Naked Science Forum
Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: MarianaM on 14/10/2019 11:34:10
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Dhruv asks...
What is life in biological terms? What parameters are considered to declare a thing as living?
What's the answer?
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Living things transpire, either oxidising carbon compounds to produce energy, or using some other form of energy (solar, volcanic, etc) to produce complex carbon compounds from inorganic molecules.
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What is life in biological terms?
Asking in this way already assumes that life must be biological, hence any answer given will not be useful when deciding if some newly discovered thing (on a new planet say) is life or not.
So the answer to the question above is: It is life if you and it share a common ancestor.
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So the answer to the question above is: It is life if you and it share a common ancestor.
What about fully synthetic bacteria?
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deciding if some newly discovered thing (on a new planet say) is life or not.So the answer to the question above is: It is life if you and it share a common ancestor.
That's a very prejudiced religious statement! Since life evolved from non-life on this planet, it could equally have evolved elsewhere in the universe with no common ancestry. And whilst some people might claim to trace my ancestry back to Adam, any anti-Semite would be horrified at the thought of common ancestry
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Can assemble(grow) matter. Most Replicate. Then dissolve.
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Mules don't replicate, but they are alive.
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So the answer to the question above is: It is life if you and it share a common ancestor.
What about fully synthetic bacteria?
If it's bacteria, then its genetics has been copied (and perhaps modified) from some sample, making it related to that sample.
Thinking about this brings up an interesting point about being related to something. Bacteria doesn't really have ancestors, and hence I'm technically not related to it by the exact wording I used.
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Asking what causes life is like asking what caused the cosmos. We can not discover or determine these things.
We can only study and describe the activity of the present. What life is doing now. Life is completely different from nature. Life has a transmittable code(information), thru off spring.
The only thing that has permanence, is the code, which gets changed/adjusted along the way.
And the physical result is, a self adjusting biosphere of duration.
This extra life force/property is only detected on earth. And it is an extremely stubborn force.
The nature of the cosmos can make atoms, elements and certain molecules. And all this nature follows a set of rules, which can not be changed by nature. It's limited.
But this life force can build very complicated molecular structures, and give the structures function and animation. Structures building structures. Something happens here that is very unique, growth. And as a double whammy.......reproduction. And a final bummer......an unavoidable tragedy, death. We are a stepping stone.
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Life has a transmittable code(information), thru off spring
I have huge, sterile trees in my garden - no transmissible code, but you can grow another tree from a cutting, and they are definitely alive. I have live human friends whose genetic code is not transmissible. Monsanto have spent a fortune patenting sterile wheat. Most bees are sterile. Reproduction is not a necessary characteristic of life.
Nobody has ever detected a "life force". Its existence is only demonstrated by its absence! There are plenty of candidate planets in the universe where terrestrial chemistry is possible, but we haven't explored them yet.
We don't know that the "rules" can't be changed. All the evidence suggests that they changed significantly about 13.5 billion years ago in this corner of the universe, and they are in any case descriptive, not prescriptive.
Death is not a tragedy. It is essential for the life of animals that plants die, and vice versa, and if we did not die the world would be full of old people with no room for our offspring. Some deaths are inconvenient but the graveyards are full of people who considered themselves indispensable.
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All context has a bell curve.
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Mules don't replicate, but they are alive.
Right. But the cells making up the mules do replicate.
I think it is possible to use technology to make mules reproduce, perhaps by modifying some of the genes that prevent proper conception and gestation.
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If you modified the genes of a mule, it wouldn't be a mule.
A mule is the offspring of a male donkey and a female horse. Horses and donkeys are different species, with different numbers of chromosomes.
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If you modified the genes of a mule, it wouldn't be a mule. A mule is the offspring of a male donkey and a female horse. Horses and donkeys are different species, with different numbers of chromosomes.
Not necesarily. A few percentage of non-african modern humans' genes came from Neanderthals and Denisovans. We still call them humans. Humans with a few novel mutations are still considered human. I don't know how much genetic change is the threshold to stop calling them humans. Ditto for the mules.
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There is no consistent definition of "species" - it's a label of convenience for whatever is different from anything else. But a mule (equus mule) is an animal bred from a female horse and a male donkey and they are all sterile but alive. By all means muck about with the genes and make something that looks like a mule but is fertile (you will probably need to make two!)
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Mules don't replicate, but they are alive.
A horse has 64 chromosomes and a donkey has 62. A mule inherits 63.An even number of chromosomes is needed to divide into pairs and reproduce.
In other words,
- Mitosis (normal cell division) can work with 63 chromosomes: Each mule's "daughter" cell ends up with 63 chromosomes, and survives.
