Self-preservation is a behavior or set of behaviors that ensures the survival of an organism. [1] It is thought to be universal among all living organisms. For sentient organisms, pain and fear are integral parts of this mechanism. Pain motivates the individual to withdraw from damaging situations, to protect a damaged body part while it heals, and to avoid similar experiences in the future. [2] Most pain resolves promptly once the painful stimulus is removed and the body has healed, but sometimes pain persists despite removal of the stimulus and apparent healing of the body; and sometimes pain arises in the absence of any detectable stimulus, damage or disease. [3] Fear causes the organism to seek safety and may cause a release of adrenaline, [4] [5] which has the effect of increased strength and heightened senses such as hearing, smell, and sight. Self-preservation may also be interpreted figuratively, in regard to the coping mechanisms one needs to prevent emotional trauma from distorting the mind (see Defence mechanisms).
Even the most simple of living organisms (for example, the single-celled bacteria) are typically under intense selective pressure to evolve a response that would help avoid a damaging environment, if such an environment exists. Organisms also evolve while adapting –even thriving –in a benign environment (for example, a marine sponge modifies its structure in response to current changes, in order to better absorb and process nutrients). Self-preservation is therefore an almost universal hallmark of life. However, when introduced to a novel threat, many species will have a self-preservation response either too specialised, or not specialised enough, to cope with that particular threat.[ citation needed ] An example is the dodo, which evolved in the absence of natural predators and hence lacked an appropriate, general self-preservation response to heavy predation by humans and rats, showing no fear of them.
Self-preservation is essentially the process of an organism preventing itself from being harmed or killed and is considered a basic instinct in most organisms. [6] Most call it a "survival instinct". Self-preservation is thought to be tied to an organism's reproductive fitness and can be more or less present according to perceived reproduction potential. [7] If perceived reproductive potential is low enough, self-destructive behavior (i.e., the opposite) is not uncommon in social species. [8] Self-preservation is also thought by some to be the basis of rational and logical thought and behavior. [9]
An organism's fitness is measured by its ability to pass on its genes. The most straightforward way to accomplish this is to survive to a reproductive age, mate, and then have offspring. These offspring will hold at least a portion of their parent's genes, up to all of the parent's genes in asexual organisms. But in order for this to happen, an organism must first survive long enough to reproduce, and this would mainly consist of adopting selfish behaviors that would allow organisms to maximize their own chances for survival.
Animals in a social group (of kin) often work cooperatively in order to survive, but when one member perceives itself as a burden for an extended period of time, it may commit self-destructive behavior. [7] This allows its relatives to have a better chance at survival, and if enough close relatives survive, then its genes get indirectly passed on. [7] This behavior works in the exact opposite direction of the survival instinct and could be considered a highly altruistic behavior evolved from a cooperative group. Self-destructive behavior is not the same as risk-taking behavior (see below in Social implications), although risk-taking behavior could turn into destructive behavior.
The desire for self-preservation has led to countless laws and regulations surrounding a culture of safety in society. [10] Seat belt laws, speed limits, texting regulations, and the "stranger danger" campaign are examples of societal guides and regulations to enhance survival, and these laws are heavily influenced by the pursuit of self-preservation.
Self-preservation urges animals to collect energy and resources required to prolong life as well as resources that increase chances of survival. Basic needs are available to most humans (roughly 7 out of 8 people), [11] and usually rather cheaply. The instinct that drives humans to gather resources now drives them to over-consumption or to patterns of collection and possession that essentially make hoarding resources the priority. [12]
Self-preservation is not just limited to individual organisms; this can be scaled up or down to other levels of life. Narula and Young [13] indicate that cardiac myocytes have an acute sense of self-preservation. They are able to duck, dart, and dodge foreign substances that may harm the cell. In addition, when a myocardiac arrest –a heart attack –occurs, it is actually the cardiac myocytes entering a state of hibernation in an attempt to wait out a lack of resources. [13] While this is ultimately deadly to the organism, it prolongs the cell's survival as long as possible for hopeful resuscitation. [13]
When scaled in the opposite direction, Hughes-Jones [14] makes the argument that "social groups that fight each other are self‐sustaining, self‐replicating wholes containing interdependent parts" indicating that the group as a whole can have self-preservation with the individuals acting as the cells.
