Death

Death

Overview
Death is the permanent termination of the biological functions that sustain a living
Life
Life is a characteristic that distinguishes objects that have signaling and self-sustaining processes from those that do not, either because such functions have ceased , or else because they lack such functions and are classified as inanimate...

 organism
Organism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...

. Phenomena which commonly bring about death include old age, predation
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...

, malnutrition
Malnutrition
Malnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions....

, disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...

, and accident
Accident
An accident or mishap is an unforeseen and unplanned event or circumstance, often with lack of intention or necessity. It implies a generally negative outcome which may have been avoided or prevented had circumstances leading up to the accident been recognized, and acted upon, prior to its...

s or trauma resulting in terminal injury.

The nature of death has been for millennia a central concern of the world's religious traditions and of philosophical enquiry
Philosophy
Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...

, and belief in some kind of afterlife
Afterlife
The afterlife is the belief that a part of, or essence of, or soul of an individual, which carries with it and confers personal identity, survives the death of the body of this world and this lifetime, by natural or supernatural means, in contrast to the belief in eternal...

 or rebirth
Reincarnation
Reincarnation best describes the concept where the soul or spirit, after the death of the body, is believed to return to live in a new human body, or, in some traditions, either as a human being, animal or plant...

 has been a central aspect of religious faith.

The word death comes from Old English deað, which in turn comes from Proto-Germanic *dauþaz (reconstructed by etymological analysis).
Discussion
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Recent Discussions
Quotations

Men fear death, as children fear to go in the dark; and as that natural fear in children is increased with tales, so is the other.

Francis Bacon, Essays, 2, ‘Of Death’

We all labour against our own cure; for death is the cure of all disease.

Thomas Browne, Religio Medici, II. 9.

What argufies pride and ambition? Soon or late death will take us in tow: Each bullet has got its commission, And when our time's come we must go.

Charles Dibdin, Each Bullet has its Commission

Verse, Fame and beauty are intense indeed, But Death intenser – Death is life's high mead.

John Keats, Sonnet: Why did I laugh to-night?

Death opens unknown doors. It is most grand to die.

John Masefield, Pompey the Great, i.

Death hath a thousand doors to let out life: I shall find one.

Philip Massinger, A Very Woman, V. iv.

Death did not come to my mother Like an old friend. She was a mother, and she must Conceive him. Up and down the bed she fought crying Help me, but death Was a slow child Heavy.

Josephine Miles, "Conception" (1974) st. 1–2; Collected Poems, University of Illinois Press, 1983
Encyclopedia
Death is the permanent termination of the biological functions that sustain a living
Life
Life is a characteristic that distinguishes objects that have signaling and self-sustaining processes from those that do not, either because such functions have ceased , or else because they lack such functions and are classified as inanimate...

 organism
Organism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...

. Phenomena which commonly bring about death include old age, predation
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...

, malnutrition
Malnutrition
Malnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions....

, disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...

, and accident
Accident
An accident or mishap is an unforeseen and unplanned event or circumstance, often with lack of intention or necessity. It implies a generally negative outcome which may have been avoided or prevented had circumstances leading up to the accident been recognized, and acted upon, prior to its...

s or trauma resulting in terminal injury.

The nature of death has been for millennia a central concern of the world's religious traditions and of philosophical enquiry
Philosophy
Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...

, and belief in some kind of afterlife
Afterlife
The afterlife is the belief that a part of, or essence of, or soul of an individual, which carries with it and confers personal identity, survives the death of the body of this world and this lifetime, by natural or supernatural means, in contrast to the belief in eternal...

 or rebirth
Reincarnation
Reincarnation best describes the concept where the soul or spirit, after the death of the body, is believed to return to live in a new human body, or, in some traditions, either as a human being, animal or plant...

 has been a central aspect of religious faith.

Etymology


The word death comes from Old English deað, which in turn comes from Proto-Germanic *dauþaz (reconstructed by etymological analysis). This comes from the Proto-Indo-European stem *dheu- meaning the 'Process, act, condition of dying'.

Senescence


Almost all animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

s who survive external hazards to their biological functioning eventually die from senescence
Senescence
Senescence or biological aging is the change in the biology of an organism as it ages after its maturity. Such changes range from those affecting its cells and their function to those affecting the whole organism...

. The only known exception is the jellyfish Turritopsis nutricula
Turritopsis nutricula
Turritopsis nutricula, the immortal jellyfish, is a hydrozoan whose medusa, or jellyfish, form can revert to the polyp stage after becoming sexually mature. It is the only known case of a metazoan capable of reverting completely to a sexually immature, colonial stage after having reached sexual...

, thought to be, in effect, immortal
Biological immortality
Biological immortality refers to a stable rate of mortality as a function of chronological age. Some individual cells and entire organisms in some species achieve this state either throughout their existence or after living long enough. This requires that death occur from injury or disease rather...

. Unnatural causes of death include suicide
Suicide
Suicide is the act of intentionally causing one's own death. Suicide is often committed out of despair or attributed to some underlying mental disorder, such as depression, bipolar disorder, schizophrenia, alcoholism, or drug abuse...

 and homicide
Homicide
Homicide refers to the act of a human killing another human. Murder, for example, is a type of homicide. It can also describe a person who has committed such an act, though this use is rare in modern English...

. From all causes, roughly 150,000 people die around the world each day.

Physiological death is now seen as a process, more than an event: conditions once considered indicative of death are now reversible. Where in the process a dividing line is drawn between life and death depends on factors beyond the presence or absence of vital signs
Vital signs
Vital signs are measures of various physiological statistics, often taken by health professionals, in order to assess the most basic body functions. Vital signs are an essential part of a case presentation. The act of taking vital signs normally entails recording body temperature, pulse rate ,...

. In general, clinical death
Clinical death
Clinical death is the medical term for cessation of blood circulation and breathing, the two necessary criteria to sustain life. It occurs when the heart stops beating in a regular rhythm, a condition called cardiac arrest. The term is also sometimes used in resuscitation research.Stopped blood...

 is neither necessary nor sufficient for a determination of legal death
Legal death
Legal death is a legal pronouncement by a qualified person that further medical care is not appropriate and that a patient should be considered dead under the law. The specific criteria used to pronounce legal death are variable and often depend on certain circumstances in order to pronounce a...

