Written Work by Caroline Webb

IN THE LIGHT OF PHOTOSYNTHESIS

Essay written for the John Templeton Foundation Writing Competition on the theme of
'The Power of Purpose', © Caroline Webb May 2004

At the foundation of our lives is a biological process that is responsible for all of the food that we eat and every molecule of oxygen that we breathe. It is called photosynthesis. For many of us, eating and breathing are simply two different things that we do to stay alive. We have no idea that they are intimately connected and even less of an idea about how our bodies connect with the entire evolutionary history of life on Earth. Evolution, for the human, is generally only discussed in terms of our emergence from a certain order of animals called the primates. But that is too limited a view to really gain insight into our full identity as human beings. The story is much, much bigger and billions of years longer. It goes back to the beginning of life on Earth and from there to the stars and the whole evolutionary journey of the cosmos.

The clues are to be found in that foundation of our lives: photosynthesis. In this phenomenon lies a unique pathway for discovering just how deeply connected we are to the rest of life, and to the cosmos. Within its intricate action to use sunlight to fuel the production of energy-filled molecules, there is a fuse that goes back to the beginning of everything. With the benefit of scientific research across many disciplines we can track that fuse now, and in doing so a window is opened. It reveals a staggering vista through which we may come to a new sense of our identity as human beings, and with that, a more profound sense of our purpose today. In the gleaming heart of photosynthesis lies the place where the cosmos meets micro-cosmos and purpose may be perceived as inseparable from all that exists. It is an awesome discovery. But it is not simple. It is subtle and deeply nuanced.

Photosynthesis – A Journey of Energy

Our life does not start with the breakfast, lunch or dinner we may consume today, but deep within the blindingly intense, light-shining body of hydrogen gas that sweeps across the sky every day. That’s where our muscles, our hearts, our brains get their energy—from a place that is way down deep in the Sun’s interior, where the hydrogen atoms fuse together, and become helium. By that fusion, in the cauldron of the Sun, we draw our being. As the atoms of hydrogen give way to the inescapable fate of fusing together, they release a tiny portion of their mass. The mass spontaneously converts into radiant energy, reverting to its original condition at the birth of the universe when all was too hot for atoms to exist. This hot and turbulent place, most alien to tender human beings, is where our daily life really begins.

It is actually a moment that occurred tens of thousands of years ago, for it takes a long time for the radiance to reach the Sun’s surface. But then, fleeing their birthplace, the photons of light stream out into the solar system, and in just eight minutes, a very tiny quantity of them are captured by a molecule on Earth called chlorophyll. The photons are stopped dead in their tracks by the power of this molecule’s atomic resonance. When stimulated to its state of excitement, chlorophyll is at exactly the right pitch to interact with photons of red and blue energies. In that moment too, our lives begin. In a flashing microsecond, the energy of radiance is converted into the motion of electrons in a special complex of molecules and membranes that lies waiting for just this moment inside the photosynthesizing ‘organelle’ of Earth’s plants—the chloroplast.

From now on, the energy is moving in electrochemical form. It is certainly different from the radiant photons of its previous moments but the driving power does not cease. It travels on, expressed once again in the electrically modulated world of atoms, but this time a world that is highly organized and able to use the energy to construct energy-bearing molecules to feed a microscopic body (Adenosine Triphosphate – ATP). The chloroplast then uses those molecules to grasp carbon from the atmosphere and make a store of glucose molecules from which energy is derived to power all of the other vital processes of being alive.

Eventually, a portion of that unceasingly moving energy lands on a plate on our table and we eat it. With our meal we grasp a part of the power carried forward from the birth of the universe, some 14 billion years ago, now burning as our Sun, and we make use of it ourselves. The energy goes on, carried inside a human frame. We have a life.

