Life is a characteristic distinguishing physical entities having biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased, or because they never had such functions and are classified as inanimate. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. The criteria can at times be ambiguousand may or may not define viruses, viroids, or potential artificial life as "living". Biology is the primary science concerned with the study of life, although many other sciences are involved.
The definition of life is controversial. The current definition is that organisms maintain homeostasis, are composed of cells, undergo metabolism, can grow, adapt to their environment, respond to stimuli, and reproduce. However, many other biological definitions have been proposed, and there are some borderline cases of life, such as viruses. Throughout history, there have been many attempts to define what is meant by "life" and many theories on the properties and emergence of living things, such as materialism, the belief that everything is made out of matter and that life is merely a complex form of it; hylomorphism, the belief that all things are a combination of matter and form, and the form of a living thing is its soul; spontaneous generation, the belief that life repeatedly emerges from non-life; and vitalism, a now largely discredited hypothesis that living organisms possess a "life force" or "vital spark". Modern definitions are more complex, with input from a diversity of scientific disciplines. Biophysicists have proposed many definitions based on chemical systems; there are also some living systems theories, such as the Gaia hypothesis, the idea that the Earth itself is alive. Another theory is that life is the property of ecological systems, and yet another is elaborated in complex systems biology, a branch or subfield of mathematical biology. Abiogenesis describes the natural process of life arising from non-living matter, such as simple organic compounds. Properties common to all organisms include the need for certain core chemical elements to sustain biochemical functions. Life on Earth first appeared as early as 4.28 billion years ago, soon after ocean formation 4.41 billion years ago, and not long after the formation of the Earth 4.54 billion years ago.
Earth's current life may have descended from an RNA world, although RNA-based life may not have been the first. The mechanism by which life began on Earth is unknown, though many hypotheses have been formulated and are often based on the Miller–Urey experiment. The earliest known life forms are microfossils of bacteria. In July 2016, scientists reported identifying a set of 355 genes believed to be present in the last universal common ancestor (LUCA) of all living organisms. Since its primordial beginnings, life on Earth has changed its environment on a geologic time scale. To survive in most ecosystems, life must often adapt to a wide range of conditions. Some microorganisms, called extremophiles, thrive in physically or geochemically extreme environments that are detrimental to most other life on Earth. Aristotle was the first person to classify organisms. Later, Carl Linnaeus introduced his system of binomial nomenclature for the classification of species .
Eventually new groups and categories of life were discovered, such as cells and microorganisms, forcing dramatic revisions of the structure of relationships between living organisms. Cells are sometimes considered the smallest units and "building blocks" of life. There are two kinds of cells, prokaryotic and eukaryotic, both of which consist of cytoplasm enclosed within a membrane and contain many biomolecules such as proteins and nucleic acids. Cells reproduce through a process of cell division, in which the parent cell divides into two or more daughter cells. Though currently only known on Earth, life need not be restricted to it, and many scientists believe in the existence of extraterrestrial life. Artificial life is a computer simulation or man-made reconstruction of any aspect of life, which is often used to examine systems related to natural life. Death is the permanent termination of all biological functions which sustain an organism, and as such, is the end of its life. Extinction is the process by which an entire group or taxon, normally a species, dies out. Fossils are the preserved remains or traces of organisms.
Motivation is a theoretical construct used to explain behaviour. It gives the reason for people's actions, desires, and needs. Motivation can also be defined as one's direction to behavior, or what causes a person to want to repeat a behavior and vice versa. A motive is what prompts the person to act in a certain way, or at least develop an inclination for specific behavior. According to Maehr and Meyer, "Motivation is a word that is part of the popular culture as few other psychological concepts are."
Motivation as a desire to perform an action is usually defined as having two parts, directional such as directed towards a positive stimulus or away from a negative one, as well as the activated "seeking phase" and consummatory "liking phase". This type of motivation has neurobiological roots in the basal ganglia, and mesolimbic dopaminergic pathways.