He makes an analogy between the survival practices such as hygiene and the ritual nature within small human groups or the nations that engage in religious warfare with the complex survival mechanisms of multi-cellular organisms that evolved from the cooperative association of single cell organisms in order to better protect themselves.[ clarification needed ]
Ethology is a branch of zoology that studies the behaviour of non-human animals. It has its scientific roots in the work of Charles Darwin and of American and German ornithologists of the late 19th and early 20th century, including Charles O. Whitman, Oskar Heinroth, and Wallace Craig. The modern discipline of ethology is generally considered to have begun during the 1930s with the work of the Dutch biologist Nikolaas Tinbergen and the Austrian biologists Konrad Lorenz and Karl von Frisch, the three winners of the 1973 Nobel Prize in Physiology or Medicine. Ethology combines laboratory and field science, with a strong relation to neuroanatomy, ecology, and evolutionary biology.
Evolutionary psychology is a theoretical approach in psychology that examines cognition and behavior from a modern evolutionary perspective. It seeks to identify human psychological adaptations with regards to the ancestral problems they evolved to solve. In this framework, psychological traits and mechanisms are either functional products of natural and sexual selection or non-adaptive by-products of other adaptive traits.
Reproduction is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. There are two forms of reproduction: asexual and sexual.
Kin selection is a process whereby natural selection favours a trait due to its positive effects on the reproductive success of an organism's relatives, even when at a cost to the organism's own survival and reproduction. Kin selection can lead to the evolution of altruistic behaviour. It is related to inclusive fitness, which combines the number of offspring produced with the number an individual can ensure the production of by supporting others. A broader definition of kin selection includes selection acting on interactions between individuals who share a gene of interest even if the gene is not shared due to common ancestry.
Instinct is the inherent inclination of a living organism towards a particular complex behaviour, containing innate (inborn) elements. The simplest example of an instinctive behaviour is a fixed action pattern (FAP), in which a very short to medium length sequence of actions, without variation, are carried out in response to a corresponding clearly defined stimulus.
A supernormal stimulus or superstimulus is an exaggerated version of a stimulus to which there is an existing response tendency, or any stimulus that elicits a response more strongly than the stimulus for which it evolved.
Cooperation takes place when a group of organisms works or acts together for a collective benefit to the group as opposed to working in competition for selfish individual benefit. In biology, many animal and plant species cooperate both with other members of their own species and with members of other species with whom they have relationships.
In physiology, a stimulus is a detectable change in the physical or chemical structure of an organism's internal or external environment. The ability of an organism or organ to detect external stimuli, so that an appropriate reaction can be made, is called sensitivity (excitability). Sensory receptors can receive information from outside the body, as in touch receptors found in the skin or light receptors in the eye, as well as from inside the body, as in chemoreceptors and mechanoreceptors. When a stimulus is detected by a sensory receptor, it can elicit a reflex via stimulus transduction. An internal stimulus is often the first component of a homeostatic control system. External stimuli are capable of producing systemic responses throughout the body, as in the fight-or-flight response. In order for a stimulus to be detected with high probability, its level of strength must exceed the absolute threshold; if a signal does reach threshold, the information is transmitted to the central nervous system (CNS), where it is integrated and a decision on how to react is made. Although stimuli commonly cause the body to respond, it is the CNS that finally determines whether a signal causes a reaction or not.
A psychological adaptation is a functional, cognitive or behavioral trait that benefits an organism in its environment. Psychological adaptations fall under the scope of evolved psychological mechanisms (EPMs), however, EPMs refer to a less restricted set. Psychological adaptations include only the functional traits that increase the fitness of an organism, while EPMs refer to any psychological mechanism that developed through the processes of evolution. These additional EPMs are the by-product traits of a species’ evolutionary development, as well as the vestigial traits that no longer benefit the species’ fitness. It can be difficult to tell whether a trait is vestigial or not, so some literature is more lenient and refers to vestigial traits as adaptations, even though they may no longer have adaptive functionality. For example, xenophobic attitudes and behaviors, some have claimed, appear to have certain EPM influences relating to disease aversion, however, in many environments these behaviors will have a detrimental effect on a person's fitness. The principles of psychological adaptation rely on Darwin's theory of evolution and are important to the fields of evolutionary psychology, biology, and cognitive science.