. A patient with working heart
Human heart
The human heart is a muscular organ that provides a continuous blood circulation through the cardiac cycle and is one of the most vital organs in the human body...

 and lung
Human lung
The human lungs are the organs of respiration in humans. Humans have two lungs, with the left being divided into two lobes and the right into three lobes. Together, the lungs contain approximately of airways and 300 to 500 million alveoli, having a total surface area of about in...

s determined to be brain dead
Brain death
Brain death is the irreversible end of all brain activity due to total necrosis of the cerebral neurons following loss of brain oxygenation. It should not be confused with a persistent vegetative state...

 can be pronounced legally dead without clinical death occurring. Paradoxically, as scientific knowledge
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...

 and medicine
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....

 advance, a precise medical definition of death becomes more problematic.

Symptoms of death


Signs of death or strong indications that an animal is no longer alive are:
  • Cessation of breathing
  • Cardiac arrest
    Cardiac arrest
    Cardiac arrest, is the cessation of normal circulation of the blood due to failure of the heart to contract effectively...

     (No pulse
    Heart rate
    Heart rate is the number of heartbeats per unit of time, typically expressed as beats per minute . Heart rate can vary as the body's need to absorb oxygen and excrete carbon dioxide changes, such as during exercise or sleep....

    )
  • Pallor mortis
    Pallor mortis
    Pallor mortis is a postmortem paleness which happens in those with light skin almost instantly because of a lack of capillary circulation throughout the body...

    , paleness which happens in the 15–120 minutes after death
  • Livor mortis
    Livor mortis
    Livor mortis , postmortem lividity , or hypostasis is one of the signs of death...

    , a settling of the blood in the lower (dependent) portion of the body
  • Algor mortis
    Algor mortis
    Algor mortis is the reduction in body temperature following death. This is generally a steady decline until matching ambient temperature, although external factors can have a significant influence....

    , the reduction in body temperature following death. This is generally a steady decline until matching ambient temperature
  • Rigor mortis
    Rigor mortis
    Rigor mortis is one of the recognizable signs of death that is caused by a chemical change in the muscles after death, causing the limbs of the corpse to become stiff and difficult to move or manipulate...

    , the limbs of the corpse become stiff (Latin rigor) and difficult to move or manipulate
  • Decomposition
    Decomposition
    Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...

    , the reduction into simpler forms of matter, accompanied by a strong, unpleasant odor.

Problems of definition



The concept of death is a key to human understanding of the phenomenon. There are many scientific approaches to the concept. For example, brain death
Brain death
Brain death is the irreversible end of all brain activity due to total necrosis of the cerebral neurons following loss of brain oxygenation. It should not be confused with a persistent vegetative state...

, as practiced in medical science, defines death as a point in time at which brain activity ceases. One of the challenges in defining death is in distinguishing it from life
Life
Life is a characteristic that distinguishes objects that have signaling and self-sustaining processes from those that do not, either because such functions have ceased , or else because they lack such functions and are classified as inanimate...

. As a point in time, death would seem to refer to the moment at which life ends. However, determining when death has occurred requires drawing precise conceptual boundaries between life and death. This is problematic because there is little consensus over how to define life. It is possible to define life in terms of consciousness. When consciousness ceases, a living organism can be said to have died. One of the notable flaws in this approach, however, is that there are many organisms which are alive but probably not conscious (for example, single-celled organisms). Another problem with this approach is in defining consciousness, which has many different definitions given by modern scientists, psychologists and philosophers. This general problem of defining death applies to the particular challenge of defining death in the context of medicine.

Other definitions for death focus on the character of cessation of something. In this context "death" describes merely the state where something has ceased, for example, life. Thus, the definition of "life" simultaneously defines death.

Historically, attempts to define the exact moment of a human's death have been problematic. Death was once defined as the cessation of heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

beat (cardiac arrest
Cardiac arrest
Cardiac arrest, is the cessation of normal circulation of the blood due to failure of the heart to contract effectively...

) and of breathing, but the development of CPR
Cardiopulmonary resuscitation
Cardiopulmonary resuscitation is an emergency procedure which is performed in an effort to manually preserve intact brain function until further measures are taken to restore spontaneous blood circulation and breathing in a person in cardiac arrest. It is indicated in those who are unresponsive...

 and prompt defibrillation have rendered that definition inadequate because breathing and heartbeat can sometimes be restarted. Events which were causally
Causality
Causality is the relationship between an event and a second event , where the second event is understood as a consequence of the first....

 linked to death in the past no longer kill in all circumstances; without a functioning heart or lungs, life can sometimes be sustained with a combination of life support
Life support
Life support, in medicine is a broad term that applies to any therapy used to sustain a patient's life while they are critically ill or injured. There are many therapies and techniques that may be used by clinicians to achieve the goal of sustaining life...

 devices, organ transplants and artificial pacemaker
Artificial pacemaker
A pacemaker is a medical device that uses electrical impulses, delivered by electrodes contacting the heart muscles, to regulate the beating of the heart...

s.

Today, where a definition of the moment of death is required, doctors and coroners usually turn to "brain death
Brain death
Brain death is the irreversible end of all brain activity due to total necrosis of the cerebral neurons following loss of brain oxygenation. It should not be confused with a persistent vegetative state...

" or "biological death" to define a person as being clinically dead; people are considered dead when the electrical activity in their brain ceases. It is presumed that an end of electrical activity indicates the end of consciousness
Consciousness
Consciousness is a term that refers to the relationship between the mind and the world with which it interacts. It has been defined as: subjectivity, awareness, the ability to experience or to feel, wakefulness, having a sense of selfhood, and the executive control system of the mind...

. However, suspension of consciousness must be permanent, and not transient, as occurs during certain sleep stages, and especially a coma
Coma
In medicine, a coma is a state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...

. In the case of sleep, EEGs
Electroencephalography
Electroencephalography is the recording of electrical activity along the scalp. EEG measures voltage fluctuations resulting from ionic current flows within the neurons of the brain...

 can easily tell the difference.

However, the category of "brain death" is seen by some scholars to be problematic. For instance, Dr. Franklin Miller, senior faculty member at the Department of Bioethics, National Institutes of Health, notes: "By the late 1990s, however, the equation of brain death with death of the human being was increasingly challenged by scholars, based on evidence regarding the array of biological functioning displayed by patients correctly diagnosed as having this condition who were maintained on mechanical ventilation for substantial periods of time. These patients maintained the ability to sustain circulation and respiration, control temperature, excrete wastes, heal wounds, fight infections and, most dramatically, to gestate fetuses (in the case of pregnant "brain-dead" women)."

