Peter writes:
>Harold Morowitz' forthcoming book, "Metabolism Recapitulates
>Biogenesis: The Beginnings of Cellular Life" has a succinct definition
>of living systems. To paraphrase from a draft of the book, an
>autonomous biological self-replicating system is a molecular
>self-replicating entity that is capable of evolving, and that operates
>in the absence of other self-replicating entities. Therefore, a virus
>is not an autonomous biological self-replicating system because it
>requires the presence of other self-replicating entities to replicate.
>Whether it is alive or not depends on whether you equate life with an
>autonomous biological self-replicating system, or simply a biological
>self-replicating system.
This definition of life does exclude many symbiotic organisms, such as
the malaria parasite and others, which require host organisms to
complete their life
cycles . . .
Joanne