Earth and Life have Journeyed as One Whole

The chloroplast organelle that can perform the art of plant photosynthesis is the descendant of a humble bacterium, whose knowledge of how to do this incredible thing began back in the infancy of life itself, perhaps 3.85 billion years ago. Through that knowledge, which expresses itself as a complex sequence of actions, the planet has been utterly transformed. The history of life and the history of planet Earth, we are learning, are an entwined and interactive joint history. Earth, Sun and Life have been journeying together, as a single integral system since the earliest days of the solar system as a whole.

How did the process of photosynthesis begin? We are still in pursuit of the answers, but it is thought that the first cells originally drew energy from readily available molecules in the environment in a process called chemosynthesis. Some of the elegant skills involved in photosynthesis have their origin in this opening gambit of life’s adventure on Earth. But the readily available molecules of use in chemosynthesis eventually dried up. Life faced its first energy crisis and the bacterial cells solved it by inventing the art of photosynthesis. Through the means of certain light-sensitive ‘pigment’ molecules, they latched on to an energy supply that can last for ten billion years. This is the predicted lifetime of our Sun. Our lives have arisen out of that background, and our genetic code stretches back into those days.

Creatures larger than bacteria might never have emerged however, had not photosynthesis become refined by the species we now call cyanobacteria. A new molecular structure came into being (Photosystem II) relying on some powerful new enzymes, capable of obtaining an apparently limitless supply of hydrogen atoms—from water (H2O). The hydrogen is vital to the process. But it involves breaking the water molecule into its constituent atoms: hydrogen and oxygen. The bonds are extremely hard to break. How did this innovation arise? We cannot say. Our science of biomolecular evolution presumes that there was a chance mutation of DNA. The complexity of these enzymes, however, is challenging for this kind of explanation, as is the whole process of photosynthesis. But whether by some moment of serendipity, or by a more focused creative power embodied in the bacteria, undoubtedly ‘necessity was the mother of invention’. By at least 3.5 billion years ago, and possibly earlier, a solution to the requirement for a source of plentiful hydrogen was found.

From that moment on, the destiny of Earth and life was charged with an ever-deepening potential for novelty. Not only did the cells succeed in surviving, but they also unleashed a critically important chemical element for their own subsequent evolution. Of no use for the purpose of photosynthesis, oxygen -- the other part of the water molecule——was released into the planetary environment. Over eons, by grasping sunlight to perpetuate their own life, the cells released enough oxygen into Earth’s environment that both planet and life have been radically changed. Life and Earth have been traveling together. We share a common destiny.

The effects of the infusion of oxygen have been enormous. Through its chemical reactions with Earth’s original endowment of elements we now have an atmosphere in which 21% of the total volume is oxygen. We also have an ozone layer (03, three atoms of oxygen), very thinly dispersed but sufficient to protect life’s delicate DNA molecules from the harm that can be caused by the Sun’s ultraviolet radiation. Both these aspects of our atmosphere are in continuous replenishment today and are of vital importance for virtually all life forms. We also still have our oceans. Without the action of photosynthesis to release oxygen, which combines with hydrogen once again to form water, whatever original endowment of water on this planet would have long ago evaporated into space. Earth would be like Mars.

The steady rise of oxygen into the planetary environment did more than retain our oceans, however. It also evoked new opportunities for physiological development, each step building upon the previous one. With the aid of oxygen to harvest the energy in food molecules, life has become larger than single cells, more vigorous and much more diverse. The innovations started when certain bacteria began to thrive on the steadily growing supply of oxygen, a time thought to have occurred about 2 billion years ago. They began to practice what we call ‘respiration’—using oxygen for the final stage in the processing of energy contained in food. We now bear the descendants of one particularly successful bacterium that could respire, living as the mitochondria inside nearly all of our cells. It is in these ‘remnant’ bacteria, whose existence is seamlessly connected over billions of years of mitochondrial reproduction, that the energy in our food is finally digested, producing the energy we need to live.

In plant cells, both mitochondria and chloroplasts are to be found in great quantity. Their presence belies a planetary history in which the atoms of carbon and oxygen have been flowing from atmosphere to cell, and back again, in a steadily growing curve of change. Life began to ‘breathe’ the oxygen and consume the carbon released by respiring organisms in ever-greater exuberance. Finally, in a triumph of cellular cooperation and specialization, the first animals and plants emerged. The body of Earth began to flower.

