What is the word of life definition

Asking a biologist to define ‘life’ is a bit like looking-up the word ‘definition’ in a dictionary — it’s as if you’re questioning their very existence.

Biologists like myself don’t agree on what life actually is, in no small part because definitions don’t encompass its diversity, especially at the edges.

One of my favorite science writers, Carl Zimmer, has just published a book entitled Life’s Edge: The Search for What it Means to be Alive, along with an excerpt on the frustrated efforts to develop a universal definition of life.

I’ll discuss the new book below, but given that my article on the challenge of defining life is now two years old, let’s first revisit the fundamental issues.

Scientific criteria

For centuries, scientists and philosophers have proposed hundreds of definitions of life. None have been widely accepted.

In 2011, biophysicist Edward Trifonov tried to find consensus among 123 definitions by grouping the words they contained into clusters that had similar meanings. He then combined the most-frequently used word from each cluster to produce a ‘minimal’ definition: Life is self-reproduction with variation.

One criticism of Trifonov’s definition is that it defines life as the outcome of replication and mutation, two processes that create the variety that lets nature ‘select’ which individuals live long enough to reproduce. It’s therefore missing evolution by natural selection (adaptation or ‘survival of the fittest’) — the vital process that enables a population of organisms to adapt to an ever-changing environment.

Another problem with a concise or minimal definition is that it’s easy to come up with exceptions. A computer virus can also copy itself and mutate, for example, while some organisms reproduce by making clones that are genetically identical.

Textbooks traditionally describe life with a list consisting of two kinds of essential features (properties): physical characteristics such as cells and DNA — what life has — and processes like growth and reproduction — what life does.

But, as with Trifonov’s definition, the trouble with such a list definition is that you can easily think of numerous counter-examples that don’t meet all the so-called essential criteria.

Some biologists don’t believe that a virus is alive because it can’t reproduce outside a host cell, for example. My argument against such belief is that we all accept that a bacterium is alive, and yet parasitic bacteria like Coxiella burnetii can’t live independently either — they’re obligate intracellular parasites.

And that’s just life as we know it, here on Earth. If you’re searching for life on other planets, you have to drop almost every item from a list — including cells and growth — as you obviously can’t see such features from trillions of kilometres (light-years) away.

As a consequence, astrobiologists ignore terrestrial signs of life and instead try to detect ‘biosignatures’ — objects, substances or patterns that could have been produced by extraterrestrial life-forms.

For life that’s even more alien, on our world or elsewhere, you enter the realm of science-fiction, such as artificial intelligence (AI) in form of characters like Data from Star Trek.

Philosophical arguments

The excerpt from Life’s Edge mentions that asking ‘What is life?’ can be compared to asking another question that’s hard to answer: ‘What are games?’

That comparison is from a philosophical concept devised by Ludwig Wittgenstein, who claimed that some things don’t have a single feature that’s common to all, but overall they share a whole series of features, a kind of ‘family resemblance’.

Inspired by Wittgenstein, a multidisciplinary team at Lund University in Sweden (mostly philosophers, theologians and other non-biologists) compiled a selection of various things — everything from animals and plants to viruses and snowflakes — and a list of features associated with living things, such as DNA and metabolism.

The Lund team then carried out a survey of scholars, asking the participants to tick boxes on a checklist of (what they considered relevant) features for each thing. The study used statistical clustering to group ‘families’ of things sharing common features, which grouped mice, birds and other animals with a brain together, while the brainless plants and bacteria were in a different cluster.

Any decent biologist wouldn’t be surprised by those results, and might add that the approach was naive. The mistake the Lund team made is that most people look at the natural world with a human-obsessed, ‘anthropocentric’ perspective. That explains why the things that most resemble us, with brains, clustered together.

The approach was biased by the initial choice of features. Take the SARS-CoV-2 coronavirus, say, which has RNA (not DNA) for its genetic material: if viruses could send surveys to one another, the study’s results would have been very different.

Zimmer’s new book also includes a profile of philosopher Carol Cleland, who has published dozens of papers on detecting or defining life, as well as a 2019 book called The Quest for a Universal Theory of Life.

At one 2001 meeting, Cleland told an audience dominated by scientists that «the whole definition project was worthless.» Zimmer paints her as a lone radical, but Cleland isn’t alone in her opinion that definitions are a waste of time.

In 2011, philosopher Edouard Machery used a Venn diagram of features to try and identify overlap between a hypothetical evolutionary biologist, an astrobiologist and an AI researcher. Machery concluded that «the project of defining life is either impossible or pointless.»

According to Cleland, «Definitions are not the proper tools for answering the scientific question ‘What is life?'» Note that she specifically says scientific, which I take to mean definitions used in science, like a working definition that astrobiologists might use so that everyone’s on the same page when searching for alien biosignatures.

The scientist in me mostly agrees with Cleland’s philosophical position but, as a science communicator, I also think there’s another important factor to consider.

Public understanding

Imagine that a child is just discovering nature and asks their parent or teacher «What is life?» Responding with «Defining life is pointless and worthless» would not only make you kind of an asshole, it might also kill the kid’s curiosity. Better to give them a clear statement first, then add caveats to encourage further investigation later.

While some philosophers don’t want a universal definition and many scientists don’t really need one, there’s a third group of people who do need a definition of life: the general public.

For the public, the question of ‘What is life?’ revolves around language and the meaning of words — it’s a semantic issue. The semantics aren’t trivial either.

Dictionary definitions are wrong because they send people round in circles. A dictionary will use words like ‘organisms’, so a statement’s logic is circular (a tautology) because it uses an example of life to define life, which is ridiculous.

The public needs a folk definition — one that’s mostly right and makes intuitive sense but removes the logical circularity found in dictionaries.

I’d love to see a linguist produce a sentence that works. Until then, I’d humbly suggest using my ‘popular definition’: Life is an entity with the ability to adapt to its environment.

If you think you have a better one, direct it to me on Twitter (@jvchamary). Just don’t ask me for a biologist’s definition.

In 2019 they set out to find it by carrying out a survey of scientists and other scholars. They put together a list of things including people, chickens, Amazon mollies, bacteria, viruses, snowflakes, and the like. Next to each entry the Lund team provided a set of terms commonly used to talk about living things, such as order, DNA, and metabolism.

The participants in the study checked off all the terms that they believed to apply to each thing. Snowflakes have order, for example, but they don’t have a metabolism. A human red blood cell has a metabolism but it contains no DNA.

The Lund researchers used a statistical technique called cluster analysis to look at the results and group the things together based on family resemblances. We humans fell into a group with chickens, mice, and frogs — in other words, animals with brains. Amazon mollies have brains, too, but the cluster analysis put them in a separate group close to our own. Because they don’t reproduce by themselves, they’re set a little apart from us. Further away, the scientists found a cluster made up of brainless things, such as plants and free‐living bacteria. In a third group was a cluster of red blood cells and other cell‐like things that can’t live on their own.

Furthest away from us were things that are commonly not considered alive. One cluster included viruses and prions, which are deformed proteins that can force other proteins to take their shape. Another included snowflakes, clay crystals, and other things that don’t replicate in a lifelike way.

The Lund researchers found that they could sort things pretty well into the living and the nonliving without getting tied up in an argument over the perfect definition of life. They propose that we can call something alive if it has a number of properties that are associated with being alive. It doesn’t have to have all those properties, nor does it even need exactly the same set found in any other living thing. Family resemblances are enough.

One philosopher has taken a far more radical stand. Carol Cleland argues that there’s no point in searching for a definition of life or even just a convenient stand‐in for one. It’s actually bad for science, she maintains, because it keeps us from reaching a deeper understanding about what it means to be alive. Cleland’s contempt for definitions is so profound that some of her fellow philosophers have taken issue with her. Kelly Smith has called Cleland’s ideas “dangerous.”

Cleland had a slow evolution into a firebrand. When she enrolled in the University of California, Santa Barbara, she started off studying physics. “I was a klutz in the lab, and my experiments never turned out right,” she later told an interviewer. From physics she turned to geology, and while she liked the wild places that the research took her to, she didn’t like feeling isolated as a woman in the male‐dominated field. She discovered philosophy in her junior year and was soon grappling with deep questions about logic. After graduating college and spending a year working as a software engineer, she went to Brown University to earn a Ph.D. in philosophy.

In graduate school Cleland mulled space and time, cause and effect.

When Cleland finished grad school, she moved on to subjects that were easier to talk about at dinner parties. She worked at Stanford University for a time, contemplating the logic of computer programs. She then became an assistant professor at the University of Colorado, where she remained for the rest of her career.

In Boulder, Cleland turned her attention to the nature of science itself. She examined how some scientists, like physicists, could run experiments over and over again, while others, like geologists, couldn’t replay millions of years of history. It was while she was reflecting about these differences that she learned about a Martian rock in Antarctica that was posing a philosophical conundrum of its own.

[The Martian rock, a meteorite designated Allan Hills 84001, was examined in 1996 by a NASA team led by David McKay. They reported seeing signs of ancient life in it, including microbial fossils, but most scientists dismissed the evidence as too ambiguous to be credible.]

A lot of the arguments over Allan Hills 84001 had less to do with the rock itself than with the right way to do science. Some researchers thought the NASA team had done an admirable job of studying it, but others thought it was ridiculous to conclude from their findings that the meteorite might contain fossils. The planetary scientist Bruce Jakosky, one of Cleland’s colleagues at the University of Colorado, decided to organize a public discussion where the two sides could air their views. But he realized that judging Allan Hills 84001 required more than running some experiments to measure magnetic minerals. It demanded thinking through how we make scientific judgments. He asked Cleland to join the event, to talk about Allan Hills 84001 as a philosopher.

What started as a quick prep for a talk turned into a dive into the philosophy of extraterrestrial life. Cleland concluded that the fight over Allan Hills 84001 sprang from the divide between experimental and historical sciences. The critics made the mistake of treating the meteorite study as experimental science. It was absurd to expect McKay’s team to replay history. They couldn’t fossilize microbes on Mars for 4 billion years and see if they matched Allan Hills 84001. They couldn’t hurl a thousand asteroids at a thousand copies of Mars and see what came our way.

Cleland concluded that the NASA team had carried out good historical science, comparing explanations for the ones that explained their evidence best. “The martian‐life hypothesis is a very good candidate for being the best explanation of the structural and chemical features of the martian meteorite,” she wrote in 1997 in the Planetary Report.

Cleland’s work on the meteorite impressed Jakosky so much that he invited her in 1998 to join one of the teams at NASA’s newly created Astrobiology Institute. In the years that followed, Cleland developed a philosophical argument for what the science of astrobiology should look like. She informed her ideas by spending time with scientists doing different kinds of research that fit under the umbrella of astrobiology. She traveled around the Australian outback with a paleontologist searching for clues to how giant mammals went extinct 40,000 years ago. She went to Spain to learn how geneticists sequence DNA. And she spent a lot of time at scientific meetings, roaming from talk to talk. “I felt like a kid in a candy store,” she once told me.

But sometimes the scientists Cleland spent time with set off her philosophical alarms. “Everybody was working with a definition of life,” she recalled. NASA’s definition, only a few years old at that point, was especially popular.

