It may seem somewhat out of place to discuss the origin, evolution and diversification of life in the context of a symposium on humanness. Nevertheless, concerns for our environment are important, since the wellbeing of humans is tied to that of the environment. With this in mind, I will try to describe the benefits of diversity and a few risks that could be waiting for us down the road.

First, a few words about the way science operates. Science is not a collection of truths, but rather of facts. The facts are derived from observation or experimentation and reported so that others can repeat the experiments. The base of facts or observations is the more permanent part of science, while the structuring of these facts to produce meaningful contexts is an ongoing process. Hypotheses and theories based on the facts are put forward, tested and then either accepted or discarded. Theories that have passed the tests may then become principles or laws. However, no principle or law is permanent. If new data, or new theories, conflict with a principle, it must be revised or discarded. J. DuPraw described the scientific method as follows,

For thousands of years it was widely held that life originated through spontaneous generation; life just came into being. In other words, if you left a pot of water out long enough, before long it would be teaming with life. This theory was debated until 1864, the year in which Louis Pasteur received the Paris Academy of Sciences prize for experimentally disproving this theory by demonstrating that a boiled nutrient rich broth sealed in a sterile environment would not produce any sign of life no matter how long it sat.

The current understanding of the origin of life consists of the gradual emergence of organic molecules and life processes from a specific non-living environment; such as the one that existed on the newly formed earth.

The environment on the newly formed earth was rich in energy: geothermal energy from the still cooling earth; electrical energy in the form of lightning; and radiation, as well as a flux of ionised particles, from the sun. Since there was no oxygen to block its passage, energy-rich ultraviolet radiation reached the surface. Hydrogen, carbon, nitrogen and oxygen were all present in the primitive atmosphere: the four elements, which make up 95% of the tissues of modern living organisms. The atmosphere at that time was in a process called reduction. At first, there was no free oxygen, for it was bound up in water. Later, free oxygen became available. It began accumulating from inorganic sources, but once photosynthetic plants began to emerge its presence increased rapidly.

It has been argued quite convincingly that before life actually originated, there was a long period of chemical evolution. Very simply, during that time carbon (C), nitrogen (N) and oxygen (O) were hydrogenated (that is, these elements bound themselves to Hydrogen) to form methane (CH₄), ammonia (NH₃) and water (H₂O). This mixture of gases and water vapour was bombarded by ultra-violet rays and particles from the sun, then exposed to intense electrical discharges at high ambient temperatures. These gases were ionised and later recombined to form new molecules. As these new molecules were exposed to the same energetic environment, new ionisations occurred and more new molecules were formed. Over a long period of time, in the range of a billion years, a variety of molecules and ions were formed. Many of these are what we today call organic compounds. Later, as the earth cooled, the water vapour condensed and fell in heavy rain, with the result that the gaseous compounds were washed from the atmosphere into pools on the surface, leaching minerals out of the rocks.

Thus simple acids, amino acids and alcohols were brought into solution. New sets of conditions were now operating, modifying and complicating the washed-out compounds further. Evaporation from pools, adsorption of clay minerals and conditions on and near beaches brought about a concentration and further complication of the organic compounds in a 'soup.'

It is difficult to design experiments that demonstrate the steps of the origin of life. Beginning in 1952, however, however, Stanley Miller performed, one important set of experiments, which supports the formation of amino acids, the building-blocks of proteins, under conditions believed to be similar to those of the primitive earth.

Miller used two connected containers. Water was placed in the lower one and ammonia and methane gases in the upper one. Thus the four basic elements (Carbon, Oxygen, Hydrogen, and Nitrogen) which make up most of the tissue of all living things today were present in the two containers. The lower container was set up so that it could be heated, and the upper one had electrodes inserted in it to imitate lightning discharges. When heated, the water evaporated and rose into the upper container. Here the gas and water vapour mixture was subjected to electrical discharges. When the water vapour condensed, it dissolved any compounds that had been formed and washed them down into the lower container. After 24 hours, 45% of the methane carbon, originally in the upper chamber, had been converted into amino acids (such as Glycine, which make up proteins the building blocks of cells) as well as other organic molecules (ex., Oxalic acid), which were recovered from the water in the lower container.

