Naked Science Forum

Life Sciences => Cells, Microbes & Viruses => Topic started by: colarris on 27/07/2010 12:40:00

Title: Why haven't viruses taken over this planet?
Post by: colarris on 27/07/2010 12:40:00
 Why haven't viruses taken over this planet? Some still we still have no defence against and I|'m surprised they are not the most dominant organism on Earth.
Title: Re: Why haven't viruses taken over this planet?
Post by: Variola on 27/07/2010 13:06:56
What makes you thin they haven't? Virtually all living organisms have their own set of viruses, even bacteria and other viruses do. I'd day they had pretty much overtaken the planet!  [:)]
Title: Re: Why haven't viruses taken over this planet?
Post by: colarris on 27/07/2010 20:29:31
Have germs been around ever since simple life began? If they have I'm suprised they never killed it off before it evolved further.
Title: Re: Why haven't viruses taken over this planet?
Post by: Variola on 27/07/2010 21:42:02
Have germs been around ever since simple life began? If they have I'm suprised they never killed it off before it evolved further.

Yep prokaryotes have been around since before humans evolved :-) We have evolved to live with them, hence our immunce system is well adapted to fight off most infections that we encounter.
In the majority of human cells, there are mitochondra, organelles that supply the cell with the energy it needs to carry out its function. It is thought, based on good evidence that these mitochondria were once free living bacteria, that got swallowed up pac-man style by a eukaryotic cell. From that they developed a symbiotic relationship in that the mitochondria provide the energy to the cell and in return they get protection. Choroplasts in plant cells have been thought to have originated the same way.
Nowadays mitochondra are replicated and made along with the cells themselves.
Title: Re: Why haven't viruses taken over this planet?
Post by: colarris on 27/07/2010 23:21:44
Many thanks Variola. The more I learn about biolgy the more unbelievable it all seems! :s
Title: Re: Why haven't viruses taken over this planet?
Post by: colarris on 28/07/2010 12:01:46
One more thing. Have germs remained unchanged since creation of have they involved like every other life form?

 Appreciate your replies. :)
Title: Re: Why haven't viruses taken over this planet?
Post by: imatfaal on 28/07/2010 17:30:55
Others may correct me and/or amplify; but I think bacteria change very quickly.  as an example; various bugs that cause infectious diseases have become immune to the antibiotics that we have created to combat them.

  every time each of us takes a course of anti-biotics (and especially if we don't finish the course) we are left with a tiny number of bugs that have survived; generation upon generation and infection after infection this leads to a species-wide immunity to the anti-biotic in question.  in the last few decades, through inadvertant selective breeding, we have created bacterial strains with evolved immunity to multiple anti-biotics.

i see no reason why they shouldn't be evolving in many other manners that are not so readily apparent.

Matthew
Title: Re: Why haven't viruses taken over this planet?
Post by: Variola on 28/07/2010 19:03:49
Many thanks Variola. The more I learn about biolgy the more unbelievable it all seems! :s

Yeah it is pretty special :-)
Others may correct me and/or amplify; but I think bacteria change very quickly.  as an example; various bugs that cause infectious diseases have become immune to the antibiotics that we have created to combat them.

  every time each of us takes a course of anti-biotics (and especially if we don't finish the course) we are left with a tiny number of bugs that have survived; generation upon generation and infection after infection this leads to a species-wide immunity to the anti-biotic in question.  in the last few decades, through inadvertant selective breeding, we have created bacterial strains with evolved immunity to multiple anti-biotics.

i see no reason why they shouldn't be evolving in many other manners that are not so readily apparent.

Matthew

It is important to remember that the antibiotics we use are made by or originate from bacteria or fungus themselves, hence they already have the genes within them to be resistant to it, otherwise making antibiotics would be suicide. The only ways we have found to combat this are by discovery of novel antibiotics, again in fungi or bacteria, or by modifying the antibiotics we already have. Bacteria in the same family as other antibiotic-producing bacteria often have the resistant genes too, for example Streptomyces Coelicolor has Vancomycin resistant genes encoded into its genome. This is simply because it is an actinobacteria, the same family of bacteria that produces Vancomycin  Amycolatopsis orientalis
Title: Re: Why haven't viruses taken over this planet?
Post by: sittingoverhere on 09/08/2010 01:42:09
Why haven't viruses taken over this planet? Some still we still have no defence against and I|'m surprised they are not the most dominant organism on Earth.
The best estimate I can find is that there is somewhere between 1 x 1030 and 5 x 1030 bacteria on this planet and viruses outnumber bacteria 10:1. Whilst I wouldn't say they are 'dominant' they are certainly numerous.
Title: Re: Why haven't viruses taken over this planet?
Post by: DoryT on 09/08/2010 06:41:08
We live in a virus-ruled planet, not a humans-ruled one, aren't we?
Title: Re: Why haven't viruses taken over this planet?
Post by: colarris on 09/08/2010 22:34:06
No wonder aliens stay clear! :)
Title: Re: Why haven't viruses taken over this planet?
Post by: DoryT on 12/08/2010 06:18:16
No wonder aliens stay clear! :)
Amen! Though I'm sure they would come with their own biospherical breathing equipment....if they even need to breath!