LIVING things extract energy from their environment and use it to modify their surroundings in order to make their preservation possible.

The never ending story of the birth and growth of life on planet Earth has bedevilled the human mind and psyche for as long as the man has existed. Perhaps 12,000 years, or perhaps 40,000 years or more years of the modern humans’ existence, depending on which period you would consider as suitable for your reckoning — whether at the height of the Ice Age when man roamed the steppes, or the period after the end of the last Ice Age (till today) when humanity actually flourished.

That also answers the question: How long has the man existed? Was man in the same neat form ever since he came to exist, or his shape, form and profile went through gradual, almost imperceptible change with the passage of time? We shall have to wait a while to answer that tricky question, but right now we must consider the birth of life itself.

Before coming to fruition, life went through pangs of development that took up a couple of billion years before it branched out in various directions some 200 million years or so ago. It started out quite humbly, and sedately, and remained so for over a billion years, that is, half the total period till now. The process of development, growth and proliferation was equal for animals, trees, fishes, even mountain ranges, which came and went like any life form, thanks to plate tectonics. Despite the imposing presence of mountains covering a large part of land as well as the seas; their seemingly unchanging profiles still go through the pangs of growth, break ups and change perennially, albeit slowly.

In the recent past we considered at length the painstaking movement of land masses (fancifully named as plate tectonics), carrying on their weary bulk, all those mountain ranges, forests, lakes and river systems, besides billions of animals. But we have yet to consider in some detail the growth and proliferation (that is, spread in all directions) of life from the humblest stage to the more sophisticated form recognisable in these times. From viruses to bacteria to amoeba to fully developed life, in a process that took some two billion years of grinding, gut-wrenching effort.

We already know from observation that remnants of seas, and the life that flourished there have been found on, or near the present-day distant mountain tops where one would expect to find them in the least. This includes shells, fish fossils and a wide variety of the remains of aquatic life since petrified, and reduced to fossilised form.

This evidently means that the distant parts of the earth, that is, most unlikely of places, were once teeming with aquatic life. And that these mountain tops were once seas. Otherwise such a variety would be hard to find on rugged mountain tops of all the places. The sea life would be where the sea is!

The same place now has a mountainous range in its place, having nevertheless left a remarkable fingerprint from millions of years in the past when the fish and the seashell are purported to have lived over the present-day hilltops!

Back to the origin of life!

In order to consider the exhaustive story of life, we must first settle on the three basics involving life and its complexities.

Firstly, what we really mean by life. A living thing is not only a physical object but a whole process. It has the uncanny ability to duplicate and protect itself. Therefore, (and it is important to note that) life is based on information that contains the directions for the processes aimed at duplication and preservation.

Secondly, to study the origin of life; life on earth began with the simplest chemical reactions that happened naturally in a million places at the same time, in the beginning. It is another matter that similar reactions spawned life on other worlds elsewhere in our galaxy, the Milky Way, or beyond, in other galaxies (if at all they did). We shall probably never know the answer, but make do with educated speculations alone.

Thirdly, the study of the inexorable evolutionary processes; the survival of the stable species, among a vast variety of species, transformed the simple organism that lived in the earth’s oceans and shallow waters into a wide variety of creatures with special adaptations.

All of them are equipped with protection and adaptation gears (consider again, the rose’s thorns). Evolution is so natural a process, but clumsy and time consuming. The life process is aimed at survival, from hunger, from predators and even from environment all of which may not be benign for all species. Living things extract energy from their environment and use it to modify their surroundings in order to make their preservation possible. For instance, human beings obtain energy by eating and breathing and then use that energy to build homes and civilisations. Much the same can be said of bacterium absorbing food and reinforcing its cell structure.

Then, the ability to reproduce is one of the distinguishing characteristics of living organism, albeit their aims may be as sophisticated as that of human beings or as simple and basic as a virus or a bacterium. The physical basis of life is the chemistry of the carbon atom because this atom can bond with other atoms, it can form long, complex, stable chains that are capable of extracting, storing and utilising various energy forms. In order to understand life we must first understand the basic attributes of carbon. All life is carbon-based.

But first what remains to be said about life’s history; the oldest fossils indicate that life began in the seas, or shallow waters. The oldest identifiable fossil appear in the sedimentary rocks over 1/2 billion (500 million) years ago. In the Cambrian Period (named after the hills of the same region, where they were first discovered), these were the simple ocean creatures, like tribolites. There are no land fossils of land plant, or animals of the same or equal period. Land surfaces were totally devoid of life until 400 MYA.

Pre-Cambrian (pre- 500 million years ago period), fossils have been revealed by microscopes as micro fossils that were essentially the ancestors of the Cambrian creatures — roughly speaking bacteria and simple algae.

Apparently, such life was already active in the earth’s oceans a billion years after the earth formed that is a full 3.6 BYA. Now lastly, what remains of carbon as originator of life; the basic unit of life on the earth is the cell. The self-contained factory is capable of absorbing nourishment from its surroundings, maintaining its own existence and performing its multiple tasks within the larger organism. The foundation of the cell’s activity is a set of patterns that describe how it and others of trillions of cells of the same type are to function as a whole. For the rest of what life is and what part carbon plays in sustaining it, let’s meet in the next issue!