Given the presence of the variety of organic compounds on earth, and the prevailing energetic conditions, at some point, during the evolution of the first organisms, cell membranes were formed. If molecules similar to the lipids that form membranes in contemporary cells were formed when the first cells were evolving, the formation of membranes would have been spontaneous. Lipids are molecules which are hydrophilic (water loving) on one end, and hydrophobic (water hating and therefore oil loving) on the other. In a water solution the oil loving ends will join together in the centre, leaving the hydrophilic ends exposed to the environment, hence a barrier or membrane is formed. This has been demonstrated experimentally for the lipid molecules that make up the membranes of present-day cells. In fact, this arrangement of lipids may be clearly seen when our cells are viewed under an electron microscope. This hydrophilic / hydrophobic arrangement makes the cell quite versatile, allowing the presence of quite a variety of chemical compounds to exist and chemical processes to occur, where the water or waterless needs of these chemicals or processes are all met within the boundary of the cell.

During the period when life originated, two things were missing. There was no life and there was no oxygen. Indeed, the environment would have been hostile to any living organism today. It is obvious that there could have been be no living organisms. If there had been anything resembling our present-day communities of microorganisms, these would have devoured any organic compounds and incipient life forms thus ending the evolutionary process. The other specific condition that bars life from originating today is the oxygen in the atmosphere. The reducing (oxygen-less) conditions of the primitive earth were essential for the formation of the first organic molecules.

Conditions since these first beginnings, however, have been favourable for the successful perpetuation of life over time until the present. Not only has life persevered, it has evolved, differentiated. Presently, there is such a variety of life, that scientists have developed a system of naming the various forms of life.

To classify the vast numbers of species, a binomial system has been adopted, which means each species is given a double name. Modern humans belong to the species Homo sapiens. The first name gives the genus, the taxon or grouping a level above the species, and the second name indicates the species. The genus Felis includes ocelots, lions, and cougars. The domestic cat is Felis cattus.

The classification system is hierarchical and has a number of higher taxa: species, genus, family, order, class, phylum and kingdom. The phylum, meaning branch, refers to the notion that organisms are monophyletic, that the kingdoms originate from a common ancestor from which the phyla radiate as the branches of a tree. The number of kingdoms varies depending on the school of classification. Beside the kingdom Animalia, four others may be listed: the Monera (bacteria, blue-green algae and viruses), the Protista (protozoa, algae and slime molds), the Fungi, and the Plantae.

The species is the taxon that is most easily defined, as it has the ability to reproduce–to have viable offspring. The phyla, the main branches on the phylogenetic tree, have major characteristics in common, such as the articulated exoskeleton of the phylum Arthropoda.

Homo sapiens belongs to the family Hominidae, order Primates, class Mammalia, sub-phylum Vertebrata, phylum Chordata, and kingdom Animalia.

In the process of evolution new species appear and numerous species die out. Even higher taxa die out and new appear. The major reason for dying out is an organism’s, specie’s or taxa’s incompatibility with the environment and the inability to adapt. A dying out often involves competitive exclusion, where a species cannot hold its own in competition with another species with very similar requirements on the environment. This might happen after a change in environmental conditions, or after changes to the species itself. The two species could also be said to be competing for the same niche in the ecosystem. When, as a consequence, niches are left unoccupied existing species specialise to fill the empty space. This can lead to speciation–the evolution of a new species.

Life has adapted to all possible locations on the earth. Indeed, there is no surface on earth that is devoid of life. Some form of life always finds a foothold–from pole to pole, from the highest mountain peaks to the deepest ocean trenches. The biosphere covers the globe and reaches roughly ten kilometres above (the height of Mt. Everest) to the greatest ocean depths. Climatic extremes and extremes in surface conditions have all been conquered. Even pools of seeping petrol have their unique inhabitants. This obviously calls for the evolution of a great variety of organisms; each adapted to its specific environment.

Animals, for example, have evolved from the unicellular (protozoa) to those with millions of cells, organised into tissues and organs. Animals can be built on a radial body plan (e.g., polyps), or this plan can be bilaterally symmetrical as in humans. Each adapting to its specific place in the Biosphere; serving its specific purpose or niche.

Organisms have developed countless adaptations to survive in the different habitats. For animals these adaptations involve the body surface, senses, locomotion, digestion, respiratory and circulatory systems, etc. Plants have developed a system for photosynthesis (root systems, stems and leaves), which plays a role in the survival of the majority of living things.

Most of the energy needed to sustain life on earth comes from the sun in the form of radiation. This energy heats both the atmosphere and the surface. The energy that is needed for organisms to function and to grow is captured by plant pigments and drives photosynthesis, the basis of food production and the replenishment of life-sustaining oxygen in the biosphere. It is interesting to note that only a fraction (at most 1-2%) of the radiated energy that reaches the surface is utilised by the plants.

