What is Organism: Definition and 46 Discussions

In biology, an organism (from Greek: ὀργανισμός, organismos) is any organic living system that functions as an individual entity. All organisms are composed of cells. Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fungi; or unicellular microorganisms such as protists, bacteria, and archaea. All types of organisms are capable of reproduction, growth and development, maintenance, and some degree of response to stimuli. Humans, squids, mushrooms, and vascular plants are examples of multicellular organisms that differentiate specialized tissues and organs during development.
A unicellular organism may be either a prokaryote or a eukaryote. Prokaryotes are represented by two separate domains – bacteria and archaea. Eukaryotic organisms are characterized by the presence of a membrane-bound cell nucleus and contain additional membrane-bound compartments called organelles (such as mitochondria in animals and plants and plastids in plants and algae, all generally considered to be derived from endosymbiotic bacteria). Fungi, animals and plants are examples of kingdoms of organisms within the eukaryotes.
Estimates on the number of Earth's current species range from 2 million to 1 trillion, of which over 1.7 million have been documented. More than 99% of all species, amounting to over five billion species, that ever lived are estimated to be extinct.In 2016, a set of 355 genes from the last universal common ancestor (LUCA) of all organisms was identified.

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  1. C

    B Tardigrade is first multicellular organism to be quantum entangled

    https://www.newscientist.com/article/2302337-tardigrade-is-first-multicellular-organism-to-be-quantum-entangled/ A tardigrade has been quantum entangled with a superconducting qubit – and lived to tell the tale. It is the first time a multicellular organism has been placed in this strange...
  2. S

    What Is the Simplest Organism Capable of Emotion?

    <moderator moved to General Discussion> What is the simplest organism with emotion? Can it occur without any nervous system?
  3. D

    What was the first living organism?

    What was the first life form and how would you make the distinction or cutoff from what is inanimate and what is living? When do mixes of molecules stop being particles and start being alive?
  4. I

    Organism tissue splitting off and rejoining

    Hello, I am having a hard time finding what the terminology and examples are for multicellular organisms that can have tissues rip/split off and then rejoin later, not even necessarily in the same part of the organism. I heard that perhaps jellyfish can do this. I am pretty sure I saw that...
  5. Suyash Singh

    What Are Some Examples of Gaseous Living Organisms?

    I cannot find on google. Can you give me examples of living beings that are in the from of gas like water vapour or smoke or anything else that is a gas. Like jellyfish is made of water Humans are solid
  6. Ygggdrasil

    Semi-synthetic organism with an expanded genetic code

    All life on Earth stores its genetic information in DNA using just four nucleotide letters: A, T, C, and G. Research published this week in the journal Nature describes how scientists engineered a bacterium to incorporate two new letters into their DNA (which they call X and Y, pictured below)...
  7. I

    Do cells in the body stay in one place once they have found their position?

    Once cells in the body "find their place" between other neighboring cells, do they stay there touching each other in the same way or do they move around, migrating, sliding around with their membranes? Can a cell just "take off"? I wonder the same about neuron cells and their axons and...
  8. F

    Interpreting gram stain results...unknown organism

    Homework Statement We've been given unknowns and now have to determine what the organism is. I'm having trouble interpreting gram staining results. As far morphology they are all cocci and (sort of) in clusters but (this is the confusing part) they are both purple and pink. I understand that...
  9. I

    Are there genes that are expressed in every cell in organism

    I know that different cells in a body express different genes and thus have different functionalities. I am wondering if there are genes that are expressed in all the cells of a certain organism. (or for that matter in all the cells that have that specific gene, for example all mammals.)? For...
  10. I

    Is there a common name for protective layer of an organism?

    Hello, is there a common name/word/terminology for any protective layers on an organism, for example, skin on humans, bark on a tree, etc?
  11. Keiran OConnor

    Micro organism brought back to life after 30 years

    http://gizmodo.com/frozen-tardigrade-brought-back-to-life-after-30-years-1753152359 Sorry if this is the wrong place for this post am only posting to get a few good responses if possible :). Is there any way we could extract the properties in the gnome of the tardigrade and genetically...
  12. akeleti8

    B Potential Organism Sustaining Planets

    Hi there. So it seems there are multiple reasons for why our galaxy will come to an end. A potential cause is that a black hole will engulf our sun. Let's say that in another galaxy a star is born. There is a chance that a nearby planet will have the potential for sustaining organisms. How...
  13. Stephanus

    Percentage of hydrocarbons in living organism

    Dear PF Forum, I'm interested in how much energy our organic waste contain. I have read this article https://en.wikipedia.org/wiki/Composition_of_the_human_body Elements composition of plants The elements composition of human body (and animal?) and plants resemble. Bacteria has slightly...
  14. praveena

    Existence of living organism on Mars?