As a philosopher, Cleland recognized that the scientists were making a mistake. Their error didn’t have to do with determinate attributes or some other fine philosophical point understood only by a few logicians. It was a fundamental blunder that got in the way of the science itself. Cleland laid out the nature of this mistake in a paper, and in 2001 she traveled to Washington, D.C., to deliver it at a meeting of the American Association for the Advancement of Science. She stood up before an audience made up mostly of scientists, and told them it was pointless to try to find a definition of life.

“There was an explosion,” Cleland recalled. “Everyone was yelling at me. It was really amazing. Everyone had their pet definitions and wanted to air them. And here I told them the whole definition project was worthless.”

Fortunately, some people who heard Cleland talk thought she was onto something. She began collaborating with astrobiologists to explore the implications of her ideas. Over the course of two decades she published a series of papers, culminating in a book, The Quest for a Universal Theory of Life.

The trouble that scientists had with defining life had nothing to do with the particulars of life’s hallmarks such as homeostasis or evolution. It had to do with the nature of definitions themselves — something that scientists rarely stopped to consider. “Definitions,” Cleland wrote, “are not the proper tools for answering the scientific question ‘what is life?’”

Definitions serve to organize our concepts. The definition of, say, a bachelor is straightforward: an unmarried man. If you’re a man and you’re unmarried, you are — by definition — a bachelor. Being a man is not enough to make you a bachelor, nor is being unmarried. As for what it means to be a man, well, that can get complicated. And marriage has its own complexity. But we can define “bachelor” without getting bogged down in those messy matters. The word simply links these concepts in a precise way. And because definitions have such a narrow job to do, we can’t revise them through scientific investigation. There is simply no way that we could ever discover that we were wrong about the definition of a bachelor as being an unmarried man.

Life is different. It is not the sort of thing that can be defined simply by linking together concepts. As a result, it’s futile to search for a laundry list of features that will turn out to be the real definition of life. “We don’t want to know what the word life means to us,” Cleland said. “We want to know what life is.” And if we want to satisfy our desire, Cleland argues, we need to give up our search for a definition.

From the book Life’s Edge: The Search for What It Means to Be Alive by Carl Zimmer, published by Dutton, an imprint of Penguin Publishing Group, a division of Penguin Random House LLC. Copyright © 2021 by Carl Zimmer.

by Brian Shilhavy

Life. It is one of the most common words in the English language. It is something to “live,” something to “spend,” something that begins and ends, something that is evaluated as “good” or “bad,” as “healthy” or “unhealthy.”

But how do we actually define it? Is it defined by our culture, or does it have an intrinsic meaning that transcends how the culture uses the word?

How you understand or define “life” affects pretty much everything you do, and I doubt that very many people have actually spent time evaluating their understanding of “life,” but passively just accept how the culture defines it.

“Life” is closely associated with “truth,” which means that the meaning of “life” is not dependent on people’s opinions or understanding of what it is.

It just is. It transcends even language, therefore it requires that we examine the language we use to describe and define life, and the closer we can come to its actual intrinsic meaning, the closer we come to understanding “truth.”

To help you decide whether or not you want to continue reading this article, I need to repeat my working premises that I have publicly explained in previous articles, and which are the premises I have accepted as true and are the foundation for all the articles I have personally written and published on Health Impact News for the past 12 years, which is that the Ancient writings of the Bible, also referred to as the “Scriptures,” are true in so much as they contain truth.

They are not the total embodiment of truth, as that originates from God (Yahweh/Jehovah) and his Son Jesus Christ, who is the “living Word of God.”

So for example, one of the “truths” found in the Scriptures is: Love your neighbor as yourself. This is written in English, so to properly understand this truth, we need to define “love” and “neighbor,” which is generally defined by our culture and language. It is also an “imperative” (command) truth.

But even if we come to an agreement on how these English words are defined so that we can properly communicate with each other about this truth so that we generally agree on how these words/concepts are defined, the truth of how that works out in your life, or mine, is not something we can find in the Scriptures.

Who I am supposed to be loving as my neighbor, will not usually be the same as who you are supposed to be loving as your neighbor, especially if we do not even know each other.

The general principle of this truth, “love your neighbor as yourself,” is always true, but how that truth is applied to someone’s life or situation is not the same for everyone.

And the knowledge of that kind of truth does not come from words written in a book, even if those words are true. They come from a relationship with the Living Word of God.

But that’s a topic for another article.

Where does Life Come From?

This is a question that is easily answered in the Scriptures, but when we closely examine just what the English word “life” means, it actually becomes more complicated.

As I have stated in other articles I have written, I have been studying the Bible for over 40 years, and I start each day by reading it and studying it.

I recently was reading through Paul’s two letters to his young associate, Timothy, and I recently wrote an article on what I found to be the main truth in Paul’s second letter to Timothy, and how that truth can be applied to us today. See:

Has Everyone Left You Because You are not Ashamed to Speak the Truth? Stay the Course!

But I came across something Paul wrote towards the end of his first letter to Timothy that Paul mentioned as an “aside.” In other words, it was not the main point he was making, but he stated it as a generally accepted fact.

I command you before God, who gives life to all things, and before Christ Jesus, who before Pontius Pilate testified the good confession, that you keep the commandment without spot, blameless, until the appearing of our Lord Jesus Christ; which in its own times he will show, who is the blessed and only Ruler, the King of kings, and Lord of lords; who alone has immortality, dwelling in unapproachable light; whom no man has seen, nor can see: to whom be honor and eternal power. Amen. (1 Timothy 6:13-16)

The “aside” here is the text I highlighted “who gives life to all things.”

I jotted down a note about this verse, and I thought to myself, “This would be a good topic for an article.”

I am familiar with this statement, and it is stated in many other places in the Scriptures, so I thought it would be a quick and easy article to write.

But as I dug deeper into the Greek words that are used in the New Testament which we translate as “life,” I soon learned that I did not understand this concept nearly as much as I thought I did, and so even though this would have been the earlier article I would have published before the one on 2 Timothy, I have now spent very many hours and days studying “life” as it is defined in the Scriptures, and I almost abandoned writing this article, so deep is the topic, and so inadequate do I feel in even attempting to write this article.

So I will be the first one to admit that I still have more to learn, but so important is this topic of “life,” that I felt I had to share what I have learned so far, as we are in desperate need today to identify the truth in our culture, and identify the lies, and it begins, in my opinion, with the proper understanding of “life.”

But before I start in examining the Greek words used by the New Testament writers that are translated into our English Bibles as “life,” let me give you other passages that confirm the truth Paul expressed here: God gives life to all things.

One of the most comprehensive statements of this truth is in Paul’s letter to the Colossians where he explains that Jesus Christ, in his pre-incarnate state, which means before he took on human form and was born to the virgin Mary, was the one who created everything in the universe.

He is the image of the invisible God, the firstborn over all creation.

For by him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things were created by him and for him. He is before all things, and in him all things hold together. (Colossians 1:15-17)

Here is the same truth again written in Paul’s first letter to the Corinthians:

For even if there are so-called gods, whether in heaven or on earth (as indeed there are many “gods” and many “lords”), yet for us there is but one God, the Father, from whom all things came and for whom we live; and there is but one Lord, Jesus Christ, through whom all things came and through whom we live. (1 Corinthians 8:5-6)

Here is the apostle John writing the same truth:

In the beginning was the Word, and the Word was with God, and the Word was God. He was with God in the beginning. Through him all things were made; without him nothing was made that has been made. In him was life, and that life was the light of men. (John 1:1-4)

Here is the same truth being stated in the book of Hebrews:

In the past God spoke to our forefathers through the prophets at many times and in various ways, but in these last days he has spoken to us by his Son, whom he appointed heir of all things, and through whom he made the universe.

The Son is the radiance of God’s glory and the exact representation of his being, sustaining all things by his powerful word. After he had provided purification for sins, he sat down at the right hand of the Majesty in heaven. (Hebrews 1:1-3)

I realize that the English word “life” is not in all of these verses, but I believe the truth that God gives life to all things is included in these passages as well.

Because God’s creative actions also include things that are not “alive,” such as the elements of the earth.

Genesis, the first book of the Bible, teaches us that God took some of these elements that we would not say were “alive” but then formed them into a living being, the first man.

The LORD God formed the man from the dust of the ground and breathed into his nostrils the breath of life, and the man became a living being. (Genesis 2:7)

So we can conclusively say that the Bible clearly teaches that ALL life comes from God, specifically from the person Jesus Christ. So now we just need to define what this “life” is.

What is “Life?”

The English noun life, and its corresponding verb, to live, along with other cognates of this word, such as alive, lively, lifeless, etc., have multiple meanings, and we generally understand the meaning the speaker or author is using by its context.

“Live,” for example, can be a noun or a verb based on usage. So “Live your life to its fullest” has a different meaning from “It’s being broadcast live,” for example. In written English we determine the meaning by context, but in spoken English the pronunciation is different based on usage, making it easier to distinguish.

This is true in Koine Greek also, but when we get to the usage of the English word life in the New Testament portion of the Bible, there is actually more than one word in the Greek that is translated into this single word in the English. And of those words in the Greek, which are mainly 3 different words, each of those words can have multiple meanings as well, based on the context in which it is being used, just like the English word group.

The primary 3 words in the Greek that are translated (sometimes) by the English word life, are ζωή (zóé), ψυχή (psuché), and βίος (bios).

Zóé and its cognates are by far the most common words translated to the English life, and it is found in all 27 books of the New Testament.

Psuché is the second most common, used hundreds of times including its cognates.

Bios is the least common (this actually surprised me), and is only used 11 times in the entire New Testament.

Zoe is almost always translated into the English word “life.” I surveyed a few English translations, and the only exception I found was in the older King James Version in Luke 16:25, where it is translated “lifetime,” which restricts its meaning to the duration of our physical lives in our natural body between our physical birth and our physical death.

Here is a verse where Jesus uses the word that seems to refer to our “life” between physical birth and physical death:

Then he said to them, “Watch out! Be on your guard against all kinds of greed; a man’s life does not consist in the abundance of his possessions.” (Luke 12:15)

Here is an example of Paul using it the same way:

If only for this life we have hope in Christ, we are to be pitied more than all men. (1 Corinthians 15:19)

As with the English word “life,” zoe has different variations of meanings, and besides “lifetime” can refer to the “natural life” that applies to humans, animals, and plants, but is also used with “eternal life” as exceeding the “life” of just our natural bodies, but including our “soul” and “spirit” which are not confined to just the existence of our physical bodies.