- But Meiosis (production of egg and sperm) takes matched pairs of chromosomes, and puts one of each pair in the egg or sperm cell.
- In a mule, there is one chromosome with no partner.
- So the egg or sperm can end up with a random mixture of horse and donkey genes, with or without the extra horse chromosome.
- The odds are greatly against it, but it is possible that the egg or sperm could end up with 100% horse or 100% donkey DNA, which would be fertile.
For an exception, see: https://www.denverpost.com/2007/07/25/mules-foal-fools-genetics-with-impossible-birth/
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Asking what causes life is like asking what caused the cosmos. We can not discover or determine these things.
Why do you consider that statement to be valid?
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Valid, because it contains a subject, verb and object that plausibly relate to each other. Whether it is provable is an entirely different matter!
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It's been a valid statement so far. Does anyone know how the cosmos started? Do you believe that we can "discover" how it was started? How are you going to do that?
Do we even understand, what we are looking at?
Same with life. No one has ever seen it start. It is passed, not started.
Will we ever understand the passed on life, in order to be able to start it.
Could it be possible......that new life can not be started at the present time?
Is it possible for a new cosmos to form now?
Is life in it's own separate "time zone"? Like light.
Let's first try to answer the questions that we CAN answer............it MIGHT change the way we ask the BIG questions. And look for those answers.
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Obviously we can't literally discover something that has already happened, but we can put together a plausible hypothesis of how. This leads me to wonder why anyone would bother. Apart from idle curiosity, that is. Do you want to build another cosmos?
As far as we know, life is a very improbable, complicated and temporary phenomenon, but there is no reason to think it hasn't happened elsewhere or won't occur somewhere else in the universe at some time, or that biogenesis is dependent on a law of physics that has been repealed. We have found (indeed we are) one needle in a haystack, but that finding doesn't preclude the possibility of others or imply a magical haystack.
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It's been a valid statement so far. Does anyone know how the cosmos started? Do you believe that we can "discover" how it was started? How are you going to do that?
Life is part of the present. Only when it is considered that life started at some point in time, causality could be an argument to state that the origin of life cannot be determined. However, as it appears, there is no basis for such an assumption. Therefore, there is either a pending requirement to determine the origin of life or to explain why it cannot be determined.
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Being, that we don't know everything......we have to assume. The question is, when we do assume, should we assume a positive, because we can't find a negative..........or should we assume negative, because we can't find a positive?
I prefer to assume negative......because it limits the possibilities.
I believe that there is only one true solution......or understanding. The solution can appear different from different viewpoints, but there is only one dynamic that can express those viewpoints.
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It would be like gambling with a similar chance of being correct as with tossing a coin.
If an answer is not known, it may be best to acknowledge it and try to find new methods for discovering an answer.
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Dhruv asks...
What is life in biological terms? What parameters are considered to declare a thing as living?
What's the answer?
Life is none biological , biological material is just a conduit for the real you which is an energy entity .
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Life is a fuzzy concept. https://en.wikipedia.org/wiki/Fuzzy_concept
A lot of things can be classified as living or not living, but the boundary itself can appear blurry.
Life is a characteristic that distinguishes physical entities that have biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased (they have died), or because they never had such functions and are classified as inanimate. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. The criteria can at times be ambiguous and may or may not define viruses, viroids, or potential synthetic life as "living". Biology is the science concerned with the study of life.
There is currently no consensus regarding the definition of life. One popular definition is that organisms are open systems that maintain homeostasis, are composed of cells, have a life cycle, undergo metabolism, can grow, adapt to their environment, respond to stimuli, reproduce and evolve. However, several other definitions have been proposed, and there are some borderline cases of life, such as viruses or viroids.
https://en.wikipedia.org/wiki/Life
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To make productive discussion possible, we need to have useful definition of life. That definition must be broad enough to include (almost) all systems that commonly regarded as life, but at the same time specific enough to exclude (almost) all systems that commonly regarded as non-life. In other word, it must be balanced to minimize false negative as well as false positive cases.
I think the popular definition in Wikipedia above is too narrow, hence has high probability to get false negative case, such as the mule that was dicussed above. I prefer a broader definition than this, like "having the ability to duplicate genetic material with minimum support". I leave the definition of "minimum support" here to discuss.
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Dhruv asks...
What is life in biological terms? What parameters are considered to declare a thing as living?
What's the answer?
Do not waste your life trying to measure it.
Enjoy your life and learn to treasure it.
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Do not waste your life trying to measure it.
Enjoy your life and learn to treasure it.
On what basis would the indicated value of life be defined? It occurs that your statement could be seen as an argument for choosing religion over science.