    "Apparently, they have spotted a ‘woman like’ creature on Mars with the help of their Curiosity Rover".My question is: At low temperature & cosmic radiation, along with low gravity can we find a living organism? Is the above quoted lines was true? i have noted this news recently on facebook...
  15. G

    Computer simulation of an organism

    Is it possible,at least theoretically, to take digitised DNA and produce a computer simulation of the organism that it came from?
  16. Ygggdrasil

    A, T, C, G, X and Y: An New Organism with Unnatural DNA

    Published today in Nature, researchers report engineering an organism capable of replicating DNA with an unnatural base pair (X-Y) in addition to the two normal base pairs found in DNA (A-T and C-G). Here's what the unnatural base pair looks like (in comparison to the C-G base pair)...
  17. W

    Ways an organism can survive in extreme conditions.

    Lets ay there is a 0.5 Earth mass and 0.8 Earth radii planet orbiting a Sun like star at the same distance Earth is orbiting its Sun. Its atmospheric pressure would be 0.03 bar. Water boils at 75 degrees F at this pressure. How could an organism living on the surface survive? Another...
  18. aleemudasir

    Death of an Organism: Event or Series of Events?

    Is death an event or a series of events?
  19. B

    Which has least entropy- living organism or same mass as chrystal?

    Which has the least entropy? A 1kg diamond vs 1kg living organism I've gather that living things are generally at a state of low entropy compared to the same matter in other configurations- as though complexity goes hand in hand with low entropy. Yet a perfect chrystal is supposedly low...
  20. H

    How does an organism know the sequence of a protein?

    When a foreign protein is introduced in a rabbit or a mouse, its immune system attacks the protein by antibodies which specifically recognize the protein. How does the body know the sequence of the protein such that it manufactes an antibody which will specifically target that non-self protein.
  21. S

    Genetic Modification of a Live Organism Is it Possible?

    *** I know this is of questionable ethics, but I am asking a hypothetical *** If we had a human of adult age, let's say, age 20-30. Would it be possible to genetically modify all cells in the body and make the changes take effect in a realistic manner? If so what would be the limits and steps...
  22. H

    Living Organism versus Electricity

    I was wondering for quite a while what would happen if you exposed a living organism to electricity of ~250.000 Ampère at 1.000.000 Volts (I'm unsure if the values given are insanely high or not). Would the organism just end up "everywhere" or something else??
  23. Pythagorean

    What are xenophyophores and how do they form their unique structures?

    I never knew... http://en.wikipedia.org/wiki/Xenophyophore Fascinating!
  24. E

    Can You Squish a Unicellular Organism? 🤔

    I have a very pressing ::wink:: question. Is it possible to squish a unicellular organism?
  25. Krunchyman

    How should a non-cellular metal organism maintain homeostasis?

    So, I'm drafting out a science fiction being. It's a bipedal, anaerobic, autotrophic sentient being that is almost entirely mechanical and it has no DNA or cellular structure - instead, it's physiology is a maze of gears and metal mechanisms (although they do store information somewhat...
  26. T

    Does this biomimesis use the organism as an actual model or just inspiration?

    This article* describes the innovation in aerodynamics of placing the tail at the front of the aircraft to resemble the crest of a pterosaur decreased such planes' turning radii. But I'm guessing there are some big divergences in the physics of the planes' and the pterosaurs' similar parts...
  27. B

    Adam and Eve versus our ancestral marine organism

    Folks, Can anyone recommend any books regarding the argument of we unlikely came from 'adam and eve' (devine intervention) versus evolutionary evidence etc etc Thanks bugatti
  28. nukeman

    Do we know what type of organism first started life on Earth?

    I am not sure on this, so hope someone can shed some light on this. What type of organism was thought to be among the first on earth? I am not sure if this is the right way to ask this :) Lets say if I wanted to see, or do tests on an organism, and my tests were related to doing tests on...
  29. R

    After the death of an organism

    What happens to the energy that binds the molecules together? Where does it go; what does it become?
  30. H

    Curious about organism without a pulsating heart.