Enquiry into the evolution of ageing, or aging, aims to explain why a detrimental process such as ageing would evolve, and why there is so much variability in the lifespans of organisms. The classical theories of evolution suggest that environmental factors, such as predation, accidents, disease, and/or starvation, ensure that most organisms living in natural settings will not live until old age, and so there will be very little pressure to conserve genetic changes that increase longevity. Natural selection will instead strongly favor genes which ensure early maturation and rapid reproduction, and the selection for genetic traits which promote molecular and cellular self-maintenance will decline with age for most organisms.
The will to live is a concept developed by the German philosopher Arthur Schopenhauer, representing an irrational "blind incessant impulse without knowledge" that drives instinctive behaviors, causing an endless insatiable striving in human existence.
Eusociality is the highest level of organization of sociality. It is defined by the following characteristics: cooperative brood care, overlapping generations within a colony of adults, and a division of labor into reproductive and non-reproductive groups. The division of labor creates specialized behavioral groups within an animal society which are sometimes referred to as 'castes'. Eusociality is distinguished from all other social systems because individuals of at least one caste usually lose the ability to perform behaviors characteristic of individuals in another caste. Eusocial colonies can be viewed as superorganisms.
In behavioral ecology, adaptive behavior is any behavior that contributes directly or indirectly to an individual's reproductive success, and is thus subject to the forces of natural selection. Examples include favoring kin in altruistic behaviors, sexual selection of the most fit mate, and defending a territory or harem from rivals.
Gravitaxis is a form of taxis characterized by the directional movement of an organism in response to gravity.
Human ethology is the study of human behavior. Ethology as a discipline is generally thought of as a sub-category of biology, though psychological theories have been developed based on ethological ideas. The bridging between biological sciences and social sciences creates an understanding of human ethology. The International Society for Human Ethology is dedicated to advancing the study and understanding of human ethology.
Microorganisms engage in a wide variety of social interactions, including cooperation. A cooperative behavior is one that benefits an individual other than the one performing the behavior. This article outlines the various forms of cooperative interactions seen in microbial systems, as well as the benefits that might have driven the evolution of these complex behaviors.
The theoretical foundations of evolutionary psychology are the general and specific scientific theories that explain the ultimate origins of psychological traits in terms of evolution. These theories originated with Charles Darwin's work, including his speculations about the evolutionary origins of social instincts in humans. Modern evolutionary psychology, however, is possible only because of advances in evolutionary theory in the 20th century.
Biological bet hedging occurs when organisms suffer decreased fitness in their typical conditions in exchange for increased fitness in stressful conditions. Biological bet hedging was originally proposed to explain the observation of a seed bank, or a reservoir of ungerminated seeds in the soil. For example, an annual plant's fitness is maximized for that year if all of its seeds germinate. However, if a drought occurs that kills germinated plants, but not ungerminated seeds, plants with seeds remaining in the seed bank will have a fitness advantage. Therefore, it can be advantageous for plants to "hedge their bets" in case of a drought by producing some seeds that germinate immediately and other seeds that lie dormant. Other examples of biological bet hedging include female multiple mating, foraging behavior in bumble bees, nutrient storage in rhizobia, and bacterial persistence in the presence of antibiotics.
Autogamy or self-fertilization refers to the fusion of two gametes that come from one individual. Autogamy is predominantly observed in the form of self-pollination, a reproductive mechanism employed by many flowering plants. However, species of protists have also been observed using autogamy as a means of reproduction. Flowering plants engage in autogamy regularly, while the protists that engage in autogamy only do so in stressful environments.
This glossary of genetics and evolutionary biology is a list of definitions of terms and concepts used in the study of genetics and evolutionary biology, as well as sub-disciplines and related fields, with an emphasis on classical genetics, quantitative genetics, population biology, phylogenetics, speciation, and systematics. Overlapping and related terms can be found in Glossary of cellular and molecular biology, Glossary of ecology, and Glossary of biology.