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Life
Life is a characteristic that distinguishes physical entities that have biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased (they have died), 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 ambiguous and may or may not define viruses, viroids, or potential synthetic life as “living”. Biology is the science concerned with the study of life.
The definition of life is controversial. The current definition is that organisms are open systems that maintain homeostasis, are composed of cells, have a life cycle, undergo metabolism, can grow, adapt to their environment, respond to stimuli, reproduce and evolve. However, several other biological definitions have been proposed, and there are some borderline cases of life, such as viruses or viroids. In the past, there have been many attempts to define what is meant by “life” through obsolete concepts such as odic force, hylomorphism, spontaneous generation and vitalism, that have now been disproved by biological discoveries. 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. 3.45 billion year old Australian rocks are reported to have contained microorganisms. In 2016, scientists reported identifying a set of 355 genes thought to be present in the last universal common ancestor (LUCA) of all living organisms, already a complex organism and not the first living thing.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. The cell is considered the structural and functional unit 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 speculate 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.
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Life (noun)
The living.
“Having experienced both, the vampire decided that he preferred (un)death to life.”
“He gave up on life.”
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Life (noun)
The animating principle or force that keeps an inorganic thing or concept metaphorically alive (dynamic, relevant, etc) and makes it a “living document”, “living constitution”, etc.
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Life (noun)
Lifeforms, generally or collectively.
“It’s life, but not as we know it.”
“She discovered plant life on the planet.”
“The rover discovered signs of life on the alien world.”
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Life (noun)
A living individual; the fact of a particular individual being alive. Chiefly when indicating individuals were lost (died) or saved.
“Many lives were lost during the war.”
“Her quick thinking saved many dogs’ lives.”
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Life (noun)
Existence.
“Man’s life on this planet has been marked by continual conflict.”
“the eternal life of the soul”
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Life (noun)
The status possessed by any of a number of entities, including animals, plants, fungi, bacteria, and sometimes viruses, which have the properties of replication and metabolism.
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Life (noun)
A worthwhile existence.
“He gets up early in the morning, works all day long — even on weekends — and hardly sees his family. That’s no life!”
“His life was ruined by drugs.”
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Life (noun)
A particular aspect of existence.
“He struggled to balance his family life, social life and work life.”
“sex life, political life”
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Life (noun)
Social life.
“Get a life.”
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Life (noun)
A period of time during which something has existence.
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Life (noun)
Something which is inherently part of a person’s existence, such as job, family, a loved one, etc.
“She’s my love, my life.”
“Running the bakery is her life.”
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Life (noun)
The period during which one (a person, an animal, a plant; a civilization, species; a star; etc) is alive.
“This light bulb is designed to have a life of 2,000 hours.”
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Life (noun)
The span of time during which an object operates.
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Life (noun)
The period of time during which an object is recognizable.
“The life of this milk carton may be thousands of years in this landfill.”
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Life (noun)
A particular phase or period of existence.
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Life (noun)
A period extending from a when a (positive or negative) office, punishment, etc is conferred on someone until that person dies (or, sometimes, reaches retirement age).
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Life (noun)
Animation; spirit; vivacity.
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Life (noun)
A life sentence; a period of imprisonment that lasts until the convict’s death (or, sometimes, parole).
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Life (noun)
A biography.
“His life of the founder is finished, except for the title.”
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Life (noun)
Nature, reality, and the forms that exist it.
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Life (noun)
An opportunity for existence.
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Life (noun)
The most lively component or participant.
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Life (noun)
One of the player’s chances to play, lost when the player’s character dies or when certain mistakes are made.
“Scoring 1000 points is rewarded with an extra life.”
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Life (noun)
The life insurance industry.
“I work in life.”
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Life (noun)
A life assured under a life assurance policy (equivalent to the policy itself for a single life contract).
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Live (verb)
To be alive; to have life.
“He’s not expected to live for more than a few months.”
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Live (verb)
To have permanent residence somewhere, to inhabit, to reside.
“I live at 2a Acacia Avenue.”
“He lives in LA, but he’s staying here over the summer.”
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Live (verb)
To survive; to persevere; to continue.
“Her memory lives in that song.”
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Live (verb)
To cope.
“You’ll just have to live with it!”
“I can’t live in a world without you.”
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Live (verb)
To pass life in a specified manner.
“It is difficult to live in poverty.”
“And they lived happily ever after.”
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Live (verb)
To spend, as one’s life; to pass; to maintain; to continue in, constantly or habitually.
“To live an idle or a useful life.”
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Live (verb)
To act habitually in conformity with; to practice; to exemplify in one’s way of life.