Enjoying life and learning to treasure it can be seen as a plausible advice for a valuable result in life (on an individual level) but the question remains why one should simply accept the origin of life as inexplicable.
When the origin of life is accepted as inexplicable, one could just as well consider life meaningless or an effect of pure randomness. With such a perception, the multi-trillion USD synthetic biology revolution in which humans attempt to top-down control the fabric of nature, would be justifiable. From the resulting mental perception there would be no logical argument against it. Life would not be considered a factor that requires consideration (other than that on individual or corporate level).
In my opinion it may be best to not factor out the origin of life.
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This finding may blur distinction between life and non-life even further.
In most biology textbooks, there’s a clear separation between the three domains of cellular organisms – Bacteria, Archaea, and Eukaryotes – and viruses. This fault line is also typically accepted as the divider between life and non-life: since viruses rely on host machinery to enact metabolic transformations and to replicate, they are not self-sufficient, and generally not considered living entities.
But several discoveries of giant viruses over the last decade have blurred this distinction. Some viruses are even larger and contain more genes than typical microbes like E. coli. Ultra-small bacteria detected in filtered groundwater from Rifle, Colorado are moving the goalposts from the opposite end, leading to a virus-microbe continuum in which distinguishing one from the other isn’t so straightforward. Among the alluring interpretations: giant viruses could be indicative of a fourth domain of life.
A recent study led by Frederik Schulz at the Department of Energy’s Joint Genome Institute blurs the virus-microbe line even further. While assembling a metagenome from sewage sludge in Klosterneuburg, Austria, Schulz found several genes that all mapped back to the same unknown virus, genes that until now have only been associated with free-living cells.
The particle – named Klosneuvirus – is still a virus, given its other genes and outer coat, but its 1.57 million-base genome allows a greater degree of autonomy than many of its viral relatives. Most notably, they have a relatively complete complement of protein-making machinery, which would reduce the dependence on host cells to do their bidding. For example, most viruses lack aminoacyl tRNA synthetase enzymes, which shuttle amino acids onto transfer RNA molecules; these in turn make their way to the ribosome, dropping off their cargo to build proteins from the chains of amino acids. While some previously discovered giant viruses have seven of the 20 aminoacyl tRNA synthetases, Klosneuvirus has 19, making it almost entirely independent of host involvement in protein synthesis. (It’s also worth noting that autonomy is not a requirement for cellular life, either: many microbes are “auxotrophic,” meaning they depend on external input of organics – often amino acids – in order to survive.)
So could this sophisticated, rule-breaking giant virus indeed be a sign of the mythical fourth domain? To find out, the team compared Klosneuvirus’s aminoacyl tRNA synthetase sequences with other forms of the enzymes across the tree of life. The results were all over the place, with each synthetase showing closest similarity to a different organism (mostly algae). In the ever hyperbolic language of scientific journalese, Schulz notes that “these findings are incompatible with the fourth domain hypothesis…and instead imply piecemeal acquisition of these genes by giant viruses.” The synthetases don’t seem to have evolved together, from the same branch point and within the same organism; rather, they were scooped up by an opportunisitc virus and incorporated into an increasingly mature metabolic network.
As suggested by previous revelations of giant viruses, Klosneuvirus is likely just the beginning of a more thorough reconfiguration of the tree of life. After the intriguing result from the sewage treatment plant in Austria, Schulz looked for genomes of similar viruses, lurking in previously obtained metagenomes from around the world. He found three more – enough to propose a new subfamily, the Klosneuvirinae – the latest links in the chain connecting viruses and the three domains of cellular life.
https://www.discovermagazine.com/environment/giant-virus-found-in-sewage-blurs-the-line-between-life-and-non-life?utm_source=dsctwitter&utm_medium=social&utm_campaign=dsctwitter
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The question wants a response that would provide concepts or guidelines regarding measuring biological life. However, the question is not only a scientific one, and to answer it scientifically one must first aspire to understand the philosophical and political implementations of the answer to this question.
Strictly speaking, there is no definite boundary between biology and geology. Biology is geology. The concept "biological life" is a creation that makes it easier to classify and analyze the world around us. But, as there is no boundary, where should it be put? That is the real meaning of the above question. Therefore, my answer is that the answer to that question is a philosophical or political answer, and not a scientific one.
