The same way we have critical systems and organs in our individual biological membrane, we live in the context of a larger membrane, a larger body of life, which also has critical systems and organs. There are creatures, that if removed or diminished, can severely harm or destroy the body of life on which we depend. Large scale damage caused by relatively small changes in the body of life are called a trophic cascade.
For instance; the presence of wolves obviously changes the behavior of all the animals they prey on which affects all the biological organisms and environments they in turn interact with. If wolves are removed from system, the behaviors of the prey animals changes. Certain plants that were once off limits are now an option, others might now be ignored. The places they walk and how their reproductive drives impact the environment all begin to shift. This change in turn affects a number of other biological and physical systems. The prey animals might overpopulate. They might eradicate certain plant forms and under harvest their former food sources which can threaten or collapse their populations. The plants that depended on them to spread their seed may now be harmed. The point is, biology is an interconnected web, not a collection of isolated genetic islands.
Trophic cascades affect metabolic processes in a biological web, but they also impact social behaviors. If prey animals have less reason to be as cohesive as a herd and have less reason to run and stay fit this can change the way they relate to each other. This might impact their survivability through tough winters which depends on a certain type of sociality. They might get water from different sources changing their impact on the soil and river revetments. This can have an impact on plant life and fish etc. So extensive is the potential effect of a singular change in a biological ecosystem that it can alter the entire biological web all the way down to microorganisms. This type of collective effect in an ecosystem is called a top-down trophic cascade.
Bottom up cascades are also possible. When a primary producer in a food web is eliminated it has enormous ripples of impact up the chain. Removal of a predator, prey, or any creature from an ecosystem can cause a network of cascading consequences to the biological web. Not all of the effects are obvious. One reason these effects can be hard to detect is because many of the consequences are non linear. Some can be buried in a network of interconnections that appear as symptoms far removed from the cause. No matter the origin, this cascading impact on the balance of interdependencies present in biological systems is called a trophic cascade.
The interdependent properties of biological systems that are otherwise invisible are revealed once a trophic cascade lens is applied. If we only apply linear thought to the process of examining biological systems, we might think that whales eating fish diminishes fish stocks. We might also think that eliminating whales from the biological equation would increase fish stocks. This is not how biological systems work. The nature of the whole food web is such that what one creature produces as waste is what another needs as food. As mammals, we need oxygen to power our metabolism. Oxygen is a waste product of photosynthetic organisms. They need the carbon dioxide we produce. Together, we are part of the same body of life.
Trophic cascades are nothing new. Neither is one biological organism acting in such a way that their own survival is jeopardized. The Huronian glaciation was a world wide glaciation event lasting from 2400 million to 2100 million years ago. It was followed by, and probably caused by, the Great Oxygenation Event. This was when atmospheric oxygen began to rise dramatically due to photosynthetic cyanobacteria which appeared on earth about 200 million years prior. At the time there was no complementary life form to cycle the oxygen back into a usable form for the cyanobacteria. As a consequence they were drowning in their own waste. Once Earths oxygen sinks became saturated atmospheric oxygen increased and atmospheric methane decreased which caused a climate shift, triggering a world wide glaciation. Since free oxygen is toxic to obligate anaerobic organisms like cyanobacteria, the concentrations of oxygen are thought to have wiped out most of the Earth’s anaerobic inhabitants at the time.
This means cyanobacteria were responsible for one of the most, if not the most significant extinction events in Earth’s history, including many of them. It was not until aerobic organisms began to evolve which consume oxygen that the Earth began to recover and develop some kind of equilibrium.1 From a very wide lens, we are actually a complex form of dung beetle that consumes and repairs the oxygen by binding it with carbon for use as a metabolite for the very creatures that spawned us so long ago.
Interdependence is the principle of sustained structures in biological systems, and these chains of interdependency have developed complexity over the millennium. The Gaia hypothesis, also known as Gaia theory or Gaia principle, posits that organisms collectively interact with their inorganic surroundings on Earth to form a self-regulating system. Together the biological systems help maintain the metabolism of the planet, such that it supports sustained life on the planet. This speaks to the common role of every biologicla creature, and to what can happen if a particular species falls out of harmony with that role.
The same way our individual bodies have critical organs and critical relationships with other organisms that we depend on. Earth itself has a metabolism that we need to cultivate and tend to in order for us to continue. We are a voice in the choir of life. Any creature that falls out of harmony with serving a nourishing role in the body of life has faded from the biological landscape. Sometimes this exit is dramatic and sometimes a lot of splash damage is caused by the chaos of the exit.
Recognizing that not only we, but the other creatures we share this Earth with are part of our collective body of life is part of the cultural paradigm shift that must take place in order for us to sustainably move forward into the future. If we recognize the value of nourishing each other, and the body of life, we also maximize our chances for a fulfilling future. We know that desert environments are full of spines and reflect the harsh realities of their environment. The same way we know the lush fruits of the tropics provide plentiful nourishment sources. The difference is the environment and we have the capacity to cultivate the environment. The real question is will we squander or leverage this capacity to serve the body of life, and by extension ourselves?
1Prokaryotes such as cyanobacteria which are thought to have produced atmospheric oxygen.