This concept of “eternal life” is, by far, the more common meaning found in the New Testament, referring to “life” as an eternal existence not confined to the duration of time we spend in our physical bodies. Some examples (note, in some of these verses the verb form, zao, is also being used):

“Then they will go away to eternal punishment, but the righteous to eternal life.” (Matthew 25:46)

Just as Moses lifted up the snake in the desert, so the Son of Man must be lifted up, that everyone who believes in him may have eternal life. For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. (John 3:14-16)

Jesus answered, “Everyone who drinks this water will be thirsty again, but whoever drinks the water I give him will never thirst. Indeed, the water I give him will become in him a spring of water welling up to eternal life.” (John 4:13-14)

“I tell you the truth, whoever hears my word and believes him who sent me has eternal life and will not be condemned; he has crossed over from death to life. I tell you the truth, a time is coming and has now come when the dead will hear the voice of the Son of God and those who hear will live. For as the Father has life in himself, so he has granted the Son to have life in himself. (John 5:24-26)

In the context of the New Testament writings, zoe also is used with “new life” to describe the spiritual rebirth found only in Jesus Christ, the first man resurrected from the (physical) dead which added new meaning to zoe that the ancient Greek philosophers writing in Classical Greek, such as Plato and Aristotle, did not have.

Jesus said to them, “I tell you the truth, it is not Moses who has given you the bread from heaven, but it is my Father who gives you the true bread from heaven. For the bread of God is he who comes down from heaven and gives life to the world.” “Sir,” they said, “from now on give us this bread.” Then Jesus declared, “I am the bread of life. He who comes to me will never go hungry, and he who believes in me will never be thirsty. (John 6:32-35)

Jesus said to her, “I am the resurrection and the life. He who believes in me will live, even though he dies; and whoever lives and believes in me will never die. Do you believe this?” (John 11:25-26)

We always carry around in our body the death of Jesus, so that the life of Jesus may also be revealed in our body. For we who are alive are always being given over to death for Jesus’ sake, so that his life may be revealed in our mortal body. (2 Corinthians 4:10-11)

For while we are in this tent, we groan and are burdened, because we do not wish to be unclothed but to be clothed with our heavenly dwelling, so that what is mortal may be swallowed up by life. (2 Corinthians 5:4)

The quality of this “life” is often associated with “light” and “truth” shining into the domain of Satan, exposing his lies hidden in the dark.

In the beginning was the Word, and the Word was with God, and the Word was God. He was with God in the beginning. Through him all things were made; without him nothing was made that has been made. In him was life, and that life was the light of men. The light shines in the darkness, but the darkness has not understood it. (John 1:1-5)

When Jesus spoke again to the people, he said, “I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life.” (John 8:12)

Psuché, on the other hand, is translated into English as “soul” about as often as it is translated into English as “life,” and refers to more than just our physical bodies. This Greek word is behind our modern English words like psyche, psychology, etc.

Here are some of the verses where psuche is translated as either “life” or “soul” in English:

Therefore I tell you, do not worry about your life, what you will eat or drink; or about your body, what you will wear. Is not  life more important than food, and the body more important than clothes? (Matthew 6:25)

Then Jesus asked them, “Which is lawful on the Sabbath: to do good or to do evil, to save life or to kill?” But they remained silent. (Mark 3:4)

Do not be afraid of those who kill the body but cannot kill the soul. Rather, be afraid of the One who can destroy both soul and body in hell. (Matthew 10:28)

Take my yoke upon you and learn from me, for I am gentle and humble in heart, and you will find rest for your souls. (Matthew 11:29)

Here the same word is translated “life” in one verse, and then the exact same word (psuche) in the following verse is translated “soul”:

For whoever wants to save his life will lose it, but whoever loses his life for me will find it. What good will it be for a man if he gains the whole world, yet forfeits his soul? Or what can a man give in exchange for his soul? (Matthew 16:25-26)

Another word used in English to translate psuche sometimes is “mind.”

But the Jews who refused to believe stirred up the Gentiles and poisoned their minds against the brothers. (Acts 14:2)

In some verses, psuche is translated into the English word “heart.”

Obey them not only to win their favor when their eye is on you, but like slaves of Christ, doing the will of God from your heart. (Ephesians 6:6)

Consider him who endured such opposition from sinful men, so that you will not grow weary and lose heart. (Hebrews 12:3)

As should be obvious from just this brief look at the various uses of the two most common Greek words in the New Testament portion of the Bible that are translated into the English word “life,” it has a much broader meaning than its usage in modern Western culture today, which over-emphasizes only our physical life starting with physical birth and ending with physical death.

In the New Testament writings, “life” cannot be understood apart from Jesus Christ, who broke the power of physical death and instituted “eternal life” in heaven, the Kingdom of God, which also exists on the physical earth at this time in the spiritual realm, invading the Kingdom of Satan, the current world system, also referred to as “darkness.”

So using zoe, we come back to that famous statement made by Jesus Christ in John 14:6:

Jesus answered, “I am the way and the truth and the life. No one comes to the Father except through me.” (John 14:6)

Jesus did not just explain what “life” is, he claimed that he IS “life.” And this truth fits with what was written in the passage in Colossians I quoted above:

For by him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things were created by him and for him. He is before all things, and in him all things hold together.

And he is the head of the body, the assembly; he is the beginning and the firstborn from among the dead, so that in everything he might have the supremacy.

For God was pleased to have all his fullness dwell in him, and through him to reconcile to himself all things, whether things on earth or things in heaven, by making peace through his blood, shed on the cross. (Colossians 1:16-20)

Jesus also used an analogy of a vine, a living plant, and the “branches” that lived off of the vine, but which “died” and were burned up once they were cut off from the vine, to illustrate how he IS the “life”:

I am the true vine, and my Father is the gardener. He cuts off every branch in me that bears no fruit, while every branch that does bear fruit he prunes so that it will be even more fruitful.

You are already clean because of the word I have spoken to you. Remain in me, and I will remain in you. No branch can bear fruit by itself; it must remain in the vine.

Neither can you bear fruit unless you remain in me. I am the vine; you are the branches. If a man remains in me and I in him, he will bear much fruit; apart from me you can do nothing.

If anyone does not remain in me, he is like a branch that is thrown away and withers; such branches are picked up, thrown into the fire and burned. (John 15:1-6)

Bios

But there is a 3rd Greek word that is sometimes translated “life” in the English translations of the Bible: bios. This noun is only used 11 times in the New Testament, and once in its verb form.

Notice how it is translated into English in each of these verses.

And he called his disciples to him and said to them, “Truly, I say to you, this poor widow has put in more than all those who are contributing to the offering box. For they all contributed out of their abundance, but she out of her poverty has put in everything she had, all she had to live on.” (Mark 12:43-44)

And as for what fell among the thorns, they are those who hear, but as they go on their way they are choked by the cares and riches and pleasures of life, and their fruit does not mature. (Luke 8:14)

And there was a woman who had had a discharge of blood for twelve years, and though she had spent all her living on physicians, she could not be healed by anyone. (Luke 8:43)

And the younger of them said to his father, ‘Father, give me the share of property that is coming to me.’ And he divided his property between them. (Luke 15:12)

But when this son of yours came, who has devoured your property with prostitutes, you killed the fattened calf for him!’ (Luke 15:30)

No soldier gets entangled in civilian pursuits, since his aim is to please the one who enlisted him. (2 Timothy 2:4 – note: some English translations say “every day life” or “affairs of life” for “bios” here.)

1 Peter 4:2-3 uses the verb form (only occurrence in the New Testament) in verse 2, and the noun in verse 3.

that you no longer should live the rest of your time in the flesh for the lusts of men, but for the will of God. For we have spent enough of our past time doing the desire of the Gentiles, and having walked in lewdness, lusts, drunken binges, orgies, carousings, and abominable idolatries. (1 Peter 4:2-3)

For all that is in the world, the lust of the flesh, the lust of the eyes, and the pride of life, isn’t the Father’s, but is the world’s. (1 John 2:16)

But whoever has the world’s goods, and sees his brother in need, and closes his heart of compassion against him, how does God’s love remain in him? (1 John 3:17)

I think it is easy to see by observing how bios is used in these verses that this is a very different, and mostly negative, term that is sometimes translated into “life” in English.

It is obviously only dealing with physical life, and the duration of that life between our physical birth and our physical death. It includes the things that “empower” our physical life, such as finances and worldly possessions, but also the emotions and desires that are tied into the physical world and the current world system ruled by Satan, such as pride, lust, idolatry, etc.

So even though bios is the original Greek word used the least amount of time in the New Testament, is it any surprise that of the three Greek words used to translate into “life,” that bios is the one most often used today in English and Western Culture?

We are familiar with the common English words derived from bios, such as biology, biologist, etc., which are used in academic settings in the study of “life.”

The English word “life” comes originally from the Germanic languages, the language group from where English originated.

Old English life (dative lif) “animated corporeal existence; lifetime, period between birth and death; the history of an individual from birth to death, written account of a person’s life; way of life (good or bad); condition of being a living thing, opposite of death; spiritual existence imparted by God, through Christ, to the believer,” from Proto-Germanic *leiban (source also of Old Norse lif “life, body,” Old Frisian, Old Saxon lif “life, person, body,” Dutch lijf “body,” Old High German lib “life,” German Leib “body”), properly “continuance, perseverance,” from PIE root *leip- “to stick, adhere.” (Source.)

“Biology,” on the other hand, appears to be an introduced word, both into German, as well as into French (a Latin language), in the late 1700s or early 1800s.

Here is the entry from etymonline.com:

biology (n.)
“the science of life and living things,” 1819, from Greek bios “life, one’s life, lifetime” (from PIE root *gwei- “to live;” see bio-) + -logy “study of.” Suggested 1802 by German naturalist Gottfried Reinhold Treviranus, and introduced as a scientific term that year in French by Lamarck; they seem to have hit upon the word independently.

They “seem to have hit upon the word independently“? Yeah, I don’t think so….

Merriam Webster, which today is owned by a Jewish financier in Switzerland, states:

First Known Use of biology

1799, in the meaning defined at sense 1

History and Etymology for biology

German Biologie, from bi- + -logie -logy

From Dictionary.com:

ORIGIN OF BIOLOGY

From the German word Biologie, dating back to 1805–15.

What they seem to agree upon is that the word we know today as “biology” was an introduced word from the early 1800s coming to use in the English from the German.

So what all was going on in Germany and Europe during this time period?

This was the period of history often referred to as the “Great Awakening” in Europe.

We have the rise of the House of Rothschild, for example, taking over the banking industry. We have the secret societies like the Freemason lodges, and the Illuminati, all taking form in Europe during this time, and influencing academics.

The theories of Marxism were written by Karl Marx and the theories of race development and the “Aryan Race” was written by Karl Ritter, and these two opposing theories would shape political and academic thought that shaped Western Culture in Europe, and was exported to the United States.

There were some positive influences also from the “Reformation Movement” during that time that at least worked at translating the Scriptures into the vernacular of the languages of the working classes.

But the biggest development from this time period, by far, which gave birth to “biology,” was Charles Darwin, and this theories of “evolution.”

Here is the entry on “biology” from encyclopedia.com:

BIOLOGY.

Biology comes from the Greek word for life, bis, and the Greek word for thought or reasoning, logos. It denotes the science that studies life, the properties and processes that sustain life, the evolutionary history of life, and particular living organisms. It is a science of enormous diversity, breadth, and heterogeneity unified only by the conceptual framework provided by the theory of evolution.

Indeed, as famously noted in 1973 by the Russian evolutionary geneticist Theodosius Dobzhansky (1900–1975), “Nothing in biology makes sense except in the light of evolution”—a quote now replicated in so many university-level textbooks that it is almost a dictum in modern biology.