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Biological life is a special state of matter that distinguishes biological organisms from inorganic objects, i.e., inanimate, dead organisms, achieved through the following processes:
Speaking of life, they usually mean the life of protein bodies. Some organisms, such as bacteriophages that do not produce their proteins, do not fall into this category of lifehttp://bakerim.com/
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Biological life is a special state of matter that distinguishes biological organisms from inorganic objects, i.e., inanimate, dead organisms, achieved through the following processes:
Speaking of life, they usually mean the life of protein bodies. Some organisms, such as bacteriophages that do not produce their proteins, do not fall into this category of life. 8)
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Therefore, my answer is that the answer to that question is a philosophical or political answer, and not a scientific one.
Why do you believe that a definition of life can be a political answer? Would it be similar to stating that, instead of a scientific answer, it is a religious answer?
Speaking of life, they usually mean the life of protein bodies. Some organisms, such as bacteriophages that do not produce their proteins, do not fall into this category of life. 8)
Recent discoveries question whether bacteriophages or viruses should be excluded.
Evolutionary biologists have never known what to make of viruses, arguing over their origins for decades. But a newly discovered group of giant viruses, called Klosneuviruses, could be a 'missing link' that helps to settle the debate — or provoke even more discord.
https://www.nature.com/news/giant-virus-discovery-sparks-debate-over-tree-of-life-1.21798
Also, dead organic matter (pig brains) have been brought back to life in a laboratory.
https://www.nationalgeographic.com/science/2019/04/pig-brains-partially-revived-what-it-means-for-medicine-death-ethics/
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Living things modify their environment for their own or their successors' benefit.
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Living things modify their environment for their own or their successors' benefit.
What is the origin of the evaluation 'benefit'? Why is benefit evaluated?
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It is the judgement of the living thing itself. In most cases, the benefit is also obvious to an observer, but not necessarily so. The fundamental processes of nutrition and elimination alter the environment, extracting stuff that is necessary for the continuation of life processes and dumping stuff that would inhibit them.
The clever bit is the mutual evolution of plants that oxygenate the air and animals that carbonate it, to produce a dynamic equilibrium.
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It is the judgement of the living thing itself.
Your argument is basically "It is alive thus it is life". It doesn't explain why life exists, or why its origin cannot be explained scientifically.
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its origin cannot be explained scientifically.
How do you know that?
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It is the judgement of the living thing itself.
Your argument is basically "It is alive thus it is life". It doesn't explain why life exists, or why its origin cannot be explained scientifically.
1. Wrong.
2. That wasn't the question
3. Wrong, like "heavier than air machines can't fly". There was a time when I could not speak English, but it would have been wrong to assume I couldn't learn.
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its origin cannot be explained scientifically.
How do you know that?
I do not. It is a suggestion for a consideration. If the origin of life is inexplicable, then it must be possible to explain why. There is a requirement to provide an answer.
I find this topic very interesting, considering the time (2020).
I noticed that in science, when an answer cannot be provided, a sort of black box effect may occur. The scientific process moves around it and could be making (or indirectly/culturally cause) mistakes.
As an example, for a long time animal minds have been ignored by science. Animal minds have been considered a "black box" and wasn't given attention and thus people in general didn't know anything about it and cannot understand a problem with treating animals in a specific way (i.e. without respect).
animal minds and consciousness have been consigned to a “black box”, an entity too complex or confusing to delve into, but whose inputs and outputs become the object of study.
https://cosmosmagazine.com/society/animals-science-behaviour-and-ethics
Recent scientific developments show that even plants can be considered "slow animals" that can interact with animals (including humans) in a meaningful way.
BBC: Plants can see, hear and smell – and respond
Plants, according to Jack C Schultz, "are just very slow animals".
This is not a misunderstanding of basic biology. Schultz is a professor in the Division of Plant Sciences at the University of Missouri in Columbia, and has spent four decades investigating the interactions between plants and insects. He knows his stuff.
http://www.bbc.com/earth/story/20170109-plants-can-see-hear-and-smell-and-respond
With the question 'what is life?' something similar may be at play. Big Pharma like companies are already investing trillions of USD per year in synthetic biology to redesign life, apparently with the primary purpose to serve a short term financial interest.
Therefor my argument is that it is important to not factor out the origin of life. An answer to the question "what is life?" is important before you profoundly start to redesign it.
Humans have always modified the environment for their advantage, which is considered by some to be parasitic behaviour. However, that is different from an attempt to top down control the fabric of nature, i.e. to use science or a human (corporate) perspective as a guiding principle for nature.
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There is a requirement to provide an answer.
No, there isn't. It is perfectly acceptable to say "I don't know" and there is never any guarantee that we ever will know.
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It doesn't explain why life exists,
You can't presume a "why". "Why" is a consequence of something bigger (an intention) or more fundamental (a mechanism) than the phenomenon you are looking at, and in the case of life, we have no evidence of intention and no reason to think that it requires more than the known mechanisms of chemistry.
or why its origin cannot be explained scientifically.