Those people maintaining that only the neo-cortex of the brain is necessary for consciousness sometimes argue that only electrical activity should be considered when defining death. Eventually it is possible that the criterion for death will be the permanent and irreversible loss of cognitive
Cognition
In science, cognition refers to mental processes. These processes include attention, remembering, producing and understanding language, solving problems, and making decisions. Cognition is studied in various disciplines such as psychology, philosophy, linguistics, and computer science...

 function, as evidenced by the death of the cerebral cortex
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...

. All hope of recovering human thought and personality
Personality psychology
Personality psychology is a branch of psychology that studies personality and individual differences. Its areas of focus include:* Constructing a coherent picture of the individual and his or her major psychological processes...

 is then gone given current and foreseeable medical technology. However, at present, in most places the more conservative definition of death – irreversible cessation of electrical activity in the whole brain, as opposed to just in the neo-cortex – has been adopted (for example the Uniform Determination Of Death Act
Uniform Determination of Death Act
The Uniform Determination of Death Act is a draft state law that was approved for the United States in 1981 by the National Conference of Commissioners on Uniform State Laws, in cooperation with the American Medical Association, the American Bar Association, and the President's Commission on...

 in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

). In 2005, the Terri Schiavo case
Terri Schiavo case
The Terri Schiavo case was a legal battle in the United States between the legal guardians and the parents of Teresa Marie "Terri" Schiavo that lasted from 1998 to 2005...

 brought the question of brain death and artificial sustenance to the front of American politics
Politics of the United States
The United States is a federal constitutional republic, in which the President of the United States , Congress, and judiciary share powers reserved to the national government, and the federal government shares sovereignty with the state governments.The executive branch is headed by the President...

.

Even by whole-brain criteria, the determination of brain death can be complicated. EEGs can detect spurious electrical impulses, while certain drugs
DRUGS
Destroy Rebuild Until God Shows are an American post-hardcore band formed in 2010. They released their debut self-titled album on February 22, 2011.- Formation :...

, hypoglycemia
Hypoglycemia
Hypoglycemia or hypoglycæmia is the medical term for a state produced by a lower than normal level of blood glucose. The term literally means "under-sweet blood"...

, hypoxia
Hypoxia (medical)
Hypoxia, or hypoxiation, is a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise...

, or hypothermia
Hypothermia
Hypothermia is a condition in which core temperature drops below the required temperature for normal metabolism and body functions which is defined as . Body temperature is usually maintained near a constant level of through biologic homeostasis or thermoregulation...

 can suppress or even stop brain activity on a temporary basis. Because of this, hospitals have protocols for determining brain death involving EEGs at widely separated intervals under defined conditions.

In certain cultures, death is more of a process than a single event. It implies a slow shift from one spiritual state to another.

Legal




In the United States, a person is dead by law if a Statement of Death or Death certificate
Death certificate
The phrase death certificate can describe either a document issued by a medical practitioner certifying the deceased state of a person or popularly to a document issued by a person such as a registrar of vital statistics that declares the date, location and cause of a person's death as later...

 is approved by a licensed medical practitioner. Various legal consequences follow death, including the removal from the person of what in legal terminology is called personhood.

The possession of brain activities, or capability to resume brain activity, is a necessary condition
Necessary and sufficient conditions
In logic, the words necessity and sufficiency refer to the implicational relationships between statements. The assertion that one statement is a necessary and sufficient condition of another means that the former statement is true if and only if the latter is true.-Definitions:A necessary condition...

 to legal personhood in the United States. "It appears that once brain death has been determined ... no criminal or civil liability will result from disconnecting the life-support devices." (Dority v. Superior Court of San Bernardino County
San Bernardino County, California
San Bernardino County is a county in the U.S. state of California. As of the 2010 census, the population was 2,035,210, up from 1,709,434 as of the 2000 census...

, 193 Cal.Rptr. 288, 291 (1983))

Misdiagnosed



There are many anecdotal references to people being declared dead by physicians and then "coming back to life", sometimes days later in their own coffin, or when embalming
Embalming
Embalming, in most modern cultures, is the art and science of temporarily preserving human remains to forestall decomposition and to make them suitable for public display at a funeral. The three goals of embalming are thus sanitization, presentation and preservation of a corpse to achieve this...

 procedures are about to begin. From the mid-18th century onwards, there was an upsurge in the public's fear of being mistakenly buried alive, and much debate about the uncertainty of the signs of death. Various suggestions were made to test for signs of life before burial
Burial
Burial is the act of placing a person or object into the ground. This is accomplished by excavating a pit or trench, placing an object in it, and covering it over.-History:...

, ranging from pouring vinegar and pepper into the corpse's mouth to applying red hot pokers to the feet or into the rectum
Rectum
The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...

. Writing in 1895, the physician J.C. Ouseley claimed that as many as 2,700 people were buried prematurely each year in England and Wales, although others estimated the figure to be closer to 800.

In cases of electric shock
Electric shock
Electric Shock of a body with any source of electricity that causes a sufficient current through the skin, muscles or hair. Typically, the expression is used to denote an unwanted exposure to electricity, hence the effects are considered undesirable....

, cardiopulmonary resuscitation
Cardiopulmonary resuscitation
Cardiopulmonary resuscitation is an emergency procedure which is performed in an effort to manually preserve intact brain function until further measures are taken to restore spontaneous blood circulation and breathing in a person in cardiac arrest. It is indicated in those who are unresponsive...

 (CPR) for an hour or longer can allow stunned nerve
Nerve
A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...

s to recover, allowing an apparently dead person to survive. People found unconscious under icy water may survive if their faces are kept continuously cold until they arrive at an emergency room
Emergency department
An emergency department , also known as accident & emergency , emergency room , emergency ward , or casualty department is a medical treatment facility specialising in acute care of patients who present without prior appointment, either by their own means or by ambulance...

. This "diving response", in which metabolic activity
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...

 and oxygen requirements are minimal, is something humans share with cetacea
Cetacea
The order Cetacea includes the marine mammals commonly known as whales, dolphins, and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal", was more general. It comes from Ancient Greek , meaning "whale" or "any huge fish or sea...

ns called the mammalian diving reflex
Mammalian diving reflex
The mammalian diving reflex is a reflex in mammals which optimizes respiration to allow staying underwater for extended periods of time. It is exhibited strongly in aquatic mammals , but exists in a weaker version in other mammals, including humans. Diving birds, such as penguins, have a similar...

.

