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An evolutionary perspective

Our planet is about 4.6 billion years old. The sun provides it with a constant supply of energy – in the form of rays of visible light and ultraviolet and infrared radiation.

The history of life on Earth has been marked by a series of crucial watersheds, each with enormous consequences for the future of the biosphere.

The first watershed, over 4,000 million years ago, was the appearance of the earliest forms of living organisms. They were single-celled bacteria and were the most complex form of life on Earth for over 1000 million years.
Then, around 2800 million years ago, micro-organisms capable of photosynthesis emerged. Apart from providing energy for life on Earth as we know it today, these organisms released free oxygen into the atmosphere. Some of this oxygen became converted into ozone which floated up to the stratosphere where it acted as a filter, protecting the Earth’s surface from ultraviolet radiation from the sun.

Other watersheds include the appearance of multicellular organisms between 600 and 700 million years ago, the colonisation of land by plants and animals around 400 million years ago, and the first flowering plants 160 million years ago.

The history of life has also been marked by a number of mass extinctions, the most severe of which occurred around 250 million years ago when around 95% of all marine species and 70% of land species were wiped out. Another mass extinction took place about 65 million years ago when many forms of life disappeared, including all the dinosaurs and flying reptiles. Some groups of reptiles survived, including the snakes, lizards, crocodiles and turtles.

Some birds and mammals also survived, and during the next 50 million years there occurred an extraordinary diversification in these two groups. By 6 million years ago there were upright-walking primates in Africa.

Some milestones of biohistory

Our existence, and that of all other animals, is entirely dependent on the growth of green plants — because plants, through photosynthesis, capture light energy from the sun to manufacture the complex energy-containing organic molecules on which life depends. Nearly all this energy ultimately leaves the biosphere in the form of heat.

An essential characteristic of life on Earth is the cycling of the nutrients that are taken up from the environment, built into the tissues of living organisms, and then eventually released again to become available for incorporation into new life. These nutrient cycles are essential for the sustainability of life.The organic content of soil is essential for maintaining soil fertility. It consists of decomposing plant and animal matter as well as a profusion of different kinds of living organisms.

There are thought to be some 7 to 15 million different species of living organisms on Earth today. About half of them may be extinct by 2075 as a consequence of human activities.

Humans in nature

At the time that the dinosaurs disappeared, about 65 million years ago, there existed on Earth a small group of shrew-like, tree dwelling primates. Among them were the ancestors of humankind.

By 180 000 years ago people with the physical characteristics of modern humans, and classified as Homo sapiens, were in existence in Africa. By 60 000 years ago the species had reached Australia. About 45 000 years ago Homo sapiens displaced another human species, Homo neanderthalensis, in Europe.

Over the millennia, and as our species spread across the globe, some divergence occurred in the genetic characteristics of human populations, resulting in observable physical differences between people living in different parts of the world.

An extremely important feature of the evolution of Homo sapiens was the development of the human capacity for culture, and consequently the gradual emergence of human culture itself. [2]

The most essential aspect of this capacity for culture is the ability to invent symbolic language and to use it for exchanging information and ideas, and so to create, accumulate and share knowledge, beliefs and assumptions.

The ability to invent new technologies and to pass on this technical knowledge from one individual to another and from generation to generation is also often regarded as an aspect of culture.

The evolutionary emergence of the capacity for culture represents one of the watersheds in the history of life on Earth. Others included the emergence of life itself, the development of photosynthesis and advent of multicellularity. Human culture emerged as a new kind of force in nature, and it has had far-reaching consequences not only for humankind but also for the rest of the living world. All the major threats to humankind today, including global climate change and weapons of mass destruction, are the consequence of the human aptitude for culture.

One of the outcomes of the capacity for culture was the emergence of religion, involving belief in supernatural spirits, gods or a god. Religion became a universal feature of human societies, although there has always been enormous variation in the details of the different belief systems, and differences in religious beliefs have been, and still are, a major cause of violent conflict between human groups. However, in our society today many people do not accept any religion.

Four ecological phases

The history of Homo sapiens falls into four distinct ecological phases:

Phase 1 − The hunter-gatherer phase

The human species emerged as a species adapted biologically to the conditions of life of hunter-gatherers, and the hunter-gatherer phase was by far the longest of the four ecological phases.

Ecologically the most important culturally-inspired activities in this phase were the deliberate use of fire and the manufacture and use of tools and weapons.

As in the case of all other animal species living in their natural habitats, most of the time most members of hunter-gatherer bands are likely to have been in a state of good health. Indeed, they had to be in order to survive and successfully reproduce under the demanding conditions of their lifestyle and environment.

Although bacterial infections after injuries would have been a constant hazard, because of the relatively low population density people would not have suffered from such respiratory and enteric virus infections as colds, influenza, gastric flu, measles, smallpox and German measles. Nor are they likely to have experienced bacterial infections like cholera, plague or tuberculosis.