The total number of species is enormous. For a long time, it was held that there were approximately one million animal species, but a closer look at the extremely diverse biota of the tropics, especially the rain-forests, increased this number, perhaps by a factor of ten. The vast majority of these new species belong to the Insecta, which is the most successful of all major groups of animals, with adaptations to withstand the most adverse environmental conditions, and with species that have developed important social structures. The vast majority of these new species have not been described.

The current understanding of ecology is the study of the interactions between organisms, and between organisms and the non-living environment. As the entire biosphere would be too large, and hold too much variation, it is more convenient to study an ecosystem. An ecosystem is a restricted entity, where the various components interact regularly and where there is a flow of energy through the system, as well as a cycling of minerals. Thus the type of bedrock and the climatic conditions determines soil type. This in turn determines the plant community that can live there, and the plant community determines which animal societies can establish themselves. Changes to climate, or other environmental characteristics, will necessarily bring with them changes in the plant and animal societies.

The sum of interactions between organisms and the physical environment may be summarised as an interface. Humans have such an interface as have all other organisms. As each individual has his or her own interface, populations and communities have their own. The needs that have to be satisfied across these interfaces depend on which unit is under observation: an individual, a community or, for example, all of humanity. To satisfy a need interaction is necessary and there has to be something or someone with whom to interact: be it vegetables for food, minerals for industry or enemies from which to protect oneself.

If our environment can be kept at a high degree of diversity, the number of possible interactions will be high. We cannot predict what kind of needs we will have in the future, as life is constantly evolving. Thus a diverse, evolving environment will increase the possibility of satisfying our future needs. A species that is fully interacting in evolution will be in balance with the existing environmental factors.

In the ecological scenario called the survival of the fittest, the organism fit to survive can be said to be the one that can counteract sufficient negative interactions (e.g., flu virus) and secure sufficient positive ones (e.g., provision of food). This could also be translated into an energy budget, which at all times must show a positive balance, or the organism will cease to exist–no overdrafts would be allowed.

Before the emergence of modern genetic methodologies, organisms evolved, changed and survived in harmony with nature, or, in Darwin's terminology, according to the law of the survival of the fittest. It was Gregor Mendel (1822-1884), who provided the genetic background to how organisms actually changed by discovering the gene. There are different genes in plants and animals, which affect their appearance.

Breeding is an old art. Its mechanism had been described, beginning with Mendel's discovery of the hereditary unit, the gene. More insightful work arose in the field of selective breeding. As the term implies, the method involves selecting a preferred variety of a species over those with less desirable characteristics. For example, among animals, the dog, Canis familiaris, has been bred into about 100 varieties, such as the collie, beagle and greyhound. Another well-known example of selective breeding has been performed on the species Brassica oleracea, which has been bred to give such familiar varieties as Kale, broccoli and cauliflower. In each case, an aspect of the original plant was selected. So kale was bred for its leaves. Brussel sprouts for their lateral buds. Broccoli was selected for the stem and flowers, kohlrabi for the stem, cabbage for one terminal bud. Since these are artificial systems, a sustained effort is needed to keep them from reverting to the natural or wild type. To do this, a continuous input of resources is needed.

The next major discovery in the field genetics was the genetic code (the double helix) by J.D. Watson and F. Crick, in the 1950s, opening up almost unlimited possibilities for genetic improvement in areas related to health, the food industry, etc. Modern gene manipulation technology combined with improved micro-manipulation techniques has now, almost 50 years later, made it possible to change a genome and to transfer genes, chromosomes and entire genomes from one cell to another. This makes it possible to make transfers that never could occur in nature, including the cloning of individual organisms. The genetically modified organisms will not be 'natural' of course. If the changes to their genomes are substantial enough, these organisms would probably die out if they were returned to uncontrolled environment and subjected to natural selection.

While we have reaped many benefits from genetic manipulation, natural selection can also have a seriously negative effect on human populations. For example, since antibiotics came into wider use, more than 50 years ago, pathogens have been developing a resistance to these drugs. This could be said to be a case of unintentional breeding.

The discovery of penicillin provided an important weapon in the fight against infectious disease. Many pathogens were easily controlled with this antibiotic. But, as is the custom of humans, we overreacted. Antibiotics were soon prescribed whenever someone had a sore throat, irrespective if caused by a bacterial infection or by a virus (which are not susceptible to antibiotics; that is, antibiotics are not effective). This ample supply of antibiotics actually selected resistant bacteria: it killed non-resistant bacteria, leaving resistant bacteria, which would then reproduce. This is a breeding program in disguise, the results of which are the so-called super-bugs, pathogens that are resistant to antibiotics.