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Live (verb)
To outlast danger; to float (said of a ship, boat, etc).
“No ship could live in such a storm.”
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Live (verb)
To maintain or support one’s existence; to provide for oneself; to feed; to subsist.
“It is hard to live on the minimum wage.”
“They lived on stale bread.”
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Live (verb)
To make the most of life; to experience a full, rich life.
“I’m sick of spending every day studying at home: I want to go out there and live!”
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Live (adjective)
Having life; that is alive.
“The post office will not ship live animals.”
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Live (adjective)
Being in existence; actual
“He is a live example of the consequences of excessive drinking.”
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Live (adjective)
Having active properties; being energized.
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Live (adjective)
Operational; being in actual use rather than in testing.
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Live (adjective)
Taken from a living animal.
“live feathers”
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Live (adjective)
Imparting power; having motion.
“the live spindle of a lathe”
“a live, or driving, axle”
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Live (adjective)
Still in active play.
“a live ball”
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Live (adjective)
Seen or heard from a broadcast, as it happens.
“The station presented a live news program every evening.”
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Live (adjective)
Of a performance or speech, in person.
“This nightclub has a live band on weekends.”
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Live (adjective)
Of a recorded performance, made in front of an audience, or not having been edited after recording.
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Live (adjective)
Of firearms or explosives, capable of causing harm.
“The air force practices dropping live bombs on the uninhabited island.”
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Live (adjective)
Electrically charged or energized, usually indicating that the item may cause electrocution if touched.
“Use caution when working near live wires.”
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Live (adjective)
Being a bet which can be raised by the bettor, usually in reference to a blind or straddle.
“Tommy’s blind was live, so he was given the option to raise.”
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Live (adjective)
Featuring humans; not animated, in the phrases “live actors” or “live action”.
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Live (adjective)
Being in a state of ignition; burning.
“a live coal; live embers”
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Live (adjective)
Full of earnestness; active; wide awake; glowing.
“a live man, or orator”
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Live (adjective)
Vivid; bright.
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Live (adverb)
Of an event, as it happens; in real time; direct.
“The concert was broadcast live by radio.”
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Live (adverb)
Of making a performance or speech, in person.
“He’ll be appearing live at the auditorium.”
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Live (noun)
life
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Live (verb)
remain alive
“both cats lived to a ripe age”
“the doctors said she had only six months to live”
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Live (verb)
be alive at a specified time
“he lived four centuries ago”
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Live (verb)
spend one’s life in a particular way or under particular circumstances
“he was living a life of luxury in Australia”
“people are living in fear in the wake of the shootings”
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Live (verb)
(of an employee or student) reside at (or away from) the place where one works or studies
“the development is designed to provide extra accommodation for undergraduates to enable all 400 to live in”
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Live (verb)
supply oneself with the means of subsistence
“they live by hunting and fishing”
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Live (verb)
survive (an unpleasant experience or period)
“both men lived through the Depression”
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Live (verb)
survive in someone’s mind; be remembered
“only the name lived on”
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Live (verb)
have an exciting or fulfilling life
“he couldn’t wait to get out of school and really start living”
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Live (verb)
regard as the purpose or most important aspect of one’s life
“Tony lived for his painting”
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Live (verb)
(of a ship) escape destruction; remain afloat.
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Live (verb)
make one’s home in a particular place or with a particular person
“I’ve lived in the East End all my life”
“they lived with his grandparents”
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Live (verb)
(of an object) be kept in a particular place
“I told her where the coffee lived and went back to sleep”
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Live (adjective)
not dead or inanimate; living
“live animals”
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Live (adjective)
(of a vaccine) containing viruses or bacteria that are living but of a mild or attenuated strain.
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Live (adjective)
(of yogurt) containing the living microorganisms by which it is formed.
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Live (adjective)
relating to a musical performance given in concert, not on a recording
“there is traditional live music played most nights”
“a live album”
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Live (adjective)
(of a broadcast) transmitted at the time of occurrence, not from a recording
“live coverage of the match”
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Live (adjective)
(of a wire or device) connected to a source of electric current.
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Live (adjective)
of, containing, or using undetonated explosive
“live ammunition”
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Live (adjective)
(of coals) burning or glowing.
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Live (adjective)
(of a match) unused.
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Live (adjective)
(of a wheel or axle in machinery) moving or imparting motion.
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Live (adjective)
(of a ball in a game) in play, especially in contrast to being foul or out of bounds.
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Live (adjective)
(of a question or subject) of current or continuing interest and importance
“the future organization of Europe has become a live issue”
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Live (adverb)
as or at an actual event or performance
“the match will be televised live”