During this time period the definition of “science” began to evolve from a meaning that historically was synonymous with “knowledge” and “philosophy” and began to limit its study to strictly the bios of life, concerning only the physical life between our physical birth and physical death, and all the elements of Satan’s world system such as pride, lust, greed, etc., and eliminate all other meanings of “life” as “unscientific.”

Today, in American academics, you are generally not allowed to challenge Darwin’s theories of evolution, theories which have undergone many changes over the years, as it is presented as a scientific “fact,” even though it is only a theory which is really not supported by science at all.

The actual science that Darwin (and others) observed were primarily species adapting to their environment, in order to survive, and not evolving into a higher life form which in this theory takes BILLIONS of years to happen, and could never be observed by science, but just accepted by faith.

What we have completely lost in modern day academics, is the teaching that life comes from our Creator, and our Savior, Jesus Christ. And along with this view of “life,” is a declining emphasis on the humanities and arts, the creative expression of human life, as “science” is now regulated to only physical science, based mainly on Darwinian Biology, which, among other things, has given us modern medicine and the pharmaceutical industry with its very narrow, and very evil, view of “life” that came from bios.

Transhumanism’s False Claims

I have wanted to write an article for some time now debunking all the false claims for “transhumanism.” But as I began to study the language used to define and describe “life,” I quickly realized that the easiest way to debunk transhumanism is to first properly define “life.”

Once we realize what life really is, we can easily see that the promises, or warnings, depending on who you are reading or listening to, regarding transhumanism are all based on a false definition of “life”.

Transhumanism is nothing more than the 21st Century version of Darwinian biology, based on bios, instead of zoe and psuche. Modern academic teaching has turned the meaning of life upside down, putting the lowest forms of “life” that deal only with physical life and the elements of this world system on top, and eliminating the human soul and spirit completely.

If you want to live your life like that, ignoring your soul and your spirit, go ahead. You will fit into modern society just fine, along with the modern belief in the religious cult of “medicine” and their priests called “doctors.”

This false belief that originates with the Greek concept of bios, and popularized and institutionalized with academic thought built upon “biology,” is what produced the false science known today as “genetics,” which was originally called “eugenics,” until it was associated with Nazi Germany and Hitler and perceived as negative.

Therefore it was rebranded as “genetics,” and it is what fuels most “scientific” research today that gives us modern day drugs and vaccines, which never promote a healthy life, but merely manage disease at best, or kills life prematurely at its worst. For more information on this topic, see our previous articles:

Mapping the Genome and Modern Genetics: Eugenics Repackaged for Modern Times

Eugenics in the United States Today: Are We on the Same Path Nazi Germany Followed?

Dr. David Martin Exposes the False Foundation of Eugenics: “You Don’t Have DNA”

To understand the false science of “genetics” and “biology,” you first need to understand what true “life” really is, which includes your eternal soul and your spirit.

All life originates from God, through Jesus Christ. I quoted these verses above, and the Greek word for “all” is pas, which really means ALL, or the WHOLE.

That means neither man, nor Satan, can create life. Period. End of story.

They can affect our physical bodies and the bios that we live from physical birth to physical death, but neither man nor Satan has control of our soul or spirit.

Do not be afraid of those who kill the body but cannot kill the soul. Rather, be afraid of the One who can destroy both soul and body in hell. (Matthew 10:28)

We are created in the image of God, and nothing can change that, because all life originates and is upheld by God through Jesus Christ. There are no exceptions, according to the language used in the Scriptures.

What about procreation? Cannot a man and women create children through sex?

No!

We just established the fact that all life is created by God. When a man and women join together and produce a child, they are participating in the creative process with God, but they are not creating anything. God created the sperm, and the egg.

Every single person born from their mother was created by God.

For you created my inmost being; you knit me together in my mother’s womb.

I praise you because I am fearfully and wonderfully made; your works are wonderful, I know that full well.

My frame was not hidden from you when I was made in the secret place. When I was woven together in the depths of the earth, your eyes saw my unformed body.

All the days ordained for me were written in your book before one of them came to be. (Psalms 139:13-16)

If a man and a women do not have the power to create a human being, therefore, then Satan and his demons most certainly cannot create “transhumans”!! And neither can the technocrats.

I am currently seeing two forms of transhumanism being discussed in the popular culture and also in the Alternative Media.

One is put forward by the technocrats such as those who work with the World Economic Forum and have defined what they want to do with “transhumanism.”

The second is promoted mostly by Evangelical Zionist Christians who believe that Satan can procreate and produce hybrid demons/humans, and much of this is based on the Book of Enoch, which was rejected as an authentic piece of literature to be included in the Bible.

And as I have shown here in this article, probably the main reason why the Book of Enoch was not included in the Bible is that it has a false definition of “life.” The Biblical definition of “life” sees ALL life as originating with God, and even being upheld in the universe today by God.

The writers of the New Testament dealt very strongly with the issues taught in the Book of Enoch, which deal with “bloodlines” or genealogies and hybrid demon-human beings. Here are a few of the warnings from Paul to NOT get involved with these debates and arguments:

As I urged you when I went into Macedonia, stay there in Ephesus so that you may command certain men not to teach false doctrines any longer nor to devote themselves to myths and endless genealogies. These promote controversies rather than God’s work–which is by faith. The goal of this command is love, which comes from a pure heart and a good conscience and a sincere faith. Some have wandered away from these and turned to meaningless talk. (1 Timothy 1:3-6)

Therefore, rebuke them sharply, so that they will be sound in the faith and will pay no attention to Jewish myths or to the commands of those who reject the truth. To the pure, all things are pure, but to those who are corrupted and do not believe, nothing is pure. In fact, both their minds and consciences are corrupted. (Titus 1:13-15)

But avoid foolish controversies and genealogies and arguments and quarrels about the law, because these are unprofitable and useless. (Titus 3:9)

As far as the false claims of the technocrats, no machine, robot, or artificial intelligence can ever be defined as “life.” It is also based on the false science of “genetics,” and it is all cow dung.

These are the false prophets of our day. The Christian false prophets are terrorizing people who foolishly took a COVID-19 injection by telling them that they now cannot be healed or saved, and that their DNA has been altered and they are no longer human.

They say these things because they have a false understanding of “life,” and there is no room for God in their thinking to overcome the negative effects of the pharmaceutical cult. They need to repent.

The technocrats are from my generation, and they grew up watching Star Trek and Star Wars and actually believing all that science fiction, because they too have a false concept of “life.” They are actually not even very smart people, most of them, and as soon as their technology developed to the point where almost everyone started using it, the Globalists came in and bought them all, as they sold their souls to the Wall Street Bankers and Billionaires.

But transhumanism is only science fiction, and it always will be. AI, robots, etc. are all creations of man, corrupted by Satan, and cannot create life, nor be called “life.”

It is mainly a distraction to the real dangers of technology, and things like artificial intelligence, which is massive data processing that allows new levels of tracking and surveillance that we have never seen before.

It is one thing to spy on every single person on the planet through technology, and it is another thing to be able to process all that data and use it for evil purposes, and that is the true danger of the technocrats who are now owned by the Wall Street bankers.

But here is the truth:

Jesus answered, “I am the way and the truth and the life. No one comes to the Father except through me.” (John 14:6)

End of story.

Jesus controls life, and if we know him and have his Spirit living inside of us, we have absolutely nothing to fear, because the worst thing our enemy can do to us is kill our bios, our physical life, which is going to pass away at some point anyway, as our soul lives on into eternity without the physical body.

I declare to you, brothers, that flesh and blood cannot inherit the kingdom of God, nor does the perishable inherit the imperishable.

Listen, I tell you a mystery: We will not all sleep, but we will all be changed–in a flash, in the twinkling of an eye, at the last trumpet.

For the trumpet will sound, the dead will be raised imperishable, and we will be changed. For the perishable must clothe itself with the imperishable, and the mortal with immortality.

When the perishable has been clothed with the imperishable, and the mortal with immortality, then the saying that is written will come true: “Death has been swallowed up in victory.”

“Where, O death, is your victory? Where, O death, is your sting?” The sting of death is sin, and the power of sin is the law.

But thanks be to God! He gives us the victory through our Lord Jesus Christ.

Therefore, my dear brothers, stand firm. Let nothing move you. Always give yourselves fully to the work of the Lord, because you know that your labor in the Lord is not in vain. (1 Corinthians 15:50-58)

Comment on this article at Created4Health.org

See Also:

Understand the Times We are Currently Living Through

The God of All Comfort

Year 2023: Will America Fulfill Its Destiny? Jesus Christ is the Only “Transhuman” the World Has Ever Seen or Will Ever See

An Invitation to the Technologists to Join the Winning Side

Synagogue of Satan: Why It’s Time to Leave the Corporate Christian Church

How to Determine if you are a Disciple of Jesus Christ or Not

Epigenetics Exposes Darwinian Biology as a Religion – Your DNA Does NOT Determine Your Health!

What Happens When a Holy and Righteous God Gets Angry? Lessons from History and the Prophet Jeremiah

Insider Exposes Freemasonry as the World’s Oldest Secret Religion and the Luciferian Plans for The New World Order

Identifying the Luciferian Globalists Implementing the New World Order – Who are the “Jews”?

Published on January 23, 2022

Life Temporal range: 3770–0 Ma Pha. Proterozoic Archean Had’n Archean – Present (possible Hadean origin)
Diversity of Prokaryota which includes Archaea, Cyanobacteria, Bacillus, Campylobacteria, Enterobacteria, Diplococcus, and Spirochete
Diversity of Eukaryota which includes Gray wolf, Giant sequoia, Entodinium, Amanita caesarea, Pterois antennata, Algae blooms, Chrysotoxum verralli, Xanthoparmelia lichen, Dictyostelium, and Pillar coral
Scientific classification
Domains and Supergroups
Life on Earth: Non-cellular life[note 1][note 2] Viruses[note 3][note 4] Virusoids Viroids Cellular life Domain Bacteria Domain Archaea Domain Eukaryota Archaeplastida Plantae SAR Excavata Amoebozoa Opisthokonta Holomycota Fungi Holozoa Animalia

Life is a quality that distinguishes matter that has biological processes, such as signaling and self-sustaining processes, from matter that does not, and is defined by the capacity for growth, reaction to stimuli, metabolism, energy transformation, and reproduction.^[2][3] Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. Biology is the science that studies life.

The gene is the unit of heredity, whereas the cell is the structural and functional unit of life.^[4][5] 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 and passes its genes onto a new generation, sometimes producing genetic variation.

Organisms, or the individual entities of life, are generally thought to be 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 over multiple generations. Other definitions sometimes include non-cellular life forms such as viruses and viroids, but they are usually excluded because they do not function on their own; rather, they exploit the biological processes of hosts.^[6][7]

Abiogenesis, also known as the origin of life, is the natural process of life arising from non-living matter, such as simple organic compounds. Since its primordial beginnings, life on Earth has changed its environment on a geologic time scale, but it has also adapted to survive in most ecosystems and conditions. New lifeforms have evolved from common ancestors through hereditary variation and natural selection, and today, estimates of the number of distinct species range anywhere from 3 million to over 100 million.^[3][8]

Death is the permanent termination of all biological processes which sustain an organism, and as such, is the end of its life. Extinction is the term describing the dying-out of a group or taxon, usually a species. Once extinct, the extinct species or taxon cannot come back to life. Fossils are the preserved remains or traces of organisms.