As medical technologies advance, ideas about when death occurs may have to be re-evaluated in light of the ability to restore a person to vitality after longer periods of apparent death (as happened when CPR and defibrillation showed that cessation of heartbeat is inadequate as a decisive indicator of death). The lack of electrical brain activity may not be enough to consider someone scientifically dead. Therefore, the concept of information theoretical death
Information theoretical death
Information-theoretic death is the destruction of the information within a human brain to such an extent that recovery of the original person is theoretically impossible by any physical means...

 has been suggested as a better means of defining when true death occurs, though the concept has few practical applications outside of the field of cryonics
Cryonics
Cryonics is the low-temperature preservation of humans and animals who can no longer be sustained by contemporary medicine, with the hope that healing and resuscitation may be possible in the future. Cryopreservation of people or large animals is not reversible with current technology...

.

There have been some scientific attempts to bring dead organisms back to life, but with limited success. In science fiction
Science fiction
Science fiction is a genre of fiction dealing with imaginary but more or less plausible content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities...

 scenario
Scenario
A scenario is a synoptical collage of an event or series of actions and events. In the Commedia dell'arte it was an outline of entrances, exits, and action describing the plot of a play that was literally pinned to the back of the scenery...

s where such technology is readily available, real death is distinguished from reversible death.

Causes



The leading cause of death in developing countries is infectious disease
Infectious disease
Infectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...

. The leading causes of death in developed countries are atherosclerosis
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...

 (heart disease
Heart disease
Heart disease, cardiac disease or cardiopathy is an umbrella term for a variety of diseases affecting the heart. , it is the leading cause of death in the United States, England, Canada and Wales, accounting for 25.4% of the total deaths in the United States.-Types:-Coronary heart disease:Coronary...

 and stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...

), cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

, and other diseases related to obesity
Obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...

 and aging. These conditions cause loss of homeostasis
Homeostasis
Homeostasis is the property of a system that regulates its internal environment and tends to maintain a stable, constant condition of properties like temperature or pH...

, leading to cardiac arrest
Cardiac arrest
Cardiac arrest, is the cessation of normal circulation of the blood due to failure of the heart to contract effectively...

, causing loss of oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 and nutrient supply, causing irreversible deterioration of the brain
Human brain
The human brain has the same general structure as the brains of other mammals, but is over three times larger than the brain of a typical mammal with an equivalent body size. Estimates for the number of neurons in the human brain range from 80 to 120 billion...

 and other tissues
Tissue (biology)
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...

. Of the roughly 150,000 people who die each day across the globe, about two thirds die of age-related causes. In industrialized nations, the proportion is much higher, reaching 90%. With improved medical capability, dying has become a condition to be managed
Respite care
Respite care is the provision of short-term, temporary relief to those who are caring for family members who might otherwise require permanent placement in a facility outside the home....

. Home deaths, once commonplace, are now rare in the developed world.


In developing nations, inferior sanitary conditions and lack of access to modern medical technology
Medical technology
Medical Technology encompasses a wide range of healthcare products and is used to diagnose, monitor or treat diseases or medical conditions affecting humans. Such technologies are intended to improve the quality of healthcare delivered through earlier diagnosis, less invasive treatment options and...

 makes death from infectious diseases more common than in developed countries. One such disease is tuberculosis
Tuberculosis
Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...

, a bacterial disease which killed 1.7 million people in 2004. Malaria
Malaria
Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...

 causes about 400–900 million cases of fever and 1–3 million deaths annually. AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...

 death toll in Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

 may reach 90–100 million by 2025.

According to Jean Ziegler
Jean Ziegler
Jean Ziegler is a former professor of sociology at the University of Geneva and the Sorbonne, Paris. He was a Member of Parliament for the Social Democrats in the Federal Assembly of Switzerland from 1981 to 1999...

, who was the United Nations
United Nations
The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...

 Special reporter on the Right to Food from 2000 to March 2008, mortality due to malnutrition
Malnutrition
Malnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions....

 accounted for 58% of the total mortality rate in 2006. Ziegler says worldwide approximately 62 million people died from all causes and of those deaths more than 36 million died of hunger or diseases due to deficiencies in micronutrients.

Tobacco
Tobacco
Tobacco is an agricultural product processed from the leaves of plants in the genus Nicotiana. It can be consumed, used as a pesticide and, in the form of nicotine tartrate, used in some medicines...

 smoking killed 100 million people worldwide in the 20th century and could kill 1 billion people around the world in the 21st century, a WHO
Who
Who may refer to:* Who , an English-language pronoun* who , a Unix command* Who?, one of the Five Ws in journalism- Art and entertainment :* Who? , a 1958 novel by Algis Budrys...

 Report warned.

Many leading developed world causes of death can be postponed by diet
Diet (nutrition)
In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management...

 and physical activity
Physical fitness
Physical fitness comprises two related concepts: general fitness , and specific fitness...

, but the accelerating incidence of disease with age still imposes limits on human longevity
Longevity
The word "longevity" is sometimes used as a synonym for "life expectancy" in demography or known as "long life", especially when it concerns someone or something lasting longer than expected ....

. The evolutionary cause of aging is, at best, only just beginning to be understood. It has been suggested that direct intervention in the aging process may now be the most effective intervention against major causes of death.

Autopsy


An autopsy
Autopsy
An autopsy—also known as a post-mortem examination, necropsy , autopsia cadaverum, or obduction—is a highly specialized surgical procedure that consists of a thorough examination of a corpse to determine the cause and manner of death and to evaluate any disease or injury that may be present...

, also known as a postmortem examination or an obduction, is a medical procedure
Medical procedure
A medical procedure is a course of action intended to achieve a result in the care of persons with health problems.A medical procedure with the intention of determining, measuring or diagnosing a patient condition or parameter is also called a medical test...

 that consists of a thorough examination of a human corpse to determine the cause and manner of a person's death and to evaluate any disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...

 or injury
Injury
-By cause:*Traumatic injury, a body wound or shock produced by sudden physical injury, as from violence or accident*Other injuries from external physical causes, such as radiation injury, burn injury or frostbite*Injury from infection...

 that may be present. It is usually performed by a specialized medical doctor
Physician
A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...

 called a pathologist.


