one direction such that its motion is toward the nutrition. However, if the solution contains toxins, then it rotates the flagella in the opposite direction causing the bacterium to tumble, thereby changing its direction away from those toxins. The directed swimming action of the bacterium is unambiguous: without a brain or in fact any neural activity whatever, that clump of chemical aggregates within a membrane (which is itself a chemical aggregate) that we call a living bacterium follows its agenda of seeking out its next meal, keeping out of trouble, and getting on with its life. The fundamental behavioural patterns of bacteria and humans are not as different as one might initially conceive.