Perspectives

Some astronomers tell us that the Universe contains 10,000 times as many stars as there are grains of sand on Planet Earth. One of these stars is our Sun.

Let us suppose there are, on average, two planets for every star (there are probably more than that), then that gives us 20,000 times as many planets as there are grains of sand on Earth.

The Sun has eight planets. Moving outward from the Sun. They are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

The Earth, which is believed to be about 4.5 billion years old, proved to have the most amazing properties. Over time, this primeval hodgepodge of rocks, water, gases and energy, generated life, in all its diversity and complexity.

Let us suppose that one percent of the planets in the have a similar constitution to the Earth, and are at a similar temperature, then there would be 200 times as many Earth-like planets in the sky as there are grains of sand globally.

Since these planets would have the same material constitution as the Earth, and since they are subject to the same laws of physics, it is reasonable to assume that that they would share the same properties. This would mean that they could generate, and sustain, life.

Let us focus on Planet Earth. The earliest living organisms are believed to have come into existence around four billion years ago. They were single-celled microbes, and they were the most complex form of life for over 1000 million years.

Multicellular organisms like seaweeds, sponges, jellyfish, corals, worms, molluscs, sea urchins, and starfish came into being 600-700 million years ago.

Since that time, biological evolution has resulted in the coming and going of myriads of life forms, leading to the rich network of organisms that live in our world today.

Until around 400 million years ago, biological evolution was taking place in the oceans, but at around that time some living organisms were moving onto the land.

The dinosaur era, which began around 200 million years ago, lasted until 66 million years ago, when a mass extinction wiped out every one of the hundreds of dinosaur species, as well as numerous other kinds of animals. Some species of birds, which are descended from dinosaurs, survived, as well as well as some lizards, tortoises, crocodiles, mammals and invertebrates.

Estimates of the number of different species alive today are very variable. The most commonly cited figure is 8.7 million, although some authorities believe the number is much greater than this.

Some common features shared by many animal species go back a very long way in evolution. The mouth and anus were in existence 600 million years ago. Among vertebrates, two eyes, two ears, a heart and a stomach go back at least 550 million years; and four limbs with three to five digits go back to the earliest amphibians 360 million years ago.

During the last part of the dinosaur era there existed a small group of tree-dwelling primates that looked something like present-day shrews. Among them were the ancestors of humankind. Five or six million years ago there were some much larger primates walking in the African savannah with an upright posture.

Two and a half million years ago, and perhaps considerably earlier, there were primates in Africa making stone tools. One species, called Homo habilis, was 90-120 cm tall, and it had a brain with a volume of about 800 cm³, which is about 300 cm³ larger than the brain of a chimpanzee.

After that, several different human species came into being.

The earliest ‘modern humans’, Homo sapiens, were living in parts of Africa around 300,000 years ago. They were tall people, with rounded skulls and steep foreheads, and their average cranial capacity was about 1,400 cm³.

From about 200,000 years ago, Western Europe was occupied by a distinctive form of humanity classified as Homo neanderthalensis. The brains of adults ranged from 1,450cm³ to 1,650 cm³ in volume. They were well acquainted with the use of fire, and they hunted big game and dressed in animal skins. They used paints to decorate their bodies and sometimes they buried their dead.

Homo sapiens moved into Europe 40,000-50,000 years ago, displacing and interbreeding with Neanderthals.’

Apart from the Neanderthals and Homo sapiens, there were at least at least three other kinds of humans living outside Africa at that time. Homo longi was in China,and remains of Homo denisova have been found right across Asia. Although they are classified as a distinct species, both the Neanderthals and the Denisovans interbred with Homo sapiens. Dwarf hominids, called Homo floresiensis, occupied the island of Flores in Indonesia until about 50,000 years ago.

Only Homo sapiens remains today.

Modern humans possess an extremely important attribute that is unique in the animal kingdom today. It is the ability to invent, remember and communicate with a symbolic spoken language. This aptitude for language led to the accumulation of shared worldviews, knowledge, beliefs, attitudes and technological knowhow in human groups. That is, it led to human culture, which has recently become a powerful force in nature. It has led to activities that have been to the benefit of humans, and it has led to activities that are greatly to our disadvantage.

The history of Homo sapiens can be seen as consisting of four quite distinct ecological phases.

Phase 1, the Hunter-gatherer Phase, began with the origin of our species around 300,000 years ago. It still exists in some places, such as Paraguay and Tanzania.

Phase 2, the Early Farming Phase, began in several parts of the world around 10,000 to 12,000 years ago. This means that for over 97 per cent of our species’ time on Earth, all humans were hunter-gatherers.

Farmers, unlike hunter-gatherers, were no longer continually on the move. Their lifestyles often involved long periods of hard physical work.

The introduction of farming marked a turning point in cultural evolution. It was a precondition for all the spectacular developments in human history that have taken place since that time.

The third ecological phase, the Early Urban Phase, began around 9,000 years ago, when large clusters of people, sometimes consisting of several thousand individuals, began to aggregate in townships. Many of these people played little or no part in the gathering or production of food. Occupational specialisation became the hallmark of urban societies.

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

Ecological Phase 4, the Exponential Phase, is also called the Anthropocene. It began around 250 years ago, and it thus represents less than one per cent of Homo sapiens’s time on Earth. It has seen an astounding profusion of technological innovations – from steam engines and motor vehicles to intercontinental rockets and spacecraft – and from electric lights, telephones and radios to thermonuclear bombs, computers, smartphones and the Internet.

The Anthropocene has been associated with a massive and continuing growth in the human population, and an even more explosive increase in resource use and waste production by humankind. There are now over 8 billion people on Earth, which is about 1,600 times as many as there were when farming began. Nearly 90 per cent of this increase has occurred in this ecological phase. The global population is still increasing at the rate of 1.4 million per week.

Humankind is now responsible for the emission 37 Gigaton of carbon dioxide per year, which is 180 times what it it was in 1800. The figure is still increasing by about one per cent peach year.

Deforestation of tropical forests is occurring at an ever-increasing rate − mainly to make way for oil palm plantations and pastures for beef cattle.
Only about 6 million km² remain of the original 16 million km² of tropical rainforest that formerly existed on Earth. Over 30 million acres of forests are lost every year.

Lethal combat has presumably occurred from time to time throughout the history of humankind. Before the invention of gunpowder, the weapons used were for killing one person. The Hiroshima bomb, which was dropped in 1945, is estimated to have killed 140,000 people. Bombs are now in existence with an explosive power a thousand times greater that of the Hiroshima bomb.

One does not have to be an ecologist to appreciate that human activities are now of a kind and on a scale that threaten the survival of civilisation, and perhaps the survival of the humankind.

The future wellbeing of humankind will require revolutionary changes in the worldviews and priorities of the prevailing cultures across the world. Herein lies the great challenge of our time.