Phase 2 − The early farming phase

Homo sapiens had probably been in existence for at least 170 000 years before farming began in several parts of the world around 10 000 to 12 000 years ago. This development marked a turning point in cultural evolution. It was a precondition for all the spectacular developments in human history since that time.

Phase 3 − The early urban phase

This phase began around 9000 years ago when fairly large clusters of people, sometimes consisting of several thousand individuals, began to aggregate together in townships. Many of these people played no part in the gathering or production of food.

Although the new conditions offered protection from many of the hazards of the hunter-gatherer lifestyle, malnutrition and infectious disease became much more important as causes of ill health and death.

Phase 4 - The high consumption phase

This phase was ushered in by the industrial revolution, which began a little over 200 years ago. It has been associated with profound changes in the ecological relationships between human populations and the rest of the biosphere. The following developments have been especially significant:

• the introduction of machines that use extrasomatic energy, mainly from fossil fuels, for performing various kinds of work [3]
• the discoveries and applications of electricity and radioactivity
• the spectacular growth of the chemical industry
• the invention and manufacture of weapons of mass destruction.

Phase 4 has seen a marked increase in human life expectancy, especially in the developed world – due mainly to improved hygiene and nutrition, but also to immunisation and the use of antibiotics.

The global population increased from about 1 billion in 1800 to 2 billion in the 1930s; and it is now approaching 7 billion. This massive growth of the human population as well as the explosive increase in intensity of techno-industrial activities are resulting in progressive ecological disturbance across the whole planet. We are now living in the final part of this fourth, high consumption, phase of human existence. It is simply not sustainable ecologically.

Homo sapiens evolved as a hunter-gatherer

Our species has been in existence for some 8000 generations and we are basically the same animal today as our ancestors who lived long before the advent of farming – that is, an animal genetically adapted through natural selection to the life of the hunter-gatherers. This fact has many important implications for our understanding of ourselves and our problems.

We have the same innate health needs and the same innate behavioural characteristics as our hunter-gatherer ancestors.

However, the vast majority of the human population today live under conditions very different from those to which our species is biologically adapted through evolution. Many of the forms of ill health in modern society are a consequence of this fact. There have been too few generations exposed to life in cities for there to have emerged a new breed of humans better adapted to urban living.

Human culture as a force in nature

The most distinctive biological attribute of our species, the human capacity for culture, was of major biological advantage in the evolutionary environment of the species, and in more recent times ithas resulted in an amazing increase in the number of humans on Earth.

Apart from its practical advantages, culture adds richness to human experience. It did so in the days of our hunter-gatherer ancestors – as in story telling, musical traditions, dancing and other forms of artistic expression. It does so today in so many ways. Culture makes a huge contribution to the sheer enjoyment of life.
But there is another side to the picture. The consequences of our capacity for culture are not all good. Culture has also been responsible for an immense amount of human suffering.

In fact, as cultures evolve they have often come to embrace not only factual information of good practical value, but also ideas and assumptions that are sheer nonsense, leading to behaviours which are equally nonsensical.
Sometimes these cultural delusions have resulted in activities that have caused a great deal of unnecessary human distress, or damage to ecosystems, or both. We refer to culturally inspired activities with these characteristics as cultural maladaptation.

There are countless examples of this in human history. [4] And today all the main threats to human wellbeing and survival are consequences of cultural maladaptations.

Here our focus is mainly on the ecological predicament.

Cultural maladaptations today

Among the undesirable consequences of our aptitude for culture is the fact that culture has separated us, mentally, from the rest of the biosphere. Instead of feeling part of nature, humans tend to see themselves separate from, and even as in some way superior to, the rest of the living world. This mindset effectively blocks social reform aimed at achieving ecological sustainability.

The worldview and assumptions of our dominant culture today are resulting in cultural maladaptations on a scale and intensity never seen before in the history of humankind − maladaptations that are totally incompatible with the survival of civilisation.

There are two sets of changes underlying the major ecological difficulties facing humankind today:

1. The massive increase in the human population. There are now about 1000 times as many people on Earth as there were when our ancestors first started farming, putting enormous pressures on the food-producing ecosystems of the biosphere. 5000 million of the present 6700 million people now in existence were added in the past couple of hundred years, and the UN forecasts that another 2-3000 million will be added by 2050.
2. The explosive intensification – especially in the developed countries – of energy and resource use and technological waste production following industrialisation associated with consumerism and economic growth.

In addition to these ecological issues, the manufacture of weapons of mass destruction constitutes another horrendous threat to our future. According to recent estimates, there are around 25 000 nuclear warheads in existence. It would not take many of these to bring an end to civilisation as we know it. The cultural maladaptations of the present era are a direct reflection of the worldview, assumptions and priorities of the dominant cultures of our time.