Autopsies are either performed for legal or medical purposes. A forensic autopsy is carried out when the cause of death may be a criminal matter, while a clinical or academic autopsy is performed to find the medical cause of death and is used in cases of unknown or uncertain death, or for research purposes. Autopsies can be further classified into cases where external examination suffices, and those where the body is dissected and an internal examination is conducted. Permission from next of kin
Next of kin
Next of kin is a term with many interpretations depending on the jurisdiction being referred to. In some jurisdictions, such as the United States, it is used to describe a person's closest living blood relative or relatives...

 may be required for internal autopsy in some cases. Once an internal autopsy is complete the body is generally reconstituted by sewing it back together. Autopsy is important in a medical environment and may shed light on mistakes and help improve practices.

A "necropsy" is an older term for a postmortem examination, unregulated, and not always a medical procedure. In modern times the term is more often used in the postmortem examination of the corpses of animals.

Life extension



Life extension
Life extension
Life extension science, also known as anti-aging medicine, experimental gerontology, and biomedical gerontology, is the study of slowing down or reversing the processes of aging to extend both the maximum and average lifespan...

 refers to an increase in maximum
Maximum life span
Maximum life span is a measure of the maximum amount of time one or more members of a population has been observed to survive between birth and death.Most living species have at least one upper limit on the number of times cells can divide...

 or average lifespan
Life expectancy
Life expectancy is the expected number of years of life remaining at a given age. It is denoted by ex, which means the average number of subsequent years of life for someone now aged x, according to a particular mortality experience...

, especially in humans, by slowing down or reversing the processes of aging
Senescence
Senescence or biological aging is the change in the biology of an organism as it ages after its maturity. Such changes range from those affecting its cells and their function to those affecting the whole organism...

. Average lifespan is determined by vulnerability to accident
Accident
An accident or mishap is an unforeseen and unplanned event or circumstance, often with lack of intention or necessity. It implies a generally negative outcome which may have been avoided or prevented had circumstances leading up to the accident been recognized, and acted upon, prior to its...

s and age or lifestyle-related afflictions such as cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

, or cardiovascular disease
Cardiovascular disease
Heart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...

. Extension of average lifespan can be achieved by good diet
Diet (nutrition)
In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management...

, exercise and avoidance of hazards such as smoking
Tobacco smoking
Tobacco smoking is the practice where tobacco is burned and the resulting smoke is inhaled. The practice may have begun as early as 5000–3000 BCE. Tobacco was introduced to Eurasia in the late 16th century where it followed common trade routes...

. Maximum lifespan is determined by the rate of aging for a species inherent in its gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

s. Currently, the only widely recognized method of extending maximum lifespan is calorie restriction
Calorie restriction
Caloric restriction , or calorie restriction, is a dietary regimen that restricts calorie intake, where the baseline for the restriction varies, usually being the previous, unrestricted, intake of the subjects...

. Theoretically, extension of maximum lifespan can be achieved by reducing the rate of aging damage, by periodic replacement of damaged tissues
Tissue engineering
Tissue engineering is the use of a combination of cells, engineering and materials methods, and suitable biochemical and physio-chemical factors to improve or replace biological functions...

, or by molecular repair
Nanobiotechnology
Bionanotechnology, nanobiotechnology, and nanobiology are terms that refer to the intersection of nanotechnology and biology. Given that the subject is one that has only emerged very recently, bionanotechnology and nanobiotechnology serve as blanket terms for various related technologies.This...

 or rejuvenation
Rejuvenation (aging)
Rejuvenation is the hypothetical reversal of the aging process.Rejuvenation is distinct from life extension. Life extension strategies often study the causes of aging and try to oppose those causes in order to slow aging...

 of deteriorated cells and tissues.

Researchers of life extension are a subclass of biogerontologists known as "biomedical gerontologists". They try to understand the nature of aging and they develop treatments to reverse aging processes or to at least slow them down, for the improvement of health and the maintenance of youthful vigor at every stage of life. Those who take advantage of life extension findings and seek to apply them upon themselves are called "life extensionists" or "longevists". The primary life extension strategy currently is to apply available anti-aging methods in the hope of living long enough to benefit from a complete cure to aging once it is developed, which given the rapidly advancing state of biogenetic and general medical technology, could conceivably occur within the lifetimes of people living today.

Location


Before about 1930, most people died in their own homes, surrounded by family, and comforted by clergy, neighbors, and doctors making house call
House Call
Sanjay Gupta MD is a medical-centric news program hosted by CNN's in-house physician, Sanjay Gupta. It typically airs on weekends at 7:30 am E.T....

s. By the mid-20th century, half of all Americans died in a hospital. By the start of the 21st century, only about 20 to 25% of people in developed countries died outside of a medical institution. The shift away from dying at home, towards dying in a professionalized medical environment, has been termed the "Invisible Death".

Society and culture


Death is the center of many traditions and organizations; customs relating to death are a feature of every culture around the world. Much of this revolves around the care of the dead, as well as the afterlife
Afterlife
The afterlife is the belief that a part of, or essence of, or soul of an individual, which carries with it and confers personal identity, survives the death of the body of this world and this lifetime, by natural or supernatural means, in contrast to the belief in eternal...

 and the disposal of bodies upon the onset of death. The disposal of human corpses
Disposal of human corpses
Disposal of human corpses is the practice and process of dealing with the remains of a deceased human being. Human corpses present both a sanitation and public health risk. Like most animals, when humans die, their bodies start to decompose, emitting a foul odor and attracting scavengers and...

 does, in general, begin with the last offices
Last offices
The last offices are the procedures performed, usually by a nurse in the developed world, to a dead person shortly after death has been confirmed. They can vary from hospital to hospital, and culture to culture.-Name:...

 before significant time has passed, and ritualistic ceremonies often occur, most commonly interment or cremation
Cremation
Cremation is the process of reducing bodies to basic chemical compounds such as gasses and bone fragments. This is accomplished through high-temperature burning, vaporization and oxidation....

. This is not a unified practice, however, as in Tibet
Tibet
Tibet is a plateau region in Asia, north-east of the Himalayas. It is the traditional homeland of the Tibetan people as well as some other ethnic groups such as Monpas, Qiang, and Lhobas, and is now also inhabited by considerable numbers of Han and Hui people...

 for instance the body is given a sky burial
Sky burial
Sky burial, or ritual dissection, is a funerary practice in Tibet, wherein a human corpse was incised in certain locations and placed on a mountaintop, exposing it to the elements and animals – especially to predatory birds. The locations of preparation and sky burial are understood in the...

 and left on a mountain top. Proper preparation for death and techniques and ceremonies for producing the ability to transfer one's spiritual attainments into another body (reincarnation
Reincarnation
Reincarnation best describes the concept where the soul or spirit, after the death of the body, is believed to return to live in a new human body, or, in some traditions, either as a human being, animal or plant...