A breakout of a super-bug would actually bring humans back into the realm of natural selection. An epidemic could develop comparable to the Black Death, which in its time (ca. 1350 CE) reduced the population of Europe by as much as one third. People who are either isolated, or who have the proper immuno-competence to protect themselves from the super-bug, would survive. Such an epidemic would most likely be more devastating to western societies, as the use of antibiotics has been widespread in these cultures over a long period of time.

In an alternative scenario, science and medicine could prevent any serious damage to the society. Each new threat to human health would be countered by the medical sciences, and, should the countermeasures prove successful, the society would survive. The society, however, would also be increasingly distanced from 'natural' conditions. We are already fairly separated from the environment. We have built houses. We have corrected near-sightedness with glasses (indeed, a great number of the population would have great difficulties if it were not for glasses). We are no longer fully in the natural selection process, and we have prospered nevertheless. The further the distance from 'natural' conditions, the more energy needed, in terms of medical and technological resources, to compensate for the imbalance.

For example, everyone agrees that something needs to be done about the super-bugs, though no one seems to be sure what course of action to take, or which actions are cost feasible. Research, development and implementation take time, therefore reform is very expensive. So in terms of monetary costs we ask, can we afford it? Do we have the money to put into defending ourselves from threats?

As each new threat increases costs, our societies are increasingly at risk of succumbing to sudden disruptions of these protected environments. This scenario fits nicely into the framework of natural selection: a species evolves and finds itself in a situation it cannot control, a cul-de-sac. Outside its protected environment it dies out–a situation analogous to the one we sometimes hypothesise for the dinosaurs. The actual extinction of the human species, however, will most probably not occur.

There is a conflict between the immediate benefits of technology versus the need to avoid damage to the natural environment, if we are to receive still more benefits from it. Quite apart from the immediately obvious benefits, such as harvesting crops of grain and fish, there are other ways in which we utilise nature.

For example, we use certain species of the plant or animal kingdoms to extract medicines. Many medications trace their origins back a long time (e.g., the Foxglove gives us digitalis), while others are the result of dedicated research in more recent times. Pharmaceutical companies are constantly examining ocean communities and rainforest biota for chemical compounds, which may provide starting material for new medicines.

Many organisms use chemicals in interactions between species. Hence toxins are used for defence and to immobilise prey. Pheromones are used for the regulation of behaviour and populations. These same compounds have been successfully utilised in forestry, for example, to fight pests.

A large number of industrial processes are based on biotechnology. The most versatile organisms in these applications are micro-organisms. Cheese and beer are well-known examples. Other examples include enzymes used in industry; and medicines, which are currently produced by gene-manipulated micro-organisms.

We can also look to nature for bioindication. When it is known how species, populations and components of biota behave relative to anthropogenic stressors, such as pollution for example, it is possible to detect such impacts early by observing indicator organisms. As long as the environment can keep a high level of diversity, there will be such organisms practically everywhere.

The extent to which we make use of biology in everyday life can be seen from the sheer numbers of bio-related mechanisms, such as Bio-degradation, Bio-remediation, Bio-accumulation, and Bio-magnification.

There are numerous reasons for protecting biological diversity and a healthy environment. I have tried to highlight a few of them: the indirect benefits from a future, vigorously evolving environment that will provide selections of compounds for industry and much more. And the direct benefits that we can harvest today.

To fully benefit from a good environment we should be part of it ourselves. This may not be an easy undertaking, as there are already compelling reasons to distance ourselves from certain aspects of the environment. Most of these are medical: we need protection from the ultraviolet rays of the sun, for example, and we need to protect ourselves from allergens and other agents that cause allergies and environmental hypersensitivity.

A number of questions need to be decided upon today, and more questions are likely to emerge in the days to come. With our increasing ability to change our environment and, indeed, ourselves, there comes the obligation to take responsibility for our decisions. To do this in a reasoned fashion we have to have information, but we also have to be familiar with the possible scenarios that might arise for us in the future. As we now move even further from the process of natural selection costs increase, our societies are increasingly at risk of succumbing to sudden disruptions of these protected environments. Perhaps we bring humanness to this by finding ways of coping with the threats. We must be made aware of the problems in order to discuss them and reach some consensus as to where to allocate resources. As the environment and we are evolving, so also may the solutions to our problems be currently evolving. When it comes to protecting the diversity of our environment, or coming up with strategies to deal with the problems associated with our own distance from the process of natural selection, we ultimately need to ask the question, do we let the bottom line rule all our sensible decisions?