Dying is a process of time that all organisms undergo. From a biological standpoint, dying is synonymous with the concept of aging and metabolic degrading. The biological state or process of aging is known as senescence.
A phenomenon known as cellular senescence is a cell’s apparent ability to divide (reproduce via cellular division) only a limited number of times in culture, negating the concept of perpetual cell replication. This phenomenon was illustrated in 1965 by Leonard Hayflick and was called the Hayflick limit. The aging process of an organism is known as organismal senescence and is typically quantified in terms of what is called a life span. A life span is defined as a length of time that an individual organism is expected to live. In humans, a life span is typically measured in years.
Death is the permanent end of the life of an organism. The principal causes of death are typically aging-related processes that cause a decrease in, and consequently the cessation of, metabolic actions. Other causes of death could include predation, environmental changes, and decreases in the availability of food. Overall, death is the inevitable consequence of aging. Although death may be viewed as undesirable, it is actually a natural part of the cycle of life.
Several factors influence the process of dying, thus slowing down or speeding up the process. Environmental factors most notably can affect the life span of an organism. A favorable environment can provide an organism with the proper food sources and ideal living conditions for it to attain a maximum life span. An unfavorable environment with insufficient food sources and hostile conditions (such as extreme temperatures) could directly cause an organism to die much sooner than its anticipated life expectancy.
Diet, or what an organism consumes for metabolic demands, can influence the rate of dying. For example, if an organism requires proteins and sugars to survive, where and how those two things are attained could have a positive or negative effect on that organism. If this food source is hazardous to procure or contains additional hazardous chemicals, then this could possibly increase that organism’s rate of dying. However, if the food source is found in different forms that are safer to procure and/or contain less or no additional hazardous chemicals, then this would decrease that organism’s rate of dying.
What type and how many predators an organism has can also affect its life span. An organism’s ability to survive against predators depends on its genetics (inherited) and learned behavior. These two things give an organism a better chance of evading or fending off predation.
In essence the abilities of an organism to obtain food and avoid becoming food can increase its life span and prolong the dying process. These abilities would be favored by natural selection, a natural process by which favorable traits or genetics (that are inherited) become more common (by way of survival) in a population of reproducing organisms and, consequently, unfavorable traits that are also heritable become less common or eventually extinct.
Factors Affecting Human Life Expectancy
In humans, life expectancies (or the average life span of a group of organisms) have steadily increased. In the United States, the average human life expectancy was only 47 years in 1900, compared with 77 years in 2000. That is an average increase of 30 years. The global life expectancy in 2000, however, was 67 years, which is lower than in the United States and other industrialized nations but much higher than the global life expectancy in 1800, which was about 37. Five major factors are believed to have contributed to this increase in the U.S. and global life expectancies: improvements in general health, decrease in infant mortality, the advent of modern medicine, increased availability of food, and natural selection.
First and foremost is the improvement in general health, particularly the conditions of cleanliness and hygiene among large populations. In fact, one of the largest increases in life expectancies coincides with the advent of sewer systems. This greatly decreased both the spread of communicable diseases and the development of plagues that had wiped out massive numbers of people in the past.
Second, and often regarded as the most important factor in the increase of life expectancy, is the decrease in the number of infant deaths. This is more noticeable in industrialized countries, where the near elimination of infant mortality has been attained owing to improvements in prenatal health and medical obstetrics. From a mathematical standpoint, if you eliminate the number of zeros from your group of infant numbers, then the calculated results of your average life expectancy increases drastically.
Third, improvements and advancements in medicine have contributed to the prolongation of human life. For example, vaccinations against diseases like rubella, polio, and tetanus have allowed more individuals to survive beyond adolescence. In addition, improvements in diagnosing and treating diseases have also contributed to the increase in life expectancy. More interesting is that with the completion of the Human Genome Project, the physiology of aging may be better understood, and aging may perhaps be genetically halted or even reversed. This, of course, raises scientific, philosophical, and religious speculations.
Fourth, the increase in the availability of food has increased the life expectancy because of a decrease in the number of individuals dying from starvation. Just a century ago food was much scarcer and had to be grown or hunted if not bartered for. In those fragile times, if a crop failed or other unforeseen disasters took place that caused a shortage of food, people died of starvation. In modern times, hundreds of restaurants and grocery stores can be found in a single city, and in industrialized nations there is actually an overabundance of food. This could in turn have an adverse affect on life expectancy. Because of this overabundance of food, and the fact that much of this food is high in fat, cholesterol, and calories, industrialized nations like the United States are developing epidemics of obesity, diabetes, and increases in coronary artery disease. It has been postulated that in the near future we can expect to see a decrease in life expectancy for the first time in over 200 years.
Fifth, natural selection, in a theoretical way, may have improved human life expectancy, but perhaps only initially. In a given species, stronger individuals that live longer have more of an opportunity to reproduce, whereas genetically inferior members of the species die sooner and thus have less opportunity to reproduce. So initially when our species lived in more dangerous conditions, natural selection worked to improve the life expectancy, in general, by providing favorable genetics. However, there are newer philosophical speculations that have developed with regard to natural selection contributing to the improvement in life expectancy. Because our environment is not as hazardous as it once was, genetically weaker individuals are able to survive and reproduce, sometimes in large numbers. Therefore, because there are not as many natural factors to pressure the species to improve genetically, the gene pool is beginning to decrease in quality. This idea is known as “failure to improve the species” from a natural selection point of view.
