Greenfield, Mass. (Special to Informed Comment; Feature) — From the largest to the smallest and the oldest to the youngest creatures on Earth — Antarctic blue whales and coastal redwoods, tiny bacteria and humans — we are all enmeshed in many different relationships. We need each other, some more than others. Plants evolved hundreds of millions of years before the first humans and — through their creativity to survive predators — transformed the Earth into a livable environment for all animals, including humans. We needed plants for our evolution and now need them to survive a climate catastrophe. They, on the other hand, did not need us for their existence and would survive without us.
To place humans at the top of the evolutionary chain as the crown of intelligent life is, as some well understand, a mistake. The dire consequences of this simple hierarchy are everywhere: a climate out of control, an ever-accelerating extinction of animals and plants, dead zones in the oceans and mass extinction of coral reefs, the enormous pollution of land, air and water, and the increasing likelihood of the extinction of humanity by nuclear war. All of these are the work of humans, and of humans with financial and political power, and they are doing so in a far worse way than others.
Certain scientists who study plants – from the simplest to the most exotic – cause controversy with their “Are plants intelligent??” Consider that we humans owe our existence to plants that provide us with food, medicine, and the critical 21% oxygen level in the air we breathe. If our human intelligence has recognized over thousands of years which plants are edible, nutritious, and healing, then wouldn’t the evolutionary ingenuity of the plants that feed and sustain us and all life also be intelligence?
“Plant Intelligence”, Digital, Dream / Dreamland v. 3, 2024
Studies have shown that elephants recognize themselves in mirrors, crows make tools, dolphins show empathy and playfulness, and cats have attachment styles similar to human infants. The explanation for this is that they have brains with neurological capacity for consciousness and intelligence.
Plants, however, do not have a central brain. Could their way of learning, avoiding insect predators and maximizing their growth rely on a diverse form of intelligence, perhaps distributed throughout their roots, stems and leaves? Could the whole plant then function as a brain? Recent studies of plants have raised the possibility that they are conscious and intelligent. Take communication, something that we humans claim as our domain through language and that we have recently begun to recognize in animals as well.
Botanists have found that not only do alders and willows change their leaf chemistry to defend themselves against an invasion of processionary caterpillars, but the leaves of distant trees also change their chemical composition in a similar way. They are warned by airborne plant chemicals emitted by the trees originally attacked. Goldenrods signal an attack by a predator through powerful chemical signals that they send to all other goldenrod neighbors, just as humans warn their neighbors of a nearby fire, flood, or crime.
Plants don’t have discernible ears, but they do detect sound. The vibration of a predatory insect chewing on its leaves causes a plant to produce its own defensive pesticide. The sea primrose responds to the sound of flying honeybees by making its nectar sweeter to attract them for pollination. Tree roots grow toward the sound of running water, including in pipes, where the roots often break through, causing great difficulties for communities. How do different plants hear these stimulating sounds?
Plants have a memory. Some plants know from experience when a pollinator will come to pollen the plant. Plants display social intelligence: Members of the legume family form relationships with bacteria that live in their roots so that those bacteria can provide plants with nitrogen that is useful for their growth. Several plant species provide homes and food for compatible ants, which then attack the plants’ ant infestation. You may have noticed that asters and goldenrods often grow together in late summer. Why? Together—their shared beauty—attracts more pollinators.
Finally, I would like to express my great respect for the indigenous worldview in which wind, stones, air and rain, together with plants and other animals, are our relatives. We humans, the youngest living creatures, are dependent on all these older relatives; and this awareness, this worldview of the interconnectedness of all living things, is our way back to the well-being of the Earth.
Featured Image, “Web of Intelligent Life”, Digital, Dream / Realistic v. 2, 2024