    I'm here doing some god awful physiology lab report about to write a paragraph on mean arterial blood pressure and was thinking about the pumping mechanism and was tying to think if there was any such organism which has a continuous flow fluid transport system, and if so what's the biggest one...
  31. F

    Min # of cells in a multicellular organism

    Given a multicellular organism, what is the theoretic minimum amount of cells it can have? Theory aside, what is the smallest known mulitcellular organism? Furthermore, anyone know of any links that show a table of organism and # of cells? Much thanks!
  32. D

    Water percentage of an organism

    I am curious, how do scientists come up with facts like a human is xx% water? I saw on a documentary recently that a jelly fish is 96% water. How is this measured and determined? What about other elements and materials?
  33. W

    How does gravity affect organism size on different planets?

    According to the DK documentary Eyewitness -- Life (VHS), Galileo correctly calculated that the tallest Earthling lifeforms can get is ~300'. The tallest Sequoia's are almost exactly that tall. I'm told this has to do with the limits of Capillary Action, which allows organisms to pump water...
  34. C

    Unicellular Organism Survival on Single Substance

    can an extremely simple unicellular organism survive off of one type of substance such as an extremely simple fat, and just break it down to use its energy. What would be the simplest type of fat or form of energy? Also if a simple unicellular organism doesn't want to do anything can it just...
  35. B

    Who can tell the name of such organism.

    who can tell the name of such organism. I want to buy it from agency, but I don't know how to call it! It is very urgent, pls tell me, thx!
  36. Ahmed Abdullah

    Does an unicellular organism die out of starvation?

    Does an unicellular organism die... if it does not get nutrient substancees for a long time? What I mean by death is that it does not replicate it's dna, trancribe gene and translate them to protein, carry out metabolic processes as it normally does, even when there are surplus nutrient...
  37. E

    What would happen if you create an organism with all junk DNA spliced out?

    What would happen if you create an organism with all junk DNA spliced out? While some introns are needed, it appears most DNA does not serve any function. Could a viable yeast or mouse be created with all junk DNA taken out?
  38. J

    Am I a Single Organism or a Network of Millions?

    1 organism, or millions?? I was just thinking, considering I am made up of millions (billions?) of cells, am I a single organism, or a network, kind of like I suppose a collaboration of millions? Is each one of my cells an organism in its own right? Are my sperm each their own organism, or...
  39. A

    Naturally occurring acid base buffering system in an organism

    I tried looking for this online, but didn't really find anything can someone help me out I need an example of a naturally- occurring acid-base buffering system in an organism
  40. F

    Explaining the origin of first living organism?

    I ask for a brief answer; can you build a building without ground floor? you cannot. how can you build a theory without explaining the origin of first living organism? Give me a logical answer
  41. T

    Genes of a single-celled organism and the genes of a multi-cellular

    What is the difference between the genes of a single-celled organism and the genes of a multi-cellular organism? I mean could the genes of a single celled organism be used in a certain way in a multi-cellular organism? Thanks
  42. J

    Nanobes too small to be living organism

    i did a search, but found no threads on this topic. i am sure all of you are aware of nanobes, but i have some confusion. when i first read about nanobes, they were a minor mystery, and while there was some debate over their nature, it was generally agreed upon that they were too small to be...
  43. Monique

    Why C. elegans is a good model organism

    besides the fact it is a eukaryote, what makes this little nematode worm a good model for human disease? Also besides the fact the lineage of every single cell of the organism has been determined? How does its immune system work, what organs does it have?
  44. wasteofo2

    Name of microscopic organism that photosynthesises and has phlagellum.

    I remember looking at this animal under a microscope in 7th grade, but I just cannot remember it's name. It had a phlagellum, moved around freely, would actively pursue food, was roughly the shape of a protist, and was green due to its chloroplast. So if anyone could tell me it's kingdom/phylum...
  45. Another God

    Safety in Genetically Modified Organism - tRNA

    This idea just struck me. I think it might be one of those ideas which could be revolutionary, but at the same time, it could also just as equally be a stupid idea which everyone who knows what they are talking about can instantly see as a waste of time and money and completely...
  46. Monique

    Development of multicellular organism

    I have always wondered how an multicellular organism develops into such a complex, but highly reproducible being.. now, I’ve been reading ‘Development of Multicellular Organisms’from the book: Molecular Biology of the Cell by Alberts et al. and it all seems so simple! (the basic ideas at least...