Sunday, July 28, 2019

Parasites And Symbionts

                                                                                                  written 14 July 2019
                                                                                              published 28 July 2019

            In the first Matrix movie, one of the agents refers to humans as a disease: a parasite infecting the planet.  High altitude pictures of cities show an extensive grey zone of concrete that looks dead.  Dead zones occur in all the oceans where excessive agriculture nutrients promote alga blooms which die, decay, and remove all the oxygen.  Plastic trash gyres occur all over the planet, killing life with indigestible material.  We are in the middle of the sixth extinction, this one man made.  The planet is heating faster every decade, threatening extinction of all life.  It is easy to see that the Matrix agent might be right.
            A parasite is a life form that lives in or on another organism, competitively taking energy and nutrients at the expense of the host.  Because the energy flows only one way, aggressive parasitic growth can eventually cause the host to die.  Such parasites survive only if they can procreate to another host in time. Sometimes the parasite learns to moderate its growth so that the host is not too weakened, allowing both to survive longer.  Some parasites move through several different host species during their life cycle, including hosts that are completely unaffected, and only move the parasite to a new location. 
            Another life strategy is symbiosis, a cooperative model where the energy and nutrient exchange flows both ways, or the symbiont provides essential services to the host organism in exchange for support.  All life developed first as individuals, but over time, found that cooperation increased everyone's survival rate.  Some symbiotic forms are between autonomous individuals, such as cattle and tick birds, dogs and humans, and gut bacteria and humans.
            But others symbiotic forms actually merge, losing autonomy, such as eukaryotic cells, where the genetic material for all the parts of previously autonomous non-nucleated cells has been collected into the nucleus.  All higher organisms have nucleated cells.  In the human body, almost all cells have hundreds or even thousands of autonomous cells called mitochondria, within the cell membrane.  Mitochondria produce the energy molecule used by the rest of the cell, and in exchange, the cell protects and feeds the mitochondria, which can no longer survive on its own.
            Humans are a relatively young species, and the evolution of self-consciousness is even more recent, but there can be little doubt that we have an impact on our host, the planet Earth.  From very modest beginnings, humans have spread across the globe, changing the environment to suit our needs.  Tool making, fire, and hunting accelerated the extinction of many animal species, and the rise of agriculture preferentially supported a very few crops at the expense of many others.  Irrigation allowed larger civilizations, but salt poisoned the land over time.  As increased farming felled the forests, which sequester carbon, the atmospheric CO2 content rose even before fossil fuels. The Black Plague killed so many peasant farmers, the regrowth of the forests caused a measurable dip in the CO2 record.
            A few centuries ago, the philosophy of materialism and the industrial revolution amplified our impact on the world.  The world was no longer sacred.  Humans weren't stewards.  Powered by fossil fuels, everything was just raw material waiting to be exploited. Human population exploded, tripling in just my lifetime.
            This is an unsustainable situation, leading to human extinction, if not in our lifetime, certainly in our children's.  We play the role of an aggressive parasite, but without the long-term game plan of a successful parasite, which must transfer to another host before the first one dies.  A quick survey of the solar system shows there is "no place like home". While several "earth like" planets have been identified within a few lightyears, we have no way to get there.
            Short of painful extinction, our only hope is to learn how to shift from an aggressive parasite to intentionally cooperative symbiont.  We have to get over our human narcissism and exclusive gain, listen to what the planet needs, and begin to live in harmony with our host, rather than trying to dominate it.  Nothing less will do.  All the indigenous cultures have survived for thousands of years, so it is within human capacity.  The only missing ingredient is a global will to survive.