Viruses are alive because they EVOLVED from living organisms? I think we need
a definition of organism here:
"An organism is the unit element of a continuous lineage with an individual
- Salvador Luria, JE Darnell Jr, David Baltimore & A Campbell; General
Virology, 3rd Edn.
People all too often think of life in terms of a"top-down" approach: going from
things with legs or leaves to less complex forms, until they reach viruses and
say: "hey, these things are just molecules, anyway!"
"A material is living if, after isolation, it retains a specific configuration
that can be reintegrated into the cycle of genetic matter."
- Salvador Luria, 1953 (Virology, 1st Edn)
Prescient, wouldn't you say? And describes viruses as organisms as life,
succinctly and aptly.
It is quite possible that many viruses evolved from cellular organisms (not
living orgs); it is equally possible that there are some viruses around now
which descend from bits of nucleic acid that may have been part of the very
first self-replicating (acellular) systems - some of the simpler (not
primitive) RNA viruses or parts thereof are very good candidates for direct
linear descendants of the ancestral RNA molorgs (molecular organisms).
And who's Una, anyway? And why does she get so cranky when people try to show
a bit of respect by calling her Ms? Methinks the lady doth protest too much.
| | |
| Ed Rybicki | Now you've got the hang of it |
| Dept Microbiology | There's nothing you can't do with it |
| University of Cape Town | If you're very into it |
| PB Rondebosch 7700 | You can't go wrong.... |
| South Africa | |
| fax 27 21 650 4023 | - Mad John |
|ed at micro.uct.ac.za | (Ogden's Nut-Gone Flake, Small Faces) |