Changing Views on Dying and Death
From a cultural standpoint, attitudes toward dying and death have changed over time. One major topic that has catalyzed moral and ethical thought about death and dying is euthanasia. There are two definitions of what euthanasia is. Passive euthanasia is the withdrawing or withholding of life-prolonging medical treatment, which in turn increases the rate of dying. This is typically done in what is believed or assumed to be in that patient’s best interest because of the expected decrease in the quality of his or her life as a result of a current medical condition. Active euthanasia is the intentional act to end the life of a person who would otherwise suffer from a painful or incurable medical condition. Active euthanasia is illegal in most countries, whereas passive euthanasia is gaining more acceptance. Another factor influencing the acceptance of euthanasia is the cost of keeping terminal patients alive with little or no chance of their having a normal quality of life.
Understanding and Dealing With Death
The acknowledgment of death is the realization that another individual has ceased to exist. Mourning is the grief that an individual experiences as a result of the death of someone close or special to that individual. During this experience, an individual will undergo what is known as the grief cycle. The grief cycle, as originally outlined by psychiatrist Elisabeth Kübler-Ross, consists of five stages: denial (This can’t be happening), anger (Why me?), bargaining (Please let me live to see [a particular event] happen first), depression (What is the point of going on?), and acceptance (He [or she] is in a better place now).
As we live, we witness the deaths that happen to others, but how do we come to terms with the fact that we too eventually will die? An organism’s ability to comprehend that it is dying and will at some point cease to exist is known as death consciousness. This appears to be specific only to humans. Although some animals are reported to experience grief, it is uncertain if they are conscious of the fact that they too will eventually die. An animal’s avoidance of death is driven more by instinct than by realization of a definite end.
In all likelihood, death consciousness was the driving force that motivated most religions to hypothesize the concept of the afterlife, which refers to the immaterial continuation of life or life after death once the physical processes of life have ceased. Every culture and religion has its own beliefs concerning what happens after an individual dies. For example, Christianity professes that when you die, your soul, which is immortal, goes to heaven if you were a good person or to hell if you were a bad person, based on the commandments of that religion. In many Asian philosophies or religions, it is believed that when you die, you are reincarnated into another type of life form. Other religions, such as Zoroastrianism, believe that the dead will be resurrected at the end of time. On the other hand, atheists and agnostics do not believe that there is life after death. However, all ideas about what, if anything, happens after death must remain speculative in the absence of proof or even of a universal agreement about what would constitute such proof.
Whatever religion or philosophy a person believes in, there is a general human tendency to want to remember loved ones or to be remembered after death. This is the purpose of a funeral, the ceremony that marks the death of an individual. In some cases, a monument is erected in remembrance. The burial of the dead is hardly a new concept. In fact, evidence discovered in the Shanidar Cave (in Iraq) establishes that Neanderthals buried their dead and adorned them with flowers. Some people, however, prefer not to be buried and choose to have their remains cremated instead.
The concept of eternal recurrence is a cosmological speculation based on the premise that the expanding universe has a limit, based on the current scientific assumption that there is a finite amount of matter. Once this limit is reached, it is believed that the universe may contract back to its origin, only to expand once again, then again to contract, and so on. Because the number of changes proposed through this model of expanding and contracting is believed to be infinite (which is another scientific assumption), there is a possibility that an exact state can occur an infinite number of times. In other words, this life may recur again an infinite number of times and may have already occurred an infinite number of times. In physics, an oscillatory model of the universe could illustrate and explain how the universe could cycle through the same events infinitely. Therefore the concept of eternal recurrence, from a scientific account, would be a function of energy and time. This also provides a model that death is not a permanent end.
The concept of eternal recurrence has its roots in ancient Egypt (c. 1600 BCE). The ancient Egyptian alchemy symbol, the ouroboros, which in Greek means “tail biter,” is typically represented by a snake or serpent-like creature devouring its tail to form a circle. This also represents the concept that time is cyclical as opposed to linear. The idea of eternal recurrence was revisited by the German philosopher Friedrich Nietzsche, most notably in his works The Gay Science and again in Thus Spoke Zarathustra. Philosophically, eternal recurrence is a cosmological form of life after death.
John K. Grandy
See also Birthrates, Human; Diseases, Degenerative; DNA; Eternal Recurrence; Fertility Cycle; Life Cycle; Longevity; Malthus, Thomas; Nietzsche, Freidrich
Despelder L. A., & Strickland A. L. (2005). The last dance: Encountering death and dying (7th ed.). New York: McGraw-Hill.
Galor, O., & Omer, M. (2005, October 12). Natural selection and the evolution of life expectancy (Minerva Center for Economic Growth Paper No. 02-05). Retrieved July 20, 2008, from ssrn.com/abstract=563741
Riley, J. (2001). Rising life expectancy: A global history. Cambridge, UK: Cambridge University Press.