Definitions

The definition of life has long been a challenge for scientists and philosophers.^[9][10][11] This is partially because life is a process, not a substance.^[12][13][14] This is complicated by a lack of knowledge of the characteristics of living entities, if any, that may have developed outside of Earth.^[15][16] Philosophical definitions of life have also been put forward, with similar difficulties on how to distinguish living things from the non-living.^[17] Legal definitions of life have also been described and debated, though these generally focus on the decision to declare a human dead, and the legal ramifications of this decision.^[18] As many as 123 definitions of life have been compiled.^[19]

Biology

Since there is no consensus for a definition of life, most current definitions in biology are descriptive. Life is considered a characteristic of something that preserves, furthers or reinforces its existence in the given environment. This characteristic exhibits all or most of the following traits:^{[11][20][21][2][22][23][24]}

1. Homeostasis: regulation of the internal environment to maintain a constant state; for example, sweating to reduce temperature
2. Organisation: being structurally composed of one or more cells – the basic units of life
3. Metabolism: transformation of energy by converting chemicals and energy into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organisation (homeostasis) and to produce the other phenomena associated with life.
4. Growth: maintenance of a higher rate of anabolism than catabolism. A growing organism increases in size in all of its parts, rather than simply accumulating matter.
5. Adaptation: the evolutionary process whereby an organism becomes better able to live in its habitat or habitats.^[25][26][27]
6. Response to stimuli: a response can take many forms, from the contraction of a unicellular organism to external chemicals, to complex reactions involving all the senses of multicellular organisms. A response is often expressed by motion; for example, the leaves of a plant turning toward the sun (phototropism), and chemotaxis.
7. Reproduction: the ability to produce new individual organisms, either asexually from a single parent organism or sexually from two parent organisms.

These complex processes, called physiological functions, have underlying physical and chemical bases, as well as signaling and control mechanisms that are essential to maintaining life.

Alternative definitions

From a physics perspective, living beings are thermodynamic systems with an organised molecular structure that can reproduce itself and evolve as survival dictates.^[28][29] Thermodynamically, life has been described as an open system which makes use of gradients in its surroundings to create imperfect copies of itself.^[30] Another way of putting this is to define life as «a self-sustained chemical system capable of undergoing Darwinian evolution», a definition adopted by a NASA committee attempting to define life for the purposes of exobiology, based on a suggestion by Carl Sagan.^[31][32][33] This definition, however, has been widely criticized because according to it, a single sexually reproducing individual is not alive as it is incapable of evolving on its own.^[34] The reason for this potential flaw is that «NASA’s definition» refers to life as a phenomenon, not a living individual, which makes it incomplete.^[35] Alternative, definitions based on the notion of life as a phenomenon and a living individual have been proposed as continuum of a self-maintainable information, and a distinct element of this continuum, respectively. A major strength of this approach is that it defines life in terms of mathematics and physics, avoiding biological vocabulary, which inevitably leads to pleonasticity.^[35]

Others take a systemic viewpoint that does not necessarily depend on molecular chemistry. One systemic definition of life is that living things are self-organizing and autopoietic (self-producing). Variations of this definition include Stuart Kauffman’s definition as an autonomous agent or a multi-agent system capable of reproducing itself or themselves, and of completing at least one thermodynamic work cycle.^[36] This definition is extended by the apparition of novel functions over time.^[37]

Viruses

Whether or not viruses should be considered as alive is controversial. They are most often considered as just gene coding replicators rather than forms of life.^[38] They have been described as «organisms at the edge of life»^[39] because they possess genes, evolve by natural selection,^[40][41] and replicate by making multiple copies of themselves through self-assembly. However, viruses do not metabolise and they require a host cell to make new products. Virus self-assembly within host cells has implications for the study of the origin of life, as it may support the hypothesis that life could have started as self-assembling organic molecules.^[42][43][44]

Biophysics

To reflect the minimum phenomena required, other biological definitions of life have been proposed,^[45] with many of these being based upon chemical systems. Biophysicists have commented that living things function on negative entropy.^[46][47] In other words, living processes can be viewed as a delay of the spontaneous diffusion or dispersion of the internal energy of biological molecules towards more potential microstates.^[9] In more detail, according to physicists such as John Bernal, Erwin Schrödinger, Eugene Wigner, and John Avery, life is a member of the class of phenomena that are open or continuous systems able to decrease their internal entropy at the expense of substances or free energy taken in from the environment and subsequently rejected in a degraded form.^[48][49] The emergence and increasing popularity of biomimetics or biomimicry (the design and production of materials, structures, and systems that are modelled on biological entities and processes) will likely redefine the boundary between natural and artificial life.^[50]

Living systems theories

Living systems are open self-organizing living things that interact with their environment. These systems are maintained by flows of information, energy, and matter.

Budisa, Kubyshkin and Schmidt defined cellular life as an organizational unit resting on four pillars/cornerstones: (i) energy, (ii) metabolism, (iii) information and (iv) form. This system is able to regulate and control metabolism and energy supply and contains at least one subsystem that functions as an information carrier (genetic information). Cells as self-sustaining units are parts of different populations that are involved in the unidirectional and irreversible open-ended process known as evolution.^[51]

Some scientists have proposed in the last few decades that a general living systems theory is required to explain the nature of life.^[52] Such a general theory would arise out of the ecological and biological sciences and attempt to map general principles for how all living systems work. Instead of examining phenomena by attempting to break things down into components, a general living systems theory explores phenomena in terms of dynamic patterns of the relationships of organisms with their environment.^[53]

Gaia hypothesis

The idea that Earth is alive is found in philosophy and religion, but the first scientific discussion of it was by the Scottish scientist James Hutton. In 1785, he stated that Earth was a superorganism and that its proper study should be physiology. Hutton is considered the father of geology, but his idea of a living Earth was forgotten in the intense reductionism of the 19th century.^[54]: 10 The Gaia hypothesis, proposed in the 1960s by scientist James Lovelock,^[55][56] suggests that life on Earth functions as a single organism that defines and maintains environmental conditions necessary for its survival.^[54] This hypothesis served as one of the foundations of the modern Earth system science.

Self-maintainable information

All living entities posess genetic information that maintains itself by processess called cis-actions.^[35] Cis-action is any action that has an impact on the initiator, and in chemical systems is known as the autocatalytic set. In living systems, all the cis-actions have generally a positive influence on the system as those with negative impact are eliminated by natural selection. Genetic information acts as an initiator, and it can maintain itself via a series of cis-actions like self-repair or self-production (the production of parts of the body to be distinguished from self-reproduction, which is a duplication of the entire entity). Various cis-actions give the entity additional traits to be considered alive. Self-maintainable information is a basic requirement — a level zero for gaining lifeness and it can be obtained by any cis-action like self-repair (like a gene coding a protein that fixes alteration to a nucleic acid caused by UV radiation). Subsequently, if the entity is able to perform error-prone self-reproduction it gains the trait of evolution and belongs to a continuum of self-maintainable information — it becomes part of the living world in meaning of phenomenon but not yet a living individual. For this upgrade, the entity has to process the trait of distinctness, understood as an ability to define itself as a separate entity with its own fate. There are two possible ways of reaching distinctness: 1) maintaining an open-system (a cell) or/and 2) maintaining a transmission process (for obligatory parasites). Fulfiling any of these cis-actions raises the entity to a level of living individual — a distinct element of the self-maintainable information’s continuum. The final level regards the state of the entity as dead or alive and requires the trait of functionality.^[35]

This approach provides a lather-like hierarchy of entities depending on their ability to maintain themselves, their evolvability, and their distinctness. It also distinguishes between life as a phenomenon, a living individual, and an alive individual.^[35]

Nonfractionability

Robert Rosen devoted a large part of his career, from 1958^[57] onwards, to developing a comprehensive theory of life as a self-organizing complex system, «closed to efficient causation».^{[note 5]} He defined a system component as «a unit of organization; a part with a function, i.e., a definite relation between part and whole.» He identified the «nonfractionability of components in an organism» as the fundamental difference between living systems and «biological machines.» He summarised his views in his book Life Itself.^[58] Similar ideas may be found in the book Living Systems^[59] by James Grier Miller.

Property of ecosystems

A systems view of life treats environmental fluxes and biological fluxes together as a «reciprocity of influence,»^[60] and a reciprocal relation with environment is arguably as important for understanding life as it is for understanding ecosystems. As Harold J. Morowitz (1992) explains it, life is a property of an ecological system rather than a single organism or species.^[61] He argues that an ecosystemic definition of life is preferable to a strictly biochemical or physical one. Robert Ulanowicz (2009) highlights mutualism as the key to understand the systemic, order-generating behaviour of life and ecosystems.^[62]

Complex systems biology

Complex systems biology (CSB) is a field of science that studies the emergence of complexity in functional organisms from the viewpoint of dynamic systems theory.^[63] The latter is also often called systems biology and aims to understand the most fundamental aspects of life. A closely related approach to CSB and systems biology called relational biology is concerned mainly with understanding life processes in terms of the most important relations, and categories of such relations among the essential functional components of organisms; for multicellular organisms, this has been defined as «categorical biology», or a model representation of organisms as a category theory of biological relations, as well as an algebraic topology of the functional organisation of living organisms in terms of their dynamic, complex networks of metabolic, genetic, and epigenetic processes and signalling pathways.^[64][65] Alternative but closely related approaches focus on the interdependence of constraints, where constraints can be either molecular, such as enzymes, or macroscopic, such as the geometry of a bone or of the vascular system.^[66]

Darwinian dynamic

It has also been argued that the evolution of order in living systems and certain physical systems obeys a common fundamental principle termed the Darwinian dynamic.^[67][68] The Darwinian dynamic was formulated by first considering how macroscopic order is generated in a simple non-biological system far from thermodynamic equilibrium, and then extending consideration to short, replicating RNA molecules. The underlying order-generating process was concluded to be basically similar for both types of systems.^[67]

Operator theory

Another systemic definition called the operator theory proposes that life is a general term for the presence of the typical closures found in organisms; the typical closures are a membrane and an autocatalytic set in the cell^[69] and that an organism is any system with an organisation that complies with an operator type that is at least as complex as the cell.^{[70][71][72][73]} Life can also be modelled as a network of inferior negative feedbacks of regulatory mechanisms subordinated to a superior positive feedback formed by the potential of expansion and reproduction.^[74]

History of study

Materialism

Some of the earliest theories of life were materialist, holding that all that exists is matter, and that life is merely a complex form or arrangement of matter. Empedocles (430 BC) argued that everything in the universe is made up of a combination of four eternal «elements» or «roots of all»: earth, water, air, and fire. All change is explained by the arrangement and rearrangement of these four elements. The various forms of life are caused by an appropriate mixture of elements.^[75]

