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What would a virus do if it caused total extinction?

  1. Aug 22, 2015 #1
    Ok so I am thinking that it is not in the best interest of a virus to cause total extinction because after that you do not have anything else to infect and sustain your virus cycle.

    So isn't a virus's best interest to just infest a host and make it want to reproduce like crazy so it could have more hosts to infect?

    What would it do if there is nothing left to infect? Wouldn't it just die and defeat all it's purpose of living inside a host and reproducing to infect others?
     
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  3. Aug 22, 2015 #2

    phinds

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    I'm not sure they think it through. :smile:
     
  4. Aug 22, 2015 #3

    Bystander

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    Given that there is a virus that is so species-specific, and that that virus is so efficient that it infects all populations of that species, it has just won a Darwin award for itself as well as its host-species. Over-specialization is its own maladaptive trait.
     
  5. Aug 23, 2015 #4
    Sometimes a virus jumps to a new host. Say ebola to humans. The virus has evolved proteins that hijack the cell's infrastructure, say a fruit bat cell.

    When these same proteins attempt to hijack a human cell, things may not go as smoothly. The cell needs to be hijacked, but the host shouldn't die.

    The most successful viruses are those that are non-pathogenic. Ebola is already becoming less virulent because the more virulent strains are dying out with their hosts; ebola is evolving as a human virus by becoming less deadly.

    So genetic entities with genes that make them go extinct, those generally do not exist for very long. Life has a bias for the exact opposite type of genes.

    As for developing a weapon that would kill every individual of a species, that is hard to do. If you don't kill the host fast enough, they have time to fight off the disease with adaptive immunity. If you kill the host too quickly, the host dies before it infects enough people and the virus dies out.
     
  6. Aug 23, 2015 #5
    The influenza virus seems to have found a comfortable niche for itself.
    It is highly contagious but usually not fatal to the host, it readily produces minor mutations which don't do much to the virus, but confuse the host's immune system, and is fairly adept in producing mutations that can infect multiple host species.
     
  7. Aug 23, 2015 #6

    FactChecker

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    Most viruses have a range of host species that it can infect. Some host species are just carriers who suffer no ill effects. One reason so few human viruses can be completely eradicated is that they can live on in other animals. So far, only smallpox has been eradicated.
     
  8. Aug 23, 2015 #7

    Student100

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    Viruses over time move to establish symbiotic relationships with their host. This occurs naturally. There is no virus we've ever encountered that has 100% infection and mortality rate. Such a scenario is probably impossible due to genetic differences within the host.
     
  9. Aug 24, 2015 #8

    SteamKing

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    Recent events would suggest that this process has not proceeded as far along as one would hope.

    Ebola is just one variety of a whole spectrum of viral hemorrhagic diseases, which are unknown by most Westerners, and some of which are so deadly, it is difficult to study them in a lab without taking extreme precautions.

    https://en.wikipedia.org/wiki/Viral_hemorrhagic_fever

    I wouldn't consider diseases like influenza to be entirely benign, either. The influenza pandemic of 1918-20 came out of nowhere, killed 50-100 million people (between 3 and 5 percent of the world population at the time), and then vanished again, almost as suddenly as it appeared. Who's to say that another great flu pandemic won't come in the future?

    https://en.wikipedia.org/wiki/1918_flu_pandemic
     
  10. Aug 24, 2015 #9
    https://en.wikipedia.org/wiki/Names_of_large_numbers
    With trillions or quadrillions 1015individuals organism I think math will win, not biology.
    7 billions for human,
    millions for elephants,
    hundreds of thousands for whales,
    and if an ant weight around 10 mg and the weight of all ants are heavier than human, there must be around 70 millions ants * 7 billions = 490 quadrillion, 1015 not including other insects and bacterias. With so many parameters the most successful viruses are the ones who compelled not to kill the host too early. Altough I don't know who "compels" them. God? Nature?
    Perhaps some viruses infect and kill their host before the host can spread it quickly, so they also vanish. Or there is someone dies from a strain of virus and we'll never know that strain because it also dies along with its host.
     
  11. Sep 3, 2015 #10

    Chronos

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    It has been suggested we may already harbor organims that have evolved to form symbiotic relationships with the host. They actually promote longevity of the host to maintain a favorable breeding environment. This is a very fine balancing act. An overpopulated host could be overwhelmed by its symbiots and different hosts would have natural variancess in their tolerance. Sort of like human infestations of earth. A certain number of humans are beneficial to the earths ecosystem, but, the law of diminishing returns begins to take over as the number grows excessive.
     
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