Death, a biologist’s view
The elements, the quantum structures that construct these elements and the dark energies that bathe them are ubiquitous in our vast universe. They are the basis for the existence of matter and are the “building blocks” of physical existence as we know it. Given specific parameters of light, liquid water, heat, time, and substrate composed of the elements, life, the ability of organic molecules to self replicate, can develop. And life is dynamic, to exist it must grow and change, it must feed upon itself, be capable of changing as its environment changes and be complicit with creating change to enhance survival of the many and varied complex forms that interact to follow the many evolutionary paths that lead to survival. Survival of a species of plant or animal cannot happen without a reproductive scheme that shuffles the genome that directs development of the individual life forms that compose the species. This plasticity of the gene pool that composes a species provides the species with the capacity for change and environmental adaptation that allows the species to survive and adapt to environmental and ecological change. And death of individuals is essential for the mechanism for developmental change that allows survival of the species to be effective. Death of the individual is a biological imperative for all sexually reproducing species to compete and persist in an ever changing environment.
Plants and animals, save one, do not know death. They experience death and for the most part, they instinctively avoid death, accepting it only when it is inevitable, but they do not intellectually know or understand that their own death is inevitable, Many animals, primarily carnivores and omnivores, create death of other animals in their instinctive quest for food and reproduction. The delicate balance between birth, death, reproduction strategy, seasonality, food availability, and genetic lability that determines the survival of all species is a vast web of life termed ecology. We are the only species on our planet that has developed an interactive, conspecific intelligence and the technology that allows us to rise above, and actually modify natural ecology to enhance the survival of individuals and the gene pool that is our species. This knowledge of the meaning and existence of death and our evolved traits of compassion and dependence upon tribal social structure essential for survival of our species has given us a great understanding and fear of the individual and collective loss that occurs with the deaths of individual humans. Death has become an adversary to be battled on every front. And every day, through science, medicine, and environmental engineering, we battle valiantly against individual and communal death. Sometimes, very often, our battles for natural resources, domination, and against impending violent death, results in the death of great numbers of our conspecifics in war and pogrom, actions designed to ultimately enhance the survival of our own genetic or political subset of the human genome.
Death is a biological necessity for survival of the gene pools that compose a species. Sometimes individual death is part and parcel of species survival strategies beyond simple reproduction. The entire reproductive strategy of the species depends on the death of the individual. Two examples that come to mind are the death of the male preying mantis during copulation with the female, she eats him as he is in performance of his reproductive duty, and the male of the deep-sea Ceratoid sea angler fish, who gives up his individual existence by attaching to the female by biting into her epidermis, fusing blood circulation, degenerating and becoming nothing more than a male reproductive organ attached to her body. Many species have evolved physical and behavioral characteristics that demand great individual sacrifice, often death in competition for reproductive opportunity, to assure reproductive success and enhance survival of the species. Reproduction and death are the corner stones of species survival and evolutionary change.
Many animals also take the lives of other animals to sustain their own life, they are know as carnivores, species that physically consume the life energy of other animals, usually herbivores, to sustain their own life. Omnivores feed on both plant and animal life. There is, however, only one animal that has the capacity to know and understand the meaning and finality of individual death and sometimes if the occasion demands, will knowingly sacrifice their own life for that of their offspring and/or their society. This species, Homo sapiens, will also occasionally for various reasons, with full knowledge of the results of their action, take their own life because of mental and social problems and disorders. This self destruction of life is knowingly undertaken only by the sentient species that can dominate and control the environment and life itself. Also, although it is a very complex physical, mental, and social phenomenon, it could be argued that an increasing unusual practice within human cultures of physically, mentally, and socially changing ones genetic, biological, and social identity from one sex to the opposite sex despite morphological sexual development is in essence, the individuals taking of one life for the substitution of another life. Admittedly this is a stretch, but in actuality, one individual ceases to exist and another individual claims that existence.
One may not think that death is imperative to survival of the individual, and obviously it is not. Ever since the development of abstract thinking, humans have known death to be the end of biological life, but many (most) have and still do, consider death as a physical ending that is not necessarily the final ending that God(s) intend for human beings; and through an anticipated supernatural intervention, an existence beyond the physical, good or bad, that might occur, might not occur, or that could, would, occur, or that might even be given and then rescinded. Humans have developed many and varied scenarios on such possibilities. But biological death of individuals of basically every multicellular species is imperative in the same sense that reproduction is imperative, not for survival of the individual, but for survival of the species. The common religious explanation for death, that God banished Adam and Eve from the Garden of Eden, and sentenced them to die (eventually) for eating from the Tree of Knowledge, is at best a poor analogy for human evolution, and at worst, just an ancient fictional explanation of the supernatural capriciousness of a fictional god.