Democritus (460 BC) thought that the essential characteristic of life is having a soul (psyche). Like other ancient writers, he was attempting to explain what makes something a living thing. His explanation was that fiery atoms make a soul in exactly the same way atoms and void account for any other thing. He elaborates on fire because of the apparent connection between life and heat, and because fire moves.^[76]

Plato’s world of eternal and unchanging Forms, imperfectly represented in matter by a divine Artisan, contrasts sharply with the various mechanistic Weltanschauungen, of which atomism was, by the fourth century at least, the most prominent … This debate persisted throughout the ancient world. Atomistic mechanism got a shot in the arm from Epicurus … while the Stoics adopted a divine teleology … The choice seems simple: either show how a structured, regular world could arise out of undirected processes, or inject intelligence into the system.^[77]

— R.J. Hankinson, Cause and Explanation in Ancient Greek Thought

The mechanistic materialism that originated in ancient Greece was revived and revised by the French philosopher René Descartes (1596–1650), who held that animals and humans were assemblages of parts that together functioned as a machine. This idea was developed further by Julien Offray de La Mettrie (1709–1750) in his book L’Homme Machine.^[78]

In the 19th century the advances in cell theory in biological science encouraged this view. The evolutionary theory of Charles Darwin (1859) is a mechanistic explanation for the origin of species by means of natural selection.^[79]

At the beginning of the 20th century Stéphane Leduc (1853–1939) promoted the idea that biological processes could be understood in terms of physics and chemistry, and that their growth resembled that of inorganic crystals immersed in solutions of sodium silicate. His ideas, set out in his book La biologie synthétique^[80] was widely dismissed during his lifetime, but has incurred a resurgence of interest in the work of Russell, Barge and colleagues.^[81]

Hylomorphism

Hylomorphism is a theory first expressed by the Greek philosopher Aristotle (322 BC). The application of hylomorphism to biology was important to Aristotle, and biology is extensively covered in his extant writings. In this view, everything in the material universe has both matter and form, and the form of a living thing is its soul (Greek psyche, Latin anima). There are three kinds of souls: the vegetative soul of plants, which causes them to grow and decay and nourish themselves, but does not cause motion and sensation; the animal soul, which causes animals to move and feel; and the rational soul, which is the source of consciousness and reasoning, which (Aristotle believed) is found only in man.^[82] Each higher soul has all of the attributes of the lower ones. Aristotle believed that while matter can exist without form, form cannot exist without matter, and that therefore the soul cannot exist without the body.^[83]

This account is consistent with teleological explanations of life, which account for phenomena in terms of purpose or goal-directedness. Thus, the whiteness of the polar bear’s coat is explained by its purpose of camouflage. The direction of causality (from the future to the past) is in contradiction with the scientific evidence for natural selection, which explains the consequence in terms of a prior cause. Biological features are explained not by looking at future optimal results, but by looking at the past evolutionary history of a species, which led to the natural selection of the features in question.^[84]

Spontaneous generation

Spontaneous generation was the belief that living organisms can form without descent from similar organisms. Typically, the idea was that certain forms such as fleas could arise from inanimate matter such as dust or the supposed seasonal generation of mice and insects from mud or garbage.^[85]

The theory of spontaneous generation was proposed by Aristotle,^[86] who compiled and expanded the work of prior natural philosophers and the various ancient explanations of the appearance of organisms; it was considered the best explanation for two millennia. It was decisively dispelled by the experiments of Louis Pasteur in 1859, who expanded upon the investigations of predecessors such as Francesco Redi.^[87][88] Disproof of the traditional ideas of spontaneous generation is no longer controversial among biologists.^[89][90][91]

Vitalism

Vitalism is the belief that the life-principle is non-material. This originated with Georg Ernst Stahl (17th century), and remained popular until the middle of the 19th century. It appealed to philosophers such as Henri Bergson, Friedrich Nietzsche, and Wilhelm Dilthey,^[92] anatomists like Xavier Bichat, and chemists like Justus von Liebig.^[93] Vitalism included the idea that there was a fundamental difference between organic and inorganic material, and the belief that organic material can only be derived from living things. This was disproved in 1828, when Friedrich Wöhler prepared urea from inorganic materials.^[94] This Wöhler synthesis is considered the starting point of modern organic chemistry. It is of historical significance because for the first time an organic compound was produced in inorganic reactions.^[93]

During the 1850s Hermann von Helmholtz, anticipated by Julius Robert von Mayer, demonstrated that no energy is lost in muscle movement, suggesting that there were no «vital forces» necessary to move a muscle.^[95] These results led to the abandonment of scientific interest in vitalistic theories, especially after Buchner’s demonstration that alcoholic fermentation could occur in cell-free extracts of yeast.^[96]
Nonetheless, the belief still exists in pseudoscientific theories such as homoeopathy, which interprets diseases and sickness as caused by disturbances in a hypothetical vital force or life force.^[97]

Origin

The age of Earth is about 4.54 billion years.^{[98][99][100]} Evidence suggests that life on Earth has existed for at least 3.5 billion years,^{[101][102][103][104][105][106][107][108][109]} with the oldest physical traces of life dating back 3.7 billion years;^{[110][111][112]} however, some hypotheses, such as Late Heavy Bombardment, suggest that life on Earth may have started even earlier, as early as 4.1–4.4 billion years ago,^{[101][102][103][104][105]} and the chemistry leading to life may have begun shortly after the Big Bang, 13.8 billion years ago, during an epoch when the universe was only 10–17 million years old.^{[113][114][115]} Time estimates from molecular clocks, as summarized in TimeTree, generally place the origin of life around 4.0 billion years ago or earlier.^[116]

More than 99% of all species of life forms, amounting to over five billion species,^[117] that ever lived on Earth are estimated to be extinct.^[118][119]

Although the number of Earth’s catalogued species of lifeforms is between 1.2 million and 2 million,^[121][122] the total number of species in the planet is uncertain. Estimates range from 8 million to 100 million,^[121][122] with a more narrow range between 10 and 14 million,^[121] but it may be as high as 1 trillion (with only one-thousandth of one per cent of the species described) according to studies realised in May 2016.^[123][124] The total number of related DNA base pairs on Earth is estimated at 5.0 x 10³⁷ and weighs 50 billion tonnes.^[125] In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC (trillion tons of carbon).^[126] In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor (LUCA) of all organisms living on Earth.^[127]

All known life forms share fundamental molecular mechanisms, reflecting their common descent; based on these observations, hypotheses on the origin of life attempt to find a mechanism explaining the formation of a universal common ancestor, from simple organic molecules via pre-cellular life to protocells and metabolism. Models have been divided into «genes-first» and «metabolism-first» categories, but a recent trend is the emergence of hybrid models that combine both categories.^[128]

There is no current scientific consensus as to how life originated. However, most accepted scientific models build on the Miller–Urey experiment and the work of Sidney Fox, which show that conditions on the primitive Earth favoured chemical reactions that synthesize amino acids and other organic compounds from inorganic precursors,^[129] and phospholipids spontaneously form lipid bilayers, the basic structure of a cell membrane.

Living organisms synthesize proteins, which are polymers of amino acids using instructions encoded by deoxyribonucleic acid (DNA). Protein synthesis entails intermediary ribonucleic acid (RNA) polymers. One possibility for how life began is that genes originated first, followed by proteins;^[130] the alternative being that proteins came first and then genes.^[131]

However, because genes and proteins are both required to produce the other, the problem of considering which came first is like that of the chicken or the egg. Most scientists have adopted the hypothesis that because of this, it is unlikely that genes and proteins arose independently.^[132]

Therefore, a possibility, first suggested by Francis Crick,^[133] is that the first life was based on RNA,^[132] which has the DNA-like properties of information storage and the catalytic properties of some proteins. This is called the RNA world hypothesis, and it is supported by the observation that many of the most critical components of cells (those that evolve the slowest) are composed mostly or entirely of RNA. Also, many critical cofactors (ATP, Acetyl-CoA, NADH, etc.) are either nucleotides or substances clearly related to them. The catalytic properties of RNA had not yet been demonstrated when the hypothesis was first proposed,^[134] but they were confirmed by Thomas Cech in 1986.^[135]

One issue with the RNA world hypothesis is that synthesis of RNA from simple inorganic precursors is more difficult than for other organic molecules. One reason for this is that RNA precursors are very stable and react with each other very slowly under ambient conditions, and it has also been proposed that living organisms consisted of other molecules before RNA.^[136] However, the successful synthesis of certain RNA molecules under the conditions that existed prior to life on Earth has been achieved by adding alternative precursors in a specified order with the precursor phosphate present throughout the reaction.^[137] This study makes the RNA world hypothesis more plausible.^[138]

Geological findings in 2013 showed that reactive phosphorus species (like phosphite) were in abundance in the ocean before 3.5 Ga, and that Schreibersite easily reacts with aqueous glycerol to generate phosphite and glycerol 3-phosphate.^[139] It is hypothesized that Schreibersite-containing meteorites from the Late Heavy Bombardment could have provided early reduced phosphorus, which could react with prebiotic organic molecules to form phosphorylated biomolecules, like RNA.^[139]

In 2009, experiments demonstrated Darwinian evolution of a two-component system of RNA enzymes (ribozymes) in vitro.^[140] The work was performed in the laboratory of Gerald Joyce, who stated «This is the first example, outside of biology, of evolutionary adaptation in a molecular genetic system.»^[141]

Prebiotic compounds may have originated extraterrestrially. NASA findings in 2011, based on studies with meteorites found on Earth, suggest DNA and RNA components (adenine, guanine and related organic molecules) may be formed in outer space.^{[142][143][144][145]}

In March 2015, NASA scientists reported that, for the first time, complex DNA and RNA organic compounds of life, including uracil, cytosine and thymine, have been formed in the laboratory under outer space conditions, using starting chemicals, such as pyrimidine, found in meteorites. Pyrimidine, like polycyclic aromatic hydrocarbons (PAHs), the most carbon-rich chemical found in the universe, may have been formed in red giants or in interstellar dust and gas clouds, according to the scientists.^[146]

According to the panspermia hypothesis, microscopic life—distributed by meteoroids, asteroids and other small Solar System bodies—may exist throughout the universe.^[147][148]

Environmental conditions

The diversity of life on Earth is a result of the dynamic interplay between genetic opportunity, metabolic capability, environmental challenges,^[149] and symbiosis.^{[150][151][152]} For most of its existence, Earth’s habitable environment has been dominated by microorganisms and subjected to their metabolism and evolution. As a consequence of these microbial activities, the physical-chemical environment on Earth has been changing on a geologic time scale, thereby affecting the path of evolution of subsequent life.^[149] For example, the release of molecular oxygen by cyanobacteria as a by-product of photosynthesis induced global changes in the Earth’s environment. Because oxygen was toxic to most life on Earth at the time, this posed novel evolutionary challenges, and ultimately resulted in the formation of Earth’s major animal and plant species. This interplay between organisms and their environment is an inherent feature of living systems.^[149]

Biosphere

The biosphere is the global sum of all ecosystems. It can also be termed as the zone of life on Earth, a closed system (apart from solar and cosmic radiation and heat from the interior of the Earth), and largely self-regulating.^[153] By the most general biophysiological definition, the biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, geosphere, hydrosphere, and atmosphere.

