The coevolution of plants and people has resulted in reciprocal biological change as humans domesticating plants have have altered plant genetics to their own ends, first by selection, then by ever more sophisticated and penetrating genetic manipulation. Conversely, human depemdence 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.
But let’s begin with their utility.