Ultimate biological limits − an important biohistorical principle [5]

Through their capacity for culture, humans have long been consciously manipulating the processes of life to their advantage – or to their perceived advantage. Up to a point, nature permits these culturally-inspired manipulations. Indeed it offers considerable scope for people to enrich their lives through culture.

However, there are limits and these are determined by the simple rule that the essential underlying processes on which life depends must not be violated.

For example, the biochemical and physiological processes inside our bodies on which our health depends must be kept intact.

We can modify our diet up to a point to our advantage – as in the practice of the culinary art. But if we omit essential nutrients like ascorbic acid, or if we add certain unnatural chemical agents, we fall sick and may die.
We can also somewhat modify our natural sleeping patterns. But there are limits. If we are deprived of sleep for too long we cease to function biologically.

Similarly with the natural environment – the essential ecological processes on which all life depends must be kept intact.

We can practice farming to our advantage. But if we seriously disrupt the natural nutrient cycles, or if we interfere with soil biology so that bacteria and other organisms can no longer play their crucial role in these cycles, then productivity will cease.

Or if we discharge chemical pollutants into the environment that interfere with essential life processes, either directly through poisoning life forms, or indirectly, by changing the climate – then the life support system on which we depend will ultimately collapse.

If we overstep the mark by interfering with the essential processes that underpin the whole living system, then we are in big trouble. There are many instances when this has happened in the past.

Today our society is transgressing these biological limits on a scale never seen before. And we are indeed in big trouble.

Urgency

Clearly, there are limits to the amount of damage that humankind can do to the ecosystems of the biosphere before they cease to be able to support civilisation. The crucial question is: How far are we from reaching these limits?

Opinions differ on the answer to this question. A middle view is that of the Union of Concerned Scientists (UCS) who have stated that:

‘No more than one or a few decades remain before the chance to avert the threats that we now confront will be lost and the prospects for humanity immeasurably diminished’.

An important report known as the Millennium Ecosystem Assessment (MA) was published in March 2005. It was called for by United Nations Secretary-General Kofi Annan in the year 2000. It involved the work of 1360 experts around the world. The following excerpts from the statement from the Board governing the MA process summarise some of its conclusions:

‘At the heart of this assessment is a stark warning. Human activity is putting such a strain on the natural functions of Earth that the ability of the planet’s ecosystems to sustain future generations can no longer be taken for granted.

‘Protecting and improving our future well-being requires wiser and less destructive use of natural assets.
‘We must learn to recognise the true value of nature – both in an economic sense and in the richness it provides to our lives in ways much more difficult to put numbers on.

‘Above all, protection of these assets can no longer be seen as an optional extra to be considered once more pressing concerns such as wealth creation or national security have been dealt with.

‘This assessment shows that healthy ecosystems are central to the aspirations of humankind.

‘… this is not a counsel of despair. The natural balance sheet we bequeath to future generations depends on choices made at every level and in every corner of the planet.’

With respect particularly to climate change, it now transpires that we have only a decade or two to act in order to avoid catastrophe, by drastically reducing the emission of greenhouse gases and by sequestering carbon through forestation and other means.

The necessity for big changes

If present trends in human activity continue, the ecological collapse of human society is inevitable.

It is abundantly clear that the human species is overstepping the mark in a big way. Present patterns of human activity are not ecologically sustainable – and therefore not sustainable in any other way. Continuing business as usual will inevitably mean the disintegration of civilisation.

Biounderstanding thus highlights the fact that the survival of civilisation will require very big changes in the patterns and scale of human activity on Earth and that these changes will not happen unless there come about major shifts in the worldviews and assumptions of the dominant cultures across the globe.

Paramount among the maladaptive ingredients of the dominant culture of our own society is the belief in ever-moreism – associated with an economic system which results in rampant, ever-increasing consumption of resources and consequent discharge of technological wastes. This ideology is ecologically insane. It is leading us faster and faster towards ecological catastrophe.

Notes

Papers in this series
1. Prologue
2. Biological background (this page)
3. A vision for the future: biosensitivity
4. What’s wrong today - a thumbnail sketch
5. The transition to a biosensitive society
6. Some crucial perspectives
7. A transition framework

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2.  The word culture is used here to mean the abstract products of the capacity for culture, such as learned language itself and the accumulated knowledge, assumptions, beliefs and values of a human population. Back to text

3.  Extrasomatic energy is energy which is used outside the human body, as distinct from the somatic energy which is consumed in food and which flows through the body. Back to text

4. See S. Boyden. 2004. The biology of civilisation: understanding human culture as a force in nature. UNSW Press. Sydney. Back to text

5. Biohistory is the study of human situations, past and present, against the background of the story of life on Earth. Back to text