The Power of Purpose

From the purpose of bacterial beings to stay alive, a planet full of astounding diversity and beauty has been forged. This is the amazing thing. Over billions of years, photosynthesizing organisms, and the chloroplasts that form part of plant cells, have sculpted the chemistry of the planet and with that, the creative opportunities for evolution of life. The power of that purpose, therefore, is extraordinary to contemplate. Out of an unremitting desire to live, the way has been opened for novelty to unfold. We begin to see an image of our natural history emerging that is holistic, integral and subtle. Singing an ever more interesting and complex song, the third planet from the Sun and the life that has hugged its surface, have been traveling through time on a single, entwined journey.

Viewing this background to our presence today, we are bound to see that the place of our own species is embedded within a web of life that knows no break in its history, nor any separation in its parts. Differentiation and individuation are true only up to a certain point. While each organism and species is unique and responsible for its own existence, being here at all is something that rests upon all previous stages of life, all previous chance mutations, all previous leaps of cellular imagination and community initiative. Those moments live on. In crisis or in serendipity, in abundance or in stress, life and planet Earth have always been in profound interaction. This is the integral and subtle background to our presence today that we have discovered through our scientific inquiries. And it has something to say about who we are, where we are and—crucially—where we might go. It has something to say about our purpose now, in this particular moment in human history and cosmological time.

Purpose and the Cosmos

In the last seventy years, we have discovered something of even greater importance than the heliocentric nature of our solar system, deduced nearly 500 years ago, by Nicolaus Copernicus. We have discovered that we live in an expanding universe. This primary discovery underlies all else. Out of this discovery, all other scientific learning, and all other human experiences, have been granted a cosmic context with a specific nature. It whispers to us that what we are, where we are, and how nature holds together in such extraordinary order, are all part of something that is profoundly dynamic. In motion. In process. Unfolding. As the galaxies stream forth with the billowing of space, we too, in our solar system, are moving with this greater flow of the cosmos as a whole. It places a definite stamp upon the kind of purpose we might be involved with here.

Through our observations and our theoretical work in physics, we now stand holding the unspeakably powerful notion that the universe came into being, bringing forth all the matter that would ever exist and establishing a starting point for time, around 14 billion years ago. We have traced the path of the original undivided energy at the beginning of it all. We can make out the major steps of transformation by which it has proceeded. From energy came matter (atoms of hydrogen and helium) from which galaxies of stars emerged. Some giant stars die explosively, creating all the complex atoms as they go ‘supernova’. From the enriched interstellar material, a star with planets can emerge. There may be billions of planets in the cosmos where life is present but gets no further than microbes. But if photosynthesis can get going, the chance for deeper fulfillment of cosmicpotential may arise. That potential, surely, is all to do with the construction of meaning and purpose in the universe as a whole.

In the human being, the chance for fulfillment of meaning and purpose has come to a special focus. Through us, the journey that began all those billions of years ago, can now be told, as we look back upon its unfolding. The tale of evolution has generated its own narrator. How extraordinary! Though many hours and emotions may be spent arguing amongst ourselves about how this could have come to pass, the overwhelming fact to take in is that the energy produced with the birth of the universe is the same energy at work right now—as I write, and as you read. For whatever could bring forth so much energy—enough to create countless billions of galaxies—did it, it would seem, but once. The universe is built on irreversibility. Out of this dynamic time-imbued reality, evolution itself has evolved. Purpose, as an inherent potentiality of this universe, has itself evolved. It now faces fresh evolutionary pressures.