) are subjects of detailed study in Tibet. Mummification or embalming
Embalming
Embalming, in most modern cultures, is the art and science of temporarily preserving human remains to forestall decomposition and to make them suitable for public display at a funeral. The three goals of embalming are thus sanitization, presentation and preservation of a corpse to achieve this...

 is also prevalent in some cultures, to retard the rate of decay
Decomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...

.

Legal aspects of death are also part of many cultures, particularly the settlement of the deceased estate
Estate (law)
An estate is the net worth of a person at any point in time. It is the sum of a person's assets - legal rights, interests and entitlements to property of any kind - less all liabilities at that time. The issue is of special legal significance on a question of bankruptcy and death of the person...

 and the issues of inheritance
Inheritance
Inheritance is the practice of passing on property, titles, debts, rights and obligations upon the death of an individual. It has long played an important role in human societies...

 and in some countries, inheritance tax
Inheritance tax
An inheritance tax or estate tax is a levy paid by a person who inherits money or property or a tax on the estate of a person who has died...

ation.
Capital punishment
Capital punishment
Capital punishment, the death penalty, or execution is the sentence of death upon a person by the state as a punishment for an offence. Crimes that can result in a death penalty are known as capital crimes or capital offences. The term capital originates from the Latin capitalis, literally...

 is also a culturally divisive aspect of death. In most jurisdictions where capital punishment is carried out today, the death penalty is reserved for premeditated murder
Murder
Murder is the unlawful killing, with malice aforethought, of another human being, and generally this state of mind distinguishes murder from other forms of unlawful homicide...

, espionage
Espionage
Espionage or spying involves an individual obtaining information that is considered secret or confidential without the permission of the holder of the information. Espionage is inherently clandestine, lest the legitimate holder of the information change plans or take other countermeasures once it...

, treason
Treason
In law, treason is the crime that covers some of the more extreme acts against one's sovereign or nation. Historically, treason also covered the murder of specific social superiors, such as the murder of a husband by his wife. Treason against the king was known as high treason and treason against a...

, or as part of military justice. In some countries, sexual crimes, such as adultery
Adultery
Adultery is sexual infidelity to one's spouse, and is a form of extramarital sex. It originally referred only to sex between a woman who was married and a person other than her spouse. Even in cases of separation from one's spouse, an extramarital affair is still considered adultery.Adultery is...

 and sodomy
Sodomy
Sodomy is an anal or other copulation-like act, especially between male persons or between a man and animal, and one who practices sodomy is a "sodomite"...

, carry the death penalty, as do religious crimes such as apostasy
Apostasy
Apostasy , 'a defection or revolt', from ἀπό, apo, 'away, apart', στάσις, stasis, 'stand, 'standing') is the formal disaffiliation from or abandonment or renunciation of a religion by a person. One who commits apostasy is known as an apostate. These terms have a pejorative implication in everyday...

, the formal renunciation of one's religion. In many retentionist countries, drug trafficking is also a capital offense. In China human trafficking and serious cases of corruption
Political corruption
Political corruption is the use of legislated powers by government officials for illegitimate private gain. Misuse of government power for other purposes, such as repression of political opponents and general police brutality, is not considered political corruption. Neither are illegal acts by...

 are also punished by the death penalty. In militaries around the world courts-martial have imposed death sentences for offenses such as cowardice
Cowardice
Cowardice is the perceived failure to demonstrate sufficient mental robustness and courage in the face of a challenge. Under many military codes of justice, cowardice in the face of combat is a crime punishable by death...

, desertion
Desertion
In military terminology, desertion is the abandonment of a "duty" or post without permission and is done with the intention of not returning...

, insubordination
Insubordination
Insubordination is the act of willfully disobeying an authority. Refusing to perform an action that is unethical or illegal is not insubordination; neither is refusing to perform an action that is not within the scope of authority of the person issuing the order.Insubordination is typically a...

, and mutiny
Mutiny
Mutiny is a conspiracy among members of a group of similarly situated individuals to openly oppose, change or overthrow an authority to which they are subject...

.

Death in warfare and in suicide attack
Suicide attack
A suicide attack is a type of attack in which the attacker expects or intends to die in the process.- Historical :...

 also have cultural links, and the ideas of dulce et decorum est pro patria mori
Dulce et decorum est pro patria mori
Dulce et decorum est pro patria mori is a line from the Roman lyrical poet Horace's Odes . The line can be roughly translated into English as: "It is sweet and fitting to die for one's country."-Context:...

, mutiny
Mutiny
Mutiny is a conspiracy among members of a group of similarly situated individuals to openly oppose, change or overthrow an authority to which they are subject...

 punishable by death, grieving relatives of dead soldiers and death notification
Death notification
A death notification is a letter delivered to the family of a soldier or public service member who has died on duty. Usually, the Military of the United States withholds the name of a deceased member until the family has been notified....

 are embedded in many cultures. Recently in the western world, with the supposed increase in terrorism following the September 11 attacks, but also further back in time with suicide bombings, kamikaze
Kamikaze
The were suicide attacks by military aviators from the Empire of Japan against Allied naval vessels in the closing stages of the Pacific campaign of World War II, designed to destroy as many warships as possible....

 missions in World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 and suicide missions in a host of other conflicts in history, death for a cause by way of suicide attack, and martyrdom have had significant cultural impacts.

Suicide
Suicide
Suicide is the act of intentionally causing one's own death. Suicide is often committed out of despair or attributed to some underlying mental disorder, such as depression, bipolar disorder, schizophrenia, alcoholism, or drug abuse...

 in general, and particularly euthanasia
Euthanasia
Euthanasia refers to the practice of intentionally ending a life in order to relieve pain and suffering....

, are also points of cultural debate. Both acts are understood very differently in different cultures. In Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

, for example, ending a life with honor by seppuku
Seppuku
is a form of Japanese ritual suicide by disembowelment. Seppuku was originally reserved only for samurai. Part of the samurai bushido honor code, seppuku was either used voluntarily by samurai to die with honor rather than fall into the hands of their enemies , or as a form of capital punishment...

 was considered a desirable death, whereas according to traditional Christian and Islamic cultures, suicide
Suicide
Suicide is the act of intentionally causing one's own death. Suicide is often committed out of despair or attributed to some underlying mental disorder, such as depression, bipolar disorder, schizophrenia, alcoholism, or drug abuse...

 is viewed as a sin. Death is personified
Death (personification)
The concept of death as a sentient entity has existed in many societies since the beginning of history. In English, Death is often given the name Grim Reaper and, from the 15th century onwards, came to be shown as a skeletal figure carrying a large scythe and clothed in a black cloak with a hood...

 in many cultures, with such symbolic representations as the Grim Reaper, Azrael
Azrael
Azrael is the name of the Archangel of Death in some extrabiblical traditions. He is also the angel of death in Islamic theology and Sikhism. It is an English form of the Arabic name ʿIzrāʾīl or Azra'eil , the name traditionally attributed to the angel of death in some sects of Islam and Sikhism,...

 and Father Time
Father Time
Father Time is usually depicted as an elderly bearded man, somewhat worse for wear, dressed in a robe, carrying a scythe and an hourglass or other timekeeping device...