Citation or proof. please.
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No, there isn't. It is perfectly acceptable to say "I don't know" and there is never any guarantee that we ever will know.
Can you explain why it is acceptable to consider that an answer to the simple question "what is life?" may not be possible? What could validate such an idea?
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You can't presume a "why". "Why" is a consequence of something bigger (an intention) or more fundamental (a mechanism) than the phenomenon you are looking at, and in the case of life, we have no evidence of intention and no reason to think that it requires more than the known mechanisms of chemistry.
Why life exists is essentially asking "what is the origin of life?". It has nothing to do with intention per se.
To answer the question "what is life?" it may be relevant to know/question how it came into existence / what could explain it (why it exists).
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Why? That is philosophical. How? That is scientific. How does life come about? That is about the mechanics. Why does life come about? That is just the burden of having an advanced intelligence and an overactive imagination.
The how of something is not always positive though. How can we make people's lives better? That is positive. How can we rig the political and economic systems to concentrate all its resources with 1% of the population? That is not so positive.
Maybe we should stop asking stupid questions, wake up and smell the BS.
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Can you explain why it is acceptable to consider that an answer to the simple question "what is life?" may not be possible?
Because we still live in a free society where you can consider anything you fancy, however ridiculous or pointless it may appear to anyone else. Words have the meaning we assign to them, and useful words have meaning by consensus. So the question "what is life" is about establishing the consensus value of the word, in the given context - in this case a scientific discussion in a biology forum.
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Why life exists is essentially asking "what is the origin of life?". It has nothing to do with intention per se.
To answer the question "what is life?" it may be relevant to know/question how it came into existence / what could explain it (why it exists).
The answer to "why" is "because....." or "in order to...."
The answer to "what" is "that which...…"
The answer to "how" is "since A causes B...."
Colloquially, we sometimes use "why" to mean "how", but you have to be more pedantic in a science forum, lest the argument be hijacked by philosophy.
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Answer to a how question can also be a step by step procedure or action, like in how something is made.
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Surely all known life forms must have biochemical reactions to form a living organism. Once there are no biochemical reactions the life form is dead
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Can you explain why it is acceptable to consider that an answer to the simple question "what is life?" may not be possible? What could validate such an idea?
The question I was talking about was the one regarding the origin of life, not what the definition of life is.
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Can you explain why it is acceptable to consider that an answer to the simple question "what is life?" may not be possible?
We have trouble identifying the borderline of life-as-we-know-it: carbon-based proteins in a water solution
- Miniature bacteria and giant viruses seem to blur the borders
However, it is quite possible that life may exist in the universe (or in the solar system) which do not conform to this familiar carbon+water paradigm.
- For example, on Titan, water is frozen rock solid, while organic solvents exist as liquids, so an entirely different form of life may (hypothetically) exist there
- Detecting this life would require careful observation and consideration of general criteria to identify life
- I expect that the confirmation of life elsewhere in the universe will require shifting the borderline multiple times
- On Titan, even human proximity as observers at a temperature of 300K would vaporize any life that is present there
It doesn't explain why life exists, or why its origin cannot be explained scientifically.
The answer to "why" is "because....." or "in order to...."
In a religious context "God made it" is an answer to "Why does life/the universe exist?"; a Prime Cause
- To which a scientist would reply with a science question: "How was life/the universe formed?", the "who" question being excluded by Occam's Razor and the French Revolution (among others)
For scientists, a possible Prime Cause for life is "Entropy"
- Living things accelerate the universal increase in entropy in order to produce a temporary, local reduction in entropy, which we call "life"
- The universal increase in entropy being an observed, statistical trend in our universe
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I beg to pick nits! No need for Occam's Razor or Madame Guillotine, just basic Anglo-Saxon:
"Joe Bloggs made it" is the answer to "who?" but "Joe Bloggs* made it in order to beat his wife with it" is the answer to "why?"
And there's the problem. God may well have done it, but why? Even the facetious answer "for his own amusement" is untenable because an omnipotent, omniscient being can't be surprised and therefore can't be amused.
*This is a work of fiction. Any resemblance to real persons living or dead is coincidental. Other wife beaters are available
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As an example, for a long time animal minds have been ignored by science. Animal minds have been considered a "black box" and wasn't given attention and thus people in general didn't know anything about it and cannot understand a problem with treating animals in a specific way (i.e. without respect).
Science is a process, not an organism, and thus can't be accused of "ignoring" anything. Some humans treat animals (including other humans) with a notable lack of respect. Nothing to do with science, largely caused by religion, politics, philosophy, and other perversions.