Life forms live in every part of the Earth’s biosphere, including soil, hot springs, inside rocks at least 19 km (12 mi) deep underground, the deepest parts of the ocean, and at least 64 km (40 mi) high in the atmosphere.^{[154][155][156]} Under certain test conditions, life forms have been observed to thrive in the near-weightlessness of space^[157][158] and to survive in the vacuum of outer space.^[159][160] Life forms appear to thrive in the Mariana Trench, the deepest spot in the Earth’s oceans.^[161][162] Other researchers reported related studies that life forms thrive inside rocks up to 580 m (1,900 ft; 0.36 mi) below the sea floor under 2,590 m (8,500 ft; 1.61 mi) of ocean off the coast of the northwestern United States,^[161][163] as well as 2,400 m (7,900 ft; 1.5 mi) beneath the seabed off Japan.^[164] In August 2014, scientists confirmed the existence of life forms living 800 m (2,600 ft; 0.50 mi) below the ice of Antarctica.^[165][166] According to one researcher, «You can find microbes everywhere—they’re extremely adaptable to conditions, and survive wherever they are.»^[161]

The biosphere is postulated to have evolved, beginning with a process of biopoesis (life created naturally from non-living matter, such as simple organic compounds) or biogenesis (life created from living matter), at least some 3.5 billion years ago.^[167][168] The earliest evidence for life on Earth includes biogenic graphite found in 3.7 billion-year-old metasedimentary rocks from Western Greenland^[110] and microbial mat fossils found in 3.48 billion-year-old sandstone from Western Australia.^[111][112] More recently, in 2015, «remains of biotic life» were found in 4.1 billion-year-old rocks in Western Australia.^[102][103] In 2017, putative fossilised microorganisms (or microfossils) were announced to have been discovered in hydrothermal vent precipitates in the Nuvvuagittuq Belt of Quebec, Canada that were as old as 4.28 billion years, the oldest record of life on Earth, suggesting «an almost instantaneous emergence of life» after ocean formation 4.4 billion years ago, and not long after the formation of the Earth 4.54 billion years ago.^{[169][170][171][172]} According to biologist Stephen Blair Hedges, «If life arose relatively quickly on Earth … then it could be common in the universe.»^[102]

In a general sense, biospheres are any closed, self-regulating systems containing ecosystems. This includes artificial biospheres such as Biosphere 2 and BIOS-3, and potentially ones on other planets or moons.^[173]

Range of tolerance

The inert components of an ecosystem are the physical and chemical factors necessary for life—energy (sunlight or chemical energy), water, heat, atmosphere, gravity, nutrients, and ultraviolet solar radiation protection.^[174] In most ecosystems, the conditions vary during the day and from one season to the next. To live in most ecosystems, then, organisms must be able to survive a range of conditions, called the «range of tolerance.»^[175] Outside that are the «zones of physiological stress,» where the survival and reproduction are possible but not optimal. Beyond these zones are the «zones of intolerance,» where survival and reproduction of that organism is unlikely or impossible. Organisms that have a wide range of tolerance are more widely distributed than organisms with a narrow range of tolerance.^[175]

Extremophiles

To survive, selected microorganisms can assume forms that enable them to withstand freezing, complete desiccation, starvation, high levels of radiation exposure, and other physical or chemical challenges. These microorganisms may survive exposure to such conditions for weeks, months, years, or even centuries.^[149] Extremophiles are microbial life forms that thrive outside the ranges where life is commonly found.^[176] They excel at exploiting uncommon sources of energy. While all organisms are composed of nearly identical molecules, evolution has enabled such microbes to cope with this wide range of physical and chemical conditions. Characterization of the structure and metabolic diversity of microbial communities in such extreme environments is ongoing.^[177]

Microbial life forms thrive even in the Mariana Trench, the deepest spot in the Earth’s oceans.^[161][162] Microbes also thrive inside rocks up to 1,900 feet (580 m) below the sea floor under 8,500 feet (2,600 m) of ocean.^[161][163] Expeditions of the International Ocean Discovery Program found unicellular life in 120 °C sediment that is 1.2 km below seafloor in the Nankai Trough subduction zone.^[178]

Investigation of the tenacity and versatility of life on Earth,^[176] as well as an understanding of the molecular systems that some organisms utilise to survive such extremes, is important for the search for life beyond Earth.^[149] For example, lichen could survive for a month in a simulated Martian environment.^[179][180]

Chemical elements

All life forms require certain core chemical elements needed for biochemical functioning. These include carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur—the elemental macronutrients for all organisms^[181]—often represented by the acronym CHNOPS. Together these make up nucleic acids, proteins and lipids, the bulk of living matter. Five of these six elements comprise the chemical components of DNA, the exception being sulfur. The latter is a component of the amino acids cysteine and methionine. The most biologically abundant of these elements is carbon, which has the desirable attribute of forming multiple, stable covalent bonds. This allows carbon-based (organic) molecules to form an immense variety of chemical arrangements.^{[citation needed]} Alternative hypothetical types of biochemistry have been proposed that eliminate one or more of these elements, swap out an element for one not on the list, or change required chiralities or other chemical properties.^[182][183]

DNA

Main article: DNA

Deoxyribonucleic acid is a molecule that carries most of the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms and many viruses. DNA and RNA are nucleic acids; alongside proteins and complex carbohydrates, they are one of the three major types of macromolecule that are essential for all known forms of life. Most DNA molecules consist of two biopolymer strands coiled around each other to form a double helix. The two DNA strands are known as polynucleotides since they are composed of simpler units called nucleotides.^[184] Each nucleotide is composed of a nitrogen-containing nucleobase—either cytosine (C), guanine (G), adenine (A), or thymine (T)—as well as a sugar called deoxyribose and a phosphate group. The nucleotides are joined to one another in a chain by covalent bonds between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone. According to base pairing rules (A with T, and C with G), hydrogen bonds bind the nitrogenous bases of the two separate polynucleotide strands to make double-stranded DNA. The total amount of related DNA base pairs on Earth is estimated at 5.0 x 10³⁷, and weighs 50 billion tonnes.^[125] In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC (trillion tons of carbon).^[126]

DNA stores biological information. The DNA backbone is resistant to cleavage, and both strands of the double-stranded structure store the same biological information. Biological information is replicated as the two strands are separated. A significant portion of DNA (more than 98% for humans) is non-coding, meaning that these sections do not serve as patterns for protein sequences.

The two strands of DNA run in opposite directions to each other and are, therefore, anti-parallel. Attached to each sugar is one of four types of nucleobases (informally, bases). It is the sequence of these four nucleobases along the backbone that encodes biological information. Under the genetic code, RNA strands are translated to specify the sequence of amino acids within proteins. These RNA strands are initially created using DNA strands as a template in a process called transcription.

Within cells, DNA is organised into long structures called chromosomes. During cell division these chromosomes are duplicated in the process of DNA replication, providing each cell its own complete set of chromosomes. Eukaryotic organisms (animals, plants, fungi, and protists) store most of their DNA inside the cell nucleus and some of their DNA in organelles, such as mitochondria or chloroplasts.^[185] In contrast, prokaryotes (bacteria and archaea) store their DNA only in the cytoplasm. Within the chromosomes, chromatin proteins such as histones compact and organise DNA. These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed.

DNA was first isolated by Friedrich Miescher in 1869.^[186] Its molecular structure was identified by James Watson and Francis Crick in 1953, whose model-building efforts were guided by X-ray diffraction data acquired by Rosalind Franklin.^[187]

Classification

Antiquity

The first known attempt to classify organisms was conducted by the Greek philosopher Aristotle (384–322 BC), who classified all living organisms known at that time as either a plant or an animal, based mainly on their ability to move. He also distinguished animals with blood from animals without blood (or at least without red blood), which can be compared with the concepts of vertebrates and invertebrates respectively, and divided the blooded animals into five groups: viviparous quadrupeds (mammals), oviparous quadrupeds (reptiles and amphibians), birds, fishes and whales. The bloodless animals were also divided into five groups: cephalopods, crustaceans, insects (which included the spiders, scorpions, and centipedes, in addition to what we define as insects today), shelled animals (such as most molluscs and echinoderms), and «zoophytes» (animals that resemble plants). Though Aristotle’s work in zoology was not without errors, it was the grandest biological synthesis of the time and remained the ultimate authority for many centuries after his death.^[188]

Linnaean

The exploration of the Americas revealed large numbers of new plants and animals that needed descriptions and classification. In the latter part of the 16th century and the beginning of the 17th, careful study of animals commenced and was gradually extended until it formed a sufficient body of knowledge to serve as an anatomical basis for classification.

In the late 1740s, Carl Linnaeus introduced his system of binomial nomenclature for the classification of species. Linnaeus attempted to improve the composition and reduce the length of the previously used many-worded names by abolishing unnecessary rhetoric, introducing new descriptive terms and precisely defining their meaning.^[189] The Linnaean classification has eight levels: domains, kingdoms, phyla, class, order, family, genus, and species.

The fungi were originally treated as plants. For a short period Linnaeus had classified them in the taxon Vermes in Animalia, but later placed them back in Plantae. Copeland classified the Fungi in his Protoctista, thus partially avoiding the problem but acknowledging their special status.^[190] The problem was eventually solved by Whittaker, when he gave them their own kingdom in his five-kingdom system. Evolutionary history shows that the fungi are more closely related to animals than to plants.^[191]

As new discoveries enabled detailed study of cells and microorganisms, new groups of life were revealed, and the fields of cell biology and microbiology were created. These new organisms were originally described separately in protozoa as animals and protophyta/thallophyta as plants, but were united by Haeckel in the kingdom Protista; later, the prokaryotes were split off in the kingdom Monera, which would eventually be divided into two separate groups, the Bacteria and the Archaea. This led to the six-kingdom system and eventually to the current three-domain system, which is based on evolutionary relationships.^[192] However, the classification of eukaryotes, especially of protists, is still controversial.^[193]

As microbiology, molecular biology and virology developed, non-cellular reproducing agents were discovered, such as viruses and viroids. Whether these are considered alive has been a matter of debate; viruses lack characteristics of life such as cell membranes, metabolism and the ability to grow or respond to their environments. Viruses can still be classed into «species» based on their biology and genetics, but many aspects of such a classification remain controversial.^[194]

In May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one per cent described.^[123]

The original Linnaean system has been modified over time as follows:

Linnaeus 1735[195]	Haeckel 1866[196]	Chatton 1925[197]	Copeland 1938[198]	Whittaker 1969[199]	Woese et al. 1990[192]	Cavalier-Smith 1998[200]	Cavalier-Smith 2015[201]
2 kingdoms	3 kingdoms	2 empires	4 kingdoms	5 kingdoms	3 domains	2 empires, 6 kingdoms	2 empires, 7 kingdoms
(not treated)	Protista	Prokaryota	Monera	Monera	Bacteria	Bacteria	Bacteria
Archaea	Archaea
Eukaryota	Protoctista	Protista	Eucarya	Protozoa	Protozoa
Chromista	Chromista
Vegetabilia	Plantae	Plantae	Plantae	Plantae	Plantae
Fungi	Fungi	Fungi
Animalia	Animalia	Animalia	Animalia	Animalia	Animalia