.

In biology


After death the remains of an organism become part of the biogeochemical cycle
Biogeochemical cycle
In ecology and Earth science, a biogeochemical cycle or substance turnover or cycling of substances is a pathway by which a chemical element or molecule moves through both biotic and abiotic compartments of Earth. A cycle is a series of change which comes back to the starting point and which can...

. Animals may be consumed by a predator or a scavenger
Scavenger
Scavenging is both a carnivorous and herbivorous feeding behavior in which individual scavengers search out dead animal and dead plant biomass on which to feed. The eating of carrion from the same species is referred to as cannibalism. Scavengers play an important role in the ecosystem by...

. Organic material may then be further decomposed by detritivore
Detritivore
Detritivores, also known as detritophages or detritus feeders or detritus eaters or saprophages, are heterotrophs that obtain nutrients by consuming detritus . By doing so, they contribute to decomposition and the nutrient cycles...

s, organisms which recycle detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...

, returning it to the environment for reuse in the food chain
Food chain
A food web depicts feeding connections in an ecological community. Ecologists can broadly lump all life forms into one of two categories called trophic levels: 1) the autotrophs, and 2) the heterotrophs...

. Examples of detritivores include earthworm
Earthworm
Earthworm is the common name for the largest members of Oligochaeta in the phylum Annelida. In classical systems they were placed in the order Opisthopora, on the basis of the male pores opening posterior to the female pores, even though the internal male segments are anterior to the female...

s, woodlice and dung beetles.

Microorganism
Microorganism
A microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...

s also play a vital role, raising the temperature of the decomposing matter as they break it down into yet simpler molecules. Not all materials need to be decomposed fully, however. Coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

, a fossil fuel
Fossil fuel
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...

 formed over vast tracts of time in swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...

 ecosystems, is one example.

Natural selection



Contemporary evolutionary theory
History of evolutionary thought
Evolutionary thought, the conception that species change over time, has roots in antiquity, in the ideas of the ancient Greeks, Romans, and Chinese as well as in medieval Islamic science...

 sees death as an important part of the process of natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....

. It is considered that organisms less adapted
Adaptation
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....

 to their environment are more likely to die having produced fewer offspring, thereby reducing their contribution to the gene pool
Gene pool
In population genetics, a gene pool is the complete set of unique alleles in a species or population.- Description :A large gene pool indicates extensive genetic diversity, which is associated with robust populations that can survive bouts of intense selection...

. Their genes are thus eventually bred out of a population, leading at worst to extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...

 and, more positively, making the process possible, referred to as speciation
Speciation
Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...

. Frequency of reproduction
Biological reproduction
Reproduction is the biological process by which new "offspring" individual organisms are produced from their "parents". Reproduction is a fundamental feature of all known life; each individual organism exists as the result of reproduction...

 plays an equally important role in determining species survival: an organism that dies young but leaves numerous offspring displays, according to Darwinian
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...

 criteria, much greater fitness than a long-lived organism leaving only one.

Extinction




Extinction is the cessation of existence of a species or group of taxa, reducing biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...

. The moment of extinction is generally considered to be the death of the last individual of that species (although the capacity to breed and recover
Population bottleneck
A population bottleneck is an evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented from reproducing....

 may have been lost before this point). Because a species' potential range
Range (biology)
In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...

 may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa
Lazarus taxon
In paleontology, a Lazarus taxon is a taxon that disappears from one or more periods of the fossil record, only to appear again later. The term refers to the account in the Gospel of John, in which Jesus raised Lazarus from the dead...

, where a species presumed extinct abruptly "reappears" (typically in the fossil record
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

) after a period of apparent absence. New species arise through the process of speciation
Speciation
Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...

, an aspect of evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

. New varieties of organisms arise and thrive when they are able to find and exploit an ecological niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...

 – and species become extinct when they are no longer able to survive in changing conditions or against superior competition.

Evolution of aging



Inquiry into the evolution of aging aims to explain why so many living things and the vast majority of animals weaken and die with age (a notable exception being hydra
Hydra (genus)
Hydra is a genus of simple fresh-water animal possessing radial symmetry. Hydras are predatory animals belonging to the phylum Cnidaria and the class Hydrozoa. They can be found in most unpolluted fresh-water ponds, lakes, and streams in the temperate and tropical regions and can be found by...

, which may be biologically immortal
Biological immortality
Biological immortality refers to a stable rate of mortality as a function of chronological age. Some individual cells and entire organisms in some species achieve this state either throughout their existence or after living long enough. This requires that death occur from injury or disease rather...

). The evolutionary origin of senescence
Senescence
Senescence or biological aging is the change in the biology of an organism as it ages after its maturity. Such changes range from those affecting its cells and their function to those affecting the whole organism...

 remains one of the fundamental puzzles of biology. Gerontology
Gerontology
Gerontology is the study of the social, psychological and biological aspects of aging...

 specializes in the science of human aging processes.

See also


  • Afterlife
    Afterlife
    The afterlife is the belief that a part of, or essence of, or soul of an individual, which carries with it and confers personal identity, survives the death of the body of this world and this lifetime, by natural or supernatural means, in contrast to the belief in eternal...

  • Cadaveric spasm
    Cadaveric spasm
    Cadaveric spasm, also known as instantaneous rigor, cataleptic rigidity, or instantaneous rigidity, is a rare form of muscular stiffening that occurs at the moment of death, persists into the period of rigor mortis and can be mistaken for rigor mortis...

  • Capital punishment
    Capital punishment
    Capital punishment, the death penalty, or execution is the sentence of death upon a person by the state as a punishment for an offence. Crimes that can result in a death penalty are known as capital crimes or capital offences. The term capital originates from the Latin capitalis, literally...

