By Alex Enescu (M.Sc. Candidate: Psychiatry Department, Faculty of Medicine).
The concept of food, as a harmless and purely nourishing substance, is — in every respect — an undistilled cultural construct. Nature produces metabolizing, reproducing, living organisms. Not food. Some of these organisms are predators. Some are prey. Some are higher up the proverbial “food” chain, while some are lower down its hierarchy. From an external point of view, fish, mammals, amphibians, plants, insects and plankton, all stand on equal evolutionary footing. Plants and plankton haven’t evolved to feed animals and fish. Nor have animals and fish evolve to feed off of other vertebrates. They have each adapted to their own individualized environment, in order to maximize their long-term survival opportunities and reproductive chances.
From an evolutionary point of view, all organisms are equal. A piece of kale, or iceberg lettuce, is just as anatomically modern as an ape, human or mussel. Not only this, but the purpose of animals, plants and microbes is similar in scope and ambitions across species i.e., to metabolize, discharge waste matter and pass down genetic material through a variety of diverse reproductive mechanisms. That’s it. Nowhere on this list does “to nourish other organisms” come into play.
Now, in the endless struggle for procreation, organisms have evolved various, interdependent, survival strategies. Most of these involve some form of metabolizing architecture, and a mechanism through which the assimilation of nutrients is made possible. Plants, for example, have evolved the ability to derive the vast majority of their daily nutritional requirements directly from the sun through photosynthesis i.e., a process through which sunlight is used to produce food directly from carbon dioxide and water. Herbivorous mammals, have evolved the ability to digest copious amounts of vegetation, and, as a consequence, have “learned” to strive on photosynthesis-plant-derived-nutrients for their own benefit. Still, other animals, such as carnivorous mammals, have evolved an array of skills, traits, and abilities (e.g., larger teeth, claws, strength, agility, various degrees of abstract thinking, a shorter digestive tract, increased stomach acidity, and so on) through which they can efficiently guzzle down herbivores, and muster their plant derived nutrients.
In all of these instances, what we are witnessing is a transference of nutrients, which originate in the photosynthesis process. As such, organisms constantly compete against each other for access to the same fundamental resources i.e., sunlight, water and minerals. While plants require minimalistic conditions to thrive and to produce nutrients, they have certainly not evolved to serve as the foodstuff of other organisms. Plants, just like animals, have evolved to optimize and increase their chances of survival.
While few organisms would go head to head with a lion, which can defend itself by virtue of its sheer size, strength, teeth, claws and ferocity, the same cannot be said about plants, shrubs and vegetation. For this reason, in order to survive, plants have equally evolved the ability to defend themselves, their laboriously “convened” nutrients, and their seeds. Otherwise, they would simply be grazed out of existence by herbivores. So, while plants may appear vulnerable —or immediately available for consumption— they, just like any large tawny-coloured savanna dwelling cat, also benefit from a multiplicity of defence mechanisms. But, instead of fangs, pincers and nippers, plants defend themselves through the production of antifeedants, toxins, and anti-nutrients.
Vegetation has been repeatedly observed to alter its toxicity levels when overgrazed. In isolated cases, trees have even been documented to “meaningfully” respond to erratic over-grazing circumstances, by altering the toxicity level of their leaves in an effort to collectively ware off predators. The way through which they achieve this is remarkably simple, and, from an anthropomorphic perspective, erringly similar to our notion of community and wilful action. When over-nibbled, Acacia trees, for example, release ethylene in their immediate surroundings. As such, nearby trees can pick up the hydrocarbon scent, and register it as a warning signal.
In response to ethylene, neighbouring Acacia trees release their own hydrocarbon phytochemicals into the atmosphere. In addition, they register the chemical signal by increasing their tannin levels—a substance which is toxic to grazing animals. While phytochemical communication may appear rudimentary in form, it is not entirely dissimilar to how other organisms, such as large mammals, exchange meaningful information with each other in order to protect themselves from predators i.e., through species-centric signalling. So, while plants may lack teeth, claws, and pincers, this does not mean that they are defenceless, benign organisms. Quite the contrary.
Aesthetically, plants and animals are about as different from each other as two things can get. Plants, for the most part, come across as harmless, unconscious and purposeless quasi-inanimate objects. Animals, on the other hand, come across as conscious, attentive and self-reflective organisms. But, this is an entirely anthropomorphic, human-centric, cultural supposition, which is not grounded in bioevolutionary facts. Indeed, while we may see ourselves in the eye of our pets, cows and chicken, we have a hard time seeing ourselves in the “eyes” of trees, shrubs and vegetation. To expand further on this example, plants don’t have immediately identifiable sense organs. Not because they are not evolutionary “sophisticated” enough to have evolved them, but because they have “chosen” a different survival strategy.
Eyes, for example, evolve in conjunction with movement. Without movement, there is no survival advantage to having vision. In fact, vision without movement would amount to little else than evolutionary cruelty i.e., being able to witness your own quietus in the absence of a viable escape mechanism. For the needs and purposes of plants, phytochemical receptors are a far more efficient mechanism when it comes to detecting detailed chemical changes in the immediate environment —an indispensable ability to posses if your survival depends on photosynthesis— than sensory input would be. As such, in contrast to vertebrates, plants have evolved, an equally “modern”, albeit, radically “alien” array of “senses”, and survival mechanisms.
Plants, trees and vegetation have developed to stay put, and, as it were, simply “hope for the best”. Instead of moving within their environment, they have evolved the ability to adapt their own internal chemistry (or inner “environment”), in order to better match external circumstances. Vertebrates, on the other hand, have taken faith into their own proverbial hands, and have lay hold of a different evolutionary route—one that involves roaming, and actively searching for “food”. In other words, cross-species anatomical differences between plants and vertebrates are reflective of contrastive survival strategies, and not of different degrees of evolutionary “development”. From an evolutionary perspective, all contemporary organisms are equally evolved.
Food, as such, is not a universal construct, it is a species relative category, which reveals genus-specific evolutionary traits, abilities and biochemical features. For this reason, there is no such thing as food in nature, just metabolizing, interdependent, organisms, and the by-products of their reproductive mechanisms e.g., grains, seeds, nuts, beans and fruits—which, just as their parents, equally benefit from the production of antifeedants, and other defence mechanisms.
To be continued…
Banner Photo by @quinntheislander // @ pixabay