Earth, Humanity and Purpose

We stand today—upright, curious, sensitive and intensely social beings, a few million years of hominid evolution behind us, with massive freedoms and powers of all kinds. The freedom and power we embody is one that belongs both to the planet from which we have been born, and the cosmos from which Earth has been born. From such freedom we carve our own individual destinies and a collective destiny.
What remains now for further illumination throughout global society is that our destiny as human beings is not separate from the Earth in its entirety. It never was and never will be. Despite all science fiction fantasy, and despite our forays into the solar system where outposts of humanity may one day be placed, the main action remains here, on the planet where we have been nurtured and where the spirit of purpose, over eons, has reached into new expression. And, at our hands Earth is now in trouble, its equilibrium rocked in the race to establish ‘progress’. Whereas photosynthetic action once ruled the atmosphere, we humans are now shifting the balance. We do so at our peril.

We stand, therefore, at a critical point of decision and definition of our purpose as human beings. It is a fresh moment of innovation in nature, a further step of evolution. It is also a deepening of purpose in the universe. The evolutionary advance is this: alone, amongst all other organisms, we are called upon to care about life forms other than our own. We are called to break out of the self-absorption that naturally engages all species. As at other major moments of evolution, there is a pressure mounting to take this step. Our health depends on a condition of health throughout the rest of nature. Our wealth and economic activity depend on that too. The natural order is an integral one. ‘Integral’ means everything is playing a part in the whole. Change the genetic code without caution, eliminate uncaringly this species or that, pull on one more thread— and we may find that the cloth as a whole unravels. We will discover just how embedded we are in nature, in the worst, most uncomfortable way that is conceivable.

We are called, therefore, to create a reciprocal relationship with Earth, and to become the nurturing power of life for the planet as a whole. This is the cosmic evolutionary step we are facing. If we do not heed the message about the natural order we grew out of and live within, we may find that our future will be taken away from us. There can be no dodging the realities about the way all species must live. Nothing is exempt. For a long-term future, stretching into millions or tens of millions of years more, we have to find our way into the community of life as a whole. We have to grasp this truth: we will only survive long term if we learn how to live sustainably—exactly as Nature herself does. This is a spiritual learning as well as a matter of pragmatism.

All that we need to know is already here, waiting to be listened to and seen by us, in ways that are receptive, reverent and willing to learn. Nature is our teacher and guide. We became human in the midst of all that. Our minds came to flower because we lived in deep intimacy with the vivid flowers around us, with the trees, the rivers, the land and creatures of all kinds, while above us the stars glittered and the Moon roamed. The religions of our world emerged from that primal sensitivity and they could play a vital part in rediscovering that power once again. From the religions, and evolving spiritual sensitivities of diverse kinds, a powerfully creative synthesis with our sciences can spring forth. It is already happening. This essay is one small contribution to that creative process.

The Light of Photosynthesis

Photosynthesis was invented when the first supply of energy dried up. In that moment the solar system and the universe were quickened with the power of transformation and new creativity. Today, Earth faces an equivalent moment but there is something much more tender at stake. It is the flame of meaning in the universe, brought to a special position through our presence, illuminated by the powers of our consciousness. That consciousness has its origins in the earliest days and forms of life, as increasingly revealed by our various sciences. Thus, a vision is emerging in which we may see ourselves as Earth itself, in human form. And since Earth only lives by means of the Sun, which floats serenely amidst the spiral galaxy of the Milky Way, we are also, in some most subtle way, the cosmos in human form.

As we grapple with difficult fruits of our own history, and face the challenges of creating a sustainable world, we may recall the story of photosynthesis, with its infusion of life-enhancing oxygen, and its provision day by day of every morsel of energy to live by. Our gifts have come with love, it seems to me, from the dynamic, dramatic cosmos in its mysterious, beauty-filled unfolding. Now is the time to return that love and to infuse it into our own human societies, and out into the waters, soils and atmosphere of our beloved planet. Now is the time to ignite our own powers of transformation—a new articulation of that primordial process of photosynthesis—for the sake of the sacred Life, which lives within us and in everything around us. What grander purpose can we find than this?

Acknowledgements:
Acknowledgements are due to philosophers and scientists: Brian Swimme, Thomas Berry, Teilhard de Chardin, James Lovelock and Brian Goodwin for their various intellectual contributions which the author has integrated into her own work about photosynthesis.