  • Day of the Dead
    Day of the Dead
    Day of the Dead is a Mexican holiday celebrated throughout Mexico and around the world in many cultures. The holiday focuses on gatherings of family and friends to pray for and remember friends and family members who have died. It is particularly celebrated in Mexico, where it attains the quality...

  • Dead bell
    Dead bell
    A Dead bell or deid bell , also a 'death', 'mort', 'lych', 'passing bell' or 'skellet bell' was a form of hand bell used in Scotland and northern England. in conjunction with deaths and funerals up until the 19th century.-Origins:...

  • Death (personification)
    Death (personification)
    The concept of death as a sentient entity has existed in many societies since the beginning of history. In English, Death is often given the name Grim Reaper and, from the 15th century onwards, came to be shown as a skeletal figure carrying a large scythe and clothed in a black cloak with a hood...

  • Death drive
  • Death erection
    Death erection
    A death erection, angel lust, or terminal erection is a post-mortem erection, technically a priapism, observed in the corpses of human males who have been executed, particularly by hanging.-Overview:...

  • Death messengers
    Death messengers
    Death messengers, in former times, were those who were dispatched to spread the news that an inhabitant of their city or village had died. They were to wear unadorned black and go door to door with the message, "You are asked to attend the funeral of the departed __________ at ." This was all...

  • Death rattle
    Death rattle
    A death rattle is a medical term that describes the sound produced by someone who is near death when saliva accumulates in the throat. Those who are dying may lose their ability to swallow, resulting in such an accumulation...

  • Death row
    Death row
    Death row signifies the place, often a section of a prison, that houses individuals awaiting execution. The term is also used figuratively to describe the state of awaiting execution , even in places where no special facility or separate unit for condemned inmates exists.After individuals are found...

  • Dying declaration
    Dying declaration
    In the law of evidence, the dying declaration is testimony that would normally barred as hearsay but may nonetheless be admitted as evidence in certain kinds of cases because it constituted the last words of a dying person.-History:...

  • End-of-life care
  • Ethereal being
    Ethereal being
    Ethereal beings, according to some belief systems and occult theories, are mystic entities that usually are not made of ordinary matter. Despite the fact that they are believed to be essentially incorporeal, they do interact in physical shapes with the material universe and travel between the...

  • Faked death
    Faked death
    A faked death occurs when an individual leaves evidence to suggest that he or she is dead in order to mislead others. This may be done for a variety of reasons, such as to fraudulently collect insurance money or avoid capture by law enforcement for some other crime.People who fake their own deaths...

  • Ghost
    Ghost
    In traditional belief and fiction, a ghost is the soul or spirit of a deceased person or animal that can appear, in visible form or other manifestation, to the living. Descriptions of the apparition of ghosts vary widely from an invisible presence to translucent or barely visible wispy shapes, to...

  • Information-theoretic death
  • International Necronautical Society
    International Necronautical Society
    The International Necronautical Society is a semi-fictional organization closely modeled on European avant-gardes of the early 20th century. It replays, not without parody, the politically-inflected structures of these avant-gardes, with their manifestoes, committees, splinter groups and purges...

  • Karōshi
    Karoshi
    , which can be translated literally from Japanese as "death from overwork", is occupational sudden death. Although this category has a significant count, Japan is one of the few countries that reports it in the statistics as a separate category...

  • Last Rites
    Last Rites
    The Last Rites are the very last prayers and ministrations given to many Christians before death. The last rites go by various names and include different practices in different Christian traditions...

  • List of preventable causes of death
  • Makeshift memorial
  • Nats (spirits)
  • Near death experience
    Near death experience
    A near-death experience refers to a broad range of personal experiences associated with impending death, encompassing multiple possible sensations including detachment from the body; feelings of levitation; extreme fear; total serenity, security, or warmth; the experience of absolute dissolution;...

  • Origin of death myth
    Origin of death myth
    The origin of death is a theme in the myths of many cultures. Death is a universal feature of human life, so stories about its origin appear to be universal in human cultures. As such it is a form of cosmological myth...

  • Post-mortem interval
  • Spiritual death
    Spiritual death
    In Christian theology, spiritual death is separation from God. Humans are separated from God because of sin, which entered the world through the Fall of Man, and are reconciled to God through the atoning sacrifice of Jesus Christ....

  • Survivalism (life after death)
    Survivalism (life after death)
    Survivalism refers to the belief in the survival of the conscious self after the death of the physical body. Survivalists attempt to prove survival with the methods of science, using as evidence such things as psychic phenomena, near-death experiences, out-of-body experiences, electronic voice...

  • Taboo on the dead
    Taboo on the dead
    The taboo on the dead includes the taboo against touching of the dead and those surrounding them; the taboo against mourners of the dead; and the taboo against anything associated with the dead.-Examples:...

  • Thanatology
    Thanatology
    Thanatology is the scientific study of death. It investigates the mechanisms and forensic aspects of death, such as bodily changes that accompany death and the post-mortem period, as well as wider social aspects related to death. It is primarily an interdisciplinary study offered as a course of...

  • Thanatosensitivity
    Thanatosensitivity
    Thanatosensitivity describes an epistemological-methodological approach into technological research and design that actively seeks to integrate the facts of mortality, dying, and death into traditional user-centred design...

  • Vampire
    Vampire
    Vampires are mythological or folkloric beings who subsist by feeding on the life essence of living creatures, regardless of whether they are undead or a living person...

  • Yurei
    Yurei
    are figures in Japanese folklore, analogous to Western legends of ghosts. The name consists of two kanji, 幽 , meaning "faint" or "dim" and 霊 , meaning "soul" or "spirit." Alternative names include 亡霊 meaning ruined or departed spirit, 死霊 meaning dead spirit, or the more encompassing 妖怪 or お化け...

  • Zombie
    Zombie
    Zombie is a term used to denote an animated corpse brought back to life by mystical means such as witchcraft. The term is often figuratively applied to describe a hypnotized person bereft of consciousness and self-awareness, yet ambulant and able to respond to surrounding stimuli...



Further reading

  • Appel, JM. Defining Death: When Physicians and Families Differ. Journal of Medical Ethics Fall 2005.
  • Child AM (1995) J Archaeolog Sci 22: 165-174it funny
  • Piepenbrink H (1985) J Archaeolog Sci 13: 417-430
  • Piepenbrink H (1989) Applied Geochem 4: 273-280
  • Vass AA (2001) Microbiology Today 28: 190-192 at SGM.ac.uk

External links