Cells

Cells are the basic unit of structure in every living thing, and all cells arise from pre-existing cells by division. Cell theory was formulated by Henri Dutrochet, Theodor Schwann, Rudolf Virchow and others during the early nineteenth century, and subsequently became widely accepted.^[202] The activity of an organism depends on the total activity of its cells, with energy flow occurring within and between them. Cells contain hereditary information that is carried forward as a genetic code during cell division.^[203]

There are two primary types of cells. Prokaryotes lack a nucleus and other membrane-bound organelles, although they have circular DNA and ribosomes. Bacteria and Archaea are two domains of prokaryotes. The other primary type of cells are the eukaryotes, which have distinct nuclei bound by a nuclear membrane and membrane-bound organelles, including mitochondria, chloroplasts, lysosomes, rough and smooth endoplasmic reticulum, and vacuoles. In addition, they possess organised chromosomes that store genetic material. All species of large complex organisms are eukaryotes, including animals, plants and fungi, though most species of eukaryote are protist microorganisms.^[204] The conventional model is that eukaryotes evolved from prokaryotes, with the main organelles of the eukaryotes forming through endosymbiosis between bacteria and the progenitor eukaryotic cell.^[205]

The molecular mechanisms of cell biology are based on proteins. Most of these are synthesised by the ribosomes through an enzyme-catalyzed process called protein biosynthesis. A sequence of amino acids is assembled and joined based upon gene expression of the cell’s nucleic acid.^[206] In eukaryotic cells, these proteins may then be transported and processed through the Golgi apparatus in preparation for dispatch to their destination.^[207]

Cells reproduce through a process of cell division in which the parent cell divides into two or more daughter cells. For prokaryotes, cell division occurs through a process of fission in which the DNA is replicated, then the two copies are attached to parts of the cell membrane. In eukaryotes, a more complex process of mitosis is followed. However, the result is the same; the resulting cell copies are identical to each other and to the original cell (except for mutations), and both are capable of further division following an interphase period.^[208]

Multicellular organisms may have first evolved through the formation of colonies of identical cells. These cells can form group organisms through cell adhesion. The individual members of a colony are capable of surviving on their own, whereas the members of a true multi-cellular organism have developed specialisations, making them dependent on the remainder of the organism for survival. Such organisms are formed clonally or from a single germ cell that is capable of forming the various specialised cells that form the adult organism. This specialisation allows multicellular organisms to exploit resources more efficiently than single cells.^[209] In January 2016, scientists reported that, about 800 million years ago, a minor genetic change in a single molecule, called GK-PID, may have allowed organisms to go from a single cell organism to one of many cells.^[210]

Cells have evolved methods to perceive and respond to their microenvironment, thereby enhancing their adaptability. Cell signalling coordinates cellular activities, and hence governs the basic functions of multicellular organisms. Signaling between cells can occur through direct cell contact using juxtacrine signalling, or indirectly through the exchange of agents as in the endocrine system. In more complex organisms, coordination of activities can occur through a dedicated nervous system.^[211]

Though life is confirmed only on Earth, many think that extraterrestrial life is not only plausible, but probable or inevitable.^[212][213] Other planets and moons in the Solar System and other planetary systems are being examined for evidence of having once supported simple life, and projects such as SETI are trying to detect radio transmissions from possible alien civilisations. Other locations within the Solar System that may host microbial life include the subsurface of Mars, the upper atmosphere of Venus,^[214] and subsurface oceans on some of the moons of the giant planets.^[215][216]
Beyond the Solar System, the region around another main-sequence star that could support Earth-like life on an Earth-like planet is known as the habitable zone. The inner and outer radii of this zone vary with the luminosity of the star, as does the time interval during which the zone survives. Stars more massive than the Sun have a larger habitable zone, but remain on the Sun-like «main sequence» of stellar evolution for a shorter time interval. Small red dwarfs have the opposite problem, with a smaller habitable zone that is subject to higher levels of magnetic activity and the effects of tidal locking from close orbits. Hence, stars in the intermediate mass range such as the Sun may have a greater likelihood for Earth-like life to develop.^[217] The location of the star within a galaxy may also affect the likelihood of life forming. Stars in regions with a greater abundance of heavier elements that can form planets, in combination with a low rate of potentially habitat-damaging supernova events, are predicted to have a higher probability of hosting planets with complex life.^[218] The variables of the Drake equation are used to discuss the conditions in planetary systems where civilisation is most likely to exist.^[219] Use of the equation to predict the amount of extraterrestrial life, however, is difficult; because many of the variables are unknown, the equation functions as more of a mirror to what its user already thinks. As a result, the number of civilisations in the galaxy can be estimated as low as 9.1 x 10⁻¹³, suggesting a minimum value of 1, or as high as 15.6 million (1.56 x 10⁸); for the calculations, see Drake equation.

A «Confidence of Life Detection» scale (CoLD) for reporting evidence of life beyond Earth has been proposed.^[220][221]

Artificial

Artificial life is the simulation of any aspect of life, as through computers, robotics, or biochemistry.^[222] The study of artificial life imitates traditional biology by recreating some aspects of biological phenomena. Scientists study the logic of living systems by creating artificial environments—seeking to understand the complex information processing that defines such systems. While life is, by definition, alive, artificial life is generally referred to as data confined to a digital environment and existence.

Synthetic biology is a new area of biotechnology that combines science and biological engineering. The common goal is the design and construction of new biological functions and systems not found in nature. Synthetic biology includes the broad redefinition and expansion of biotechnology, with the ultimate goals of being able to design and build engineered biological systems that process information, manipulate chemicals, fabricate materials and structures, produce energy, provide food, and maintain and enhance human health and the environment.^[223]

Death

Death is the termination of all vital functions or life processes in an organism or cell.^[224][225] It can occur as a result of an accident, violence, medical conditions, biological interaction, malnutrition, poisoning, senescence, or suicide. After death, the remains of an organism re-enter the biogeochemical cycle. Organisms may be consumed by a predator or a scavenger and leftover organic material may then be further decomposed by detritivores, organisms that recycle detritus, returning it to the environment for reuse in the food chain.

One of the challenges in defining death is in distinguishing it from life. Death would seem to refer to either the moment life ends, or when the state that follows life begins.^[225] However, determining when death has occurred is difficult, as cessation of life functions is often not simultaneous across organ systems.^[226] Such determination, therefore, requires drawing conceptual lines between life and death. This is problematic, however, because there is little consensus over how to define life. The nature of death has for millennia been a central concern of the world’s religious traditions and of philosophical inquiry. Many religions maintain faith in either a kind of afterlife or reincarnation for the soul, or resurrection of the body at a later date.^[227]

Extinction

Extinction is the process by which a group of taxa or species dies out, reducing biodiversity.^[228] The moment of extinction is generally considered the death of the last individual of that species. Because a species’ potential range may be very large, determining this moment is difficult, and is usually done retrospectively after a period of apparent absence. Species become extinct when they are no longer able to survive in changing habitat or against superior competition. Over 99% of all the species that have ever lived are now extinct.^{[229][117][118][119]} Mass extinctions may have accelerated evolution by providing opportunities for new groups of organisms to diversify.^[230]

Fossils

Fossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossil-containing rock formations and sedimentary layers (strata) is known as the fossil record. A preserved specimen is called a fossil if it is older than the arbitrary date of 10,000 years ago.^[231] Hence, fossils range in age from the youngest at the start of the Holocene Epoch to the oldest from the Archaean Eon, up to 3.4 billion years old.^[232][233]

See also

Notes

References

Further reading

• Walker, Martin G. (2006). LIFE! Why We Exist … And What We Must Do to Survive. Dog Ear Publishing. ISBN 978-1-59858-243-7. Archived from the original on 24 July 2011.

External links

• Life (Systema Naturae 2000)
• Vitae (BioLib)
• Biota (Taxonomicon)
• Wikispecies – a free directory of life
• Resources for life in the Solar System and in galaxy, and the potential scope of life in the cosmological future
• «The Adjacent Possible: A Talk with Stuart Kauffman»
• Stanford Encyclopedia of Philosophy entry
• The Kingdoms of Life

Presentation on theme: «The Meaning of the “Life”»— Presentation transcript:

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The Meaning of the “Life”
Jordyn Hancock Date: Mod:7/8

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What is your meaning of the word “Life?”
___________________________________________________________

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Dictionary Definition
“The meaning of life is a philosophical question concerning the purpose and significance of human existence”

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Why I did a Project on the “Meaning of Life.”
I wanted to see what other people of other ages thought of the meaning of life. I know that the meaning of life is infinite according to all people’s life styles.

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Thesis Statement No matter the age or the time period you lived in there is no definite meaning of life it all depends on your lifestyle and surroundings.

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Socrates In Socrates schools “instead of lecturing Socrates listened to what other people were saying. Then he asked them questions to make them think more deeply about their own ideas. This way of thinking is called the ‘Socratic Method” “Beware the bareness (emptiness) of a busy life.”

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Plato Plato was a student of Socrates that really admired him.
Plato left Athens for 12 years after Socrates died and when he came back 12 years later he followed after Socrates steps and made his own school of philosophy. “NO one can be good or have knowledge without asking questions.”

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Ralph Waldo Emerson “Life is a progress, and not a station.”

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Sydney J. Harris “Strictly Personal”
“When I heard somebody sigh, ‘Life is hard,’ I am always tempted to ask, ‘Compared to what?”

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Barack Obama “Everyday I wake up trying to figure out how I can secure…the futures of all children…giving a planet and a country to them that is better than the one we got…”

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Here’s what my family thinks…

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Autumn Latara Hancock Age: 5
Question: 1. What do you like doing that is fun for you? 2. What makes life sad or hard for you?” Answers: 1. “Going to school and riding the bus.” 2. “Getting in trouble.”

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Kayla Ann Evans Age: 9 Questions: Answers:
1.What do you like doing that is fun for you? 2.What makes you sad or mad? Answers: 1.“Playing soccer and playing with my friends.” 2.“When I do chores.”

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Jasmine Nicole Hinds Age: 13
Questions: 1. What makes life fun for you? 2. What makes life hard or stressful for you? Answers: 1.“Making new friends and hanging with friends.” 2. “Drama, haters, and people who judge a book by it’s cover!”

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Brianna Talia Griffin Age: 16
Questions: 1.What makes life fun for you? 2.What makes life hard or stressful for you? Answers: 1.“Eating, hanging out with friends, and getting money.” 2.“PEOPLE!!!”

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Farah Maria Evans Age: 30 Questions: Answers:
1.What makes life meaningful to you? 2.What’s your meaning of life to you? Answers: 1.“Family and helping others.” 2.“Being happy, giving back, and spending time with your family.”

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Cecile Annette Hinds Age: 66
Questions: 1.What makes life meaningful to you? 2.What’s your meaning of life to you? Answers: 1.“Living for the Lord Jesus and trusting Him to take care of me.” 2.“The meaning of life is living a life that pleases God-loving our neighbors.”

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Conclusion In conclusion all of the above personal quotes from real life people show that there is not just one definite meaning of life it all depends on the way you live your life.