2. From nature to culture
But humanity’s total dependence on plants is demonstrated by the crucial role played by plants in human biological and cultural evolution . . . by changing or biological and psychological makeup and constraining our historical modes of social organization. Humans lived first as Palaeolithic hunter-gatherers in wild nature with both their biological and cultural evolution strongly determined by factors in the natural environment. Then, as Neolithic farmers, it was cultural factors that increased in significance. Humanity had taken a giant step from a mode of existence dominated by nature to one constrained by culture as, superimposed on slow biological evolution there followed a period of rapid cultural evolution. In domesticating plants and animals, humans had adopted a sedentary way of life that changed their environments of both biological and cultural evolution. The result was modern civilization, and in this sense, humans were co-incidentally domesticated by plants. Humans whose bodies and minds were fashioned by adapting to natural wild environments, now live in artificial environments, a result of the greatly accelerated increase in social organization made possible by the energy of cereal grains and fossil fuels. This has created a new set of challenges, a new environment, for both biological evolution and cultural adaptation.
The Neolithic Agricultural Revolution (c. 12,500-2500 BP) took humanity out of wild nature – out of the nomadic hunter-gatherer natural environment of evolutionary adaptation – into artificial or ‘man-made’ farming settlements with cultivated food plants that were the products of human selection. Food energy obtained from wild plants and animal hunting was being replaced by that of domesticated cereals and livestock. Cereal grains were a form of energy that could be stored for year-round use. The surplus plant energy released by agriculture enabled rapid growth in population, division of labour, and an increase in social complexity that facilitated the creation of cities (including designed urban spaces like parks and gardens) and the many cultural activities we associate with civilization. Well-governed urban communities could then take advantage of the technologies of scale by, for example, assembling armies, constructing ocean-going ships, and building up manufacturing industries. A giant step had been taken on the path from nature to culture and from wild environments to cultivated environments as slow biological evolution was supplemented by rapid cultural evolution. All these changes flowed from the surplus energy made available by plant domestication as the human population multiplied from a few million people at the dawn of the post-Ice-Age Agricultural Revolution about 10,000 years ago, to 400 to 500 million in 1650 CE.
The Industrial Revolution (c. 1750-1850) then harnessed the concentrated plant energy in fossil fuels to power technology that would put the Agricultural Revolution into overdrive as the human population soared. It took 200,000 years for the human population to reach 1 billion around 1800: by 1914 the total was about 1.8 billion. The introduction of industrial agriculture was, in effect, a Second Agricultural Revolution creating another dramatic social transformation by releasing people from toil on the land to move from the country into the city: from farm to factory. In 1800 about 3% of the world population lived in cities but by 2017 this had increased to 54.9% (Index Mundi World Demographic Profile 2018). The associated increase in social complexity resulted in technologies and social systems that connected the peoples of the world as never before.
The Industrial Revolution was a period of greatly accelerated cultural evolution characterized by growth and expansion in many factors including: human population, industrialization, urbanization, globalization, democratization, social complexity and knowledge.
The human transition from environments and lifestyles determined by factors in nature, to environments and lifestyles determined by cultural factors, has created a new co-evolutionary relationship between humans and plants. To derive maximum benefit from our association with plants we have, in the course of the Agricultural and Industrial Revolutions, altered our relationship to plants in three major ways: we have devised ever more effective ways of harnessing plant energy, we have modified plant genetics, and we have drastically altered the geographic distribution and species composition of plants over the surface of the Earth.
Human cultural evolution has transformed both plants and their environments. But in so doing we have changed the environments that also shape our own biological and cultural evolution. Humans have domesticated plants but, since plants required the sedentary lifestyle that produced modern civilization humans have, in their turn, been domesticated by plants. Botanic gardens are appropriate institutions to monitor this ongoing plant-human interdependence and co-evolution.
All of human history, and that of all animals, is founded on the availability of plant energy. From this global context of Sun and plant, all else flows …
Gradually, through the first three phases of human existence (Natura, Agraria, Industria) six significant categories of economically important plants emerged: those used in everyday living (dyes, fibres, resins etc.), medicinal plants and spices, horticultural plantation crops, agricultural crops, forestry timbers, and the ornamental plants of horticulture (first clearly recognized in the agrarian cities of the Bronze Age). There is a further and more recent seventh category, the unintentionally introduced plants that have escaped from cultivation to naturalize in the wild across the world.