Coevolution

Coevolution is a powerful expression of biological agency, the purposiveness or directedness that uniquely defines life as each species in the relationship derives benefit from the other as expressed in the biological axiom – the universal, objective, and ultimate predisposition of all organisms to survive, reproduce, and flourish.

In a coevolutionary relationship each party exerts selective pressures on the other, thereby affecting the other’s evolution. A popular example is the way that plants and their insect pollinators underwent reciprocal physical change as a result of their interaction; the way some orchid flowers, for example, mimic the forms of insects in order to attract pollinators or the way that selective pressures can drive an evolutionary arms race between two species. The evolution of plants and humans is a parallel reciprocal interaction.  The interaction of plants and humans was one in which the global reduction in plant diversity has resulted in human advantage.

Biological and cultural evolution are two crucially different kinds of evolution that need further explanation.

Biological evolution

Biological evolution can be defined as descent with modification as a result of heritable variation and differential reproduction among replicating individuals. This is a mechanical process of fine-tuning using feedback. It also a slow process involving the incremental adaptation of organisms to their environments that takes place as a result of mostly small biological changes that take place over millennia

The coevolution of plants and people has resulted in reciprocal biological change as humans domesticating plants have altered plant genetics to their own ends, first by selection, then by ever more sophisticated and penetrating genetic manipulation. Conversely, human dependence on plants, especially as food, has influenced the evolution of human senses and the digestive system.

Photosynthesis first occurred about 3.5 billion years ago but the seed plants we are most familiar with evolved much later – conifers over 300 million years ago, and flowering plants about 125 million years ago. On the human animal side mammals date back about 200 million years, the great apes about 14 million years, the genus Homo about 2 million years and our species, Homo sapiens, about 200,000 years.

Unsurprisingly, since plants have always been a major part of the human environment of evolutionary adaptation (EEA), there are many physical and psychological traits that we can attribute to plants. These are discussed in the article Plants make sense). Simply by being living organisms there are many vary similar biochemical pathways held in common. However, the specific innate human traits that have been related to evolutionary plant influences include: bipedalism, stereoscopic and colour vision, dentition, the digestive system, taste (sweet and sour), the biology of smell, and lactose tolerance.

universal (innate) human biological traits including: bipedalism, colour vision etc. (see Plants make sense). In contrast humans have, for most of the evolutionary history of plants, had little impact on plant biology, partly because of the relatively brief period of plant evolutionary history that has been occupied by humans and partly because of the small human populations that existed over the relatively brief evolutionary period that they have existed together. Human influence on plants has all been recent, beginning with the use of fire and interference with natural trophic cascades. By far the greatest human impact on plants has occurred in the last few hundred years as human social organization has become vastly more integrated and complex. Though there was a little genetic alteration, by selection over several millennia, and some geographic dispersal of crop plants this was minor compared with contemporary plant breeding, genetic engineering and Cultivated plant globalization of recent times.

Plants, then, are not just ‘useful’ to humans, they have been the source of major human biological and social transformation.

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Humans co-evolved with plants this strongly affecting our senses of taste, smell, digestive system and dentition, our emotional response to our surroundings, and possibly the initiating factor for the fact that we are bipedal and have colour vision. This is discussed further in the article Plants make sense
The following is a personal interpretation of the most significant historical factors.

We know that small changes at the beginning of a evolutionary process can have momentous long-term impacts. The following key transitions provide examples of this general historical principle.

The relationship between plants and people is one of coevolution.  Plants have influenced the evolution of the human sensory, digestive, and other organs (see plants make sense), while humans have modified plant genetics in the manufacture man-made or anthropogenic plants (cultigens).

Articles on biological coevolution examine the way plants have influenced our human biology (see plants make sense) and the way plants share with us their biological agency (see plant sense and life as agency).  Cultural evolution is examined through the lens of traditional historical factors such as social organization, technology, population growth and how humans have changed the distribution, specie composition, biomass, and genetics of plants. Using a scientific approach it employs a systematization of ideas that will stand the test of time by providing a foundation for future research. This is addressed in the article on plant classification.

In the course of the dialectic of human-environment adaptation selection pressure came first from nature (geography) and subsequently from culture (people and institutions).
Morris’s long-term temporal scale draws our attention to spatial scale as geography: small village settlements became towns, cities, city states and empires based around resources, mostly energy, firstly local but subsequently based around river valleys, then oceans. Energy and geography were the key determinants of where and when things happened over the long term. The question of why they happened at all is more a biological question about human nature.
Morris is modest about the role of historians. If we want to know why history is the way it is we need to look to biology – to human human nature; if we want to know how it works we need to look to sociology; and if we need to know where certain changes are likely to have occurred in the past then we should look to geography.
Geography, he argues, accounted for the origin of agriculture in the ‘lucky latitudes’ where there were plants and animals that could be domesticated in the amenable bioclimatic conditions that arose in these regions after the last Ice Age.

Cultural evolution