Mario Vaneechoutte wrote:
> Alexei Sharov wrote:
>
> > Continuing discussion with of Mario Vaneechoutte:
> >
> > >> >> Genes use cell machinery for self-replication in the same way as
> > >> >> viruses do. Or may be you don't consider viruses replicators?
> > >> >
> > >> >Viruses can only exist because there are cells. They are replicated by
> > >> >cells.
> > >>
> > >> But viruses have their own goals and meanings; in this sense they are
> > >> autonomous and alive. If you think that viruses are not replicators,
> > >> then all parasitic organisms are also not replicators because they
> > >> require a living host to live in. They can not replicate themselves
> > >> without a host. Do you accept this? May be you consider replicators
> > >> only autotrophic organisms?
> > >
> > >The difference is that viruses are informational parasites. The replication
> of
> > >their genome has to be done by other organisms. Other parasites have their
> own
> > >replication machinery, and depend on hosts for metabolic reasons only. Just
> > >like any organism (except a few bacterial species) relies on others for its
> > >metabolism. After all, predation (eating other organisms) is an extreme
form
> of
> > >parasitism.
> >
> > Mario, you have not answered my question. I don't mind if you can call
viruses
> > informational parasites. The questions are: are they replicators and
> > are they alive?
>
> They are not replicators: they depend on the gene replication machinery of
other
> organisms for the replication of their genes.Other parasites do not. Other
> parasites
> depend only for metabolism on other organisms, having their own replication
> machinery.
>
> Are they alive? They do not have metabolism, so what?
> Am I alive? I have metabolic funtions, so what?
> I am part of a 4 billion year old organism which is a trillion, trillion, ...
> billion cells large. Isolate me (or any other 'living organism' or a virus)
from
> the
> rest of this organism and processes in my body (or the replication of the
virus)
> will soon stop. You can not answer the question of what life is by studying a
> single
> living organism. Life as we now it is the metabolic network formed by all the
> descendants of that first cell. I think that when you can explain the origin
of
> the
> first cell, that the rest of the explanations follows.
> Viruses are part of the organism Life, but asking whether they are alive is
the
> wrong kind of question I believe, just the same as asking whether I am alive.
>
> >
> >
> > There are many other cases when host-parasite relationships
> > involve interpretation of signs. For example, some insect parasitoids
> > release host hormones which are interpreted by the host. Without
> > this interpretation parasitism will not be successful and there
> > will be no self-reproduction of the parasite.
>
> OK. But this kind of interaction happens not only between host and parasite,
it
> happens continuously between all kinds of organisms. We influence each others
> metabolism all of the time. I do not see the relevance.
>
> Mario