Activated "seeking" behavior, such as locomotor activity is influenced by dopaminergic drugs, and in micro dialysis reveals dopamine release during anticipation of a reward. The "wanting behavior" associated with a rewarding stimulus can be increased by microinjections of dopamine and dopaminergic drugs in the dorsorostral nucleus accumbens and posterior ventral palladium. Opioid injections in this area produce pleasure, however outside of these hedonic hotspots they create an increased desire. Furthermore, depletion or inhibition of DA in neurons of the nucleus accumbens decreases appetitive but not consummatory behavior. Dopamine is further implicated in motivation as administration of amphetamine increased the break point in a progressive ratio self-reinforcement schedule. That is, subjects were willing to go to greater lengths (e.g. press a level more times) to obtain a reward.
An attitude can be as a positive or negative evaluation of people, objects, events, activities, and ideas. It could be concrete, abstract or just about anything in your environment, but there is a debate about precise definitions. Eagly and Chaiken, for example, define an attitude as "a psychological tendency that is expressed by evaluating a particular entity with some degree of favor or disfavor.
Though it is sometimes common to define an attitude as affect toward an object, affect (i.e., discrete emotions or overall arousal) is generally understood to be distinct from attitude as a measure of favorability. Attitude may influence the attention to attitude objects, the use of categories for encoding information and the interpretation, judgement and recall of attitude-relevant information. These influences tend to be more powerful for strong attitudes which are easily accessible and based an elaborate knowledge structure. Attitudes may guide attention and encoding automatically, even if the individual is pursuing unrelated goals.
Success denotes the achievement of aims or attainment of goals or social status. It is often used specifically to mean financial profitability. People who achieve their goals are frequently termed "successes".
Achievement of an action within a specified period of time or within a specified parameter. Success can also mean completing an objective or reaching a goal. Success can be expanded to encompass an entire project or be restricted to a single component of a project or task. It can be achieved within the workplace, or in an individual's personal life. For example, if an individual's personal goal is to be accepted in a new career, success would occur after the individual has been officially accepted into his or her new place of employment.
Colloquial term used to describe a person that has achieved his or her personal, financial or career goals.
It could also be used to describe an individual that has more objects (money or any other desirable item) relative to another individual. For example, a professional athlete can be called "a success."
"If You dont know how tolive,why wonder about death? In heaven,all the intresting pwoplw are missing.I'm the one that has to die when its time for me to die, so let me live my life,the way i want to...life and death are one thread ,the same line viewed from different sides.I learned that courage was not the absence of fear ,but the triumph over it. Thebrave man is not he who does not feel afraid ,but he who conquers that fear"
Death anxiety is the morbid, abnormal, or persistent fear of one's own death. One source defines death anxiety as a "feeling of dread, apprehension or solicitude (anxiety) when one thinks of the process of dying, or ceasing to ‘be’". It is also referred to as thanatophobia (fear of death), and is distinguished from necrophobia, which is a specific fear of dead or dying persons and/or things (i.e. others who are dead or dying, not one's own death or dying). Lower ego integrity, increased numbers of physical problems, and more psychological problems are predictive of higher levels of death anxiety in elderly people.
Fear is a feeling induced by perceived danger or threat that occurs in certain types of organisms, which causes a change in metabolic and organ functions and ultimately a change in behavior, such as fleeing, hiding, or freezing from perceived traumatic events. Fear in human beings may occur in response to a specific stimulus occurring in the present, or in anticipation or expectation of a future threat perceived as a risk to body or life.
The fear response arises from the perception of danger leading to confrontation with or escape from/avoiding the threat (also known as the fight-or-flight response), which in extreme cases of fear (horror and terror) can be a freeze response or paralysis.
In humans and animals, fear is modulated by the process of cognition and learning. Thus fear is judged as rational or appropriate and irrational or inappropriate. An irrational fear is called a phobia. Psychologists such as John B. Watson, Robert Plutchik, and Paul Ekman have suggested that there is only a small set of basic or innate emotions and that fear is one of them. This hypothesized set includes such emotions as acute stress reaction, anger, angst, anxiety, fright, horror, joy, panic, and sadness. Fear is closely related to, but should be distinguished from, the emotion anxiety, which occurs as the result of threats that are perceived to be uncontrollable or unavoidable. The fear response serves survival by generating appropriate behavioral responses, so it has been preserved throughout evolution.