Definition of life (fwd)

MJ Duggan sgex400 at sghms.ac.uk
Wed Feb 9 07:35:22 EST 1994


Ricard Streng wrote
> 
> >What about circulating red blood cells, without nucleus? Aren't they alive?
> 
> Red blood cells of mammalia without a nucleus aren't alive in the
> sense of my definition. Such a cell is merely a part of a living
> system which is still able to fulfill some functions for a limited
> time period.

I quite agree.

> 
> Hubert Martin Sauro in this newsgroup actually gave a similar
> definition.
> 
> Generally we have to discriminate between two sights by a definition
> of life.
> 1. We mean a complete organism (with its ability to reproduce), or
> 2. we mean any part of the organism downto a single cell of it.
> 
> I think that some assimilation processes within cells which have a more 
> or less diminuated genetic information (as in a lot of somatic cells)
> are not sufficient to define life. A definition of live should have
> in mind that only by reproduction any evolution can occur.
> 
> Well, if one asks me whether a freshly plucked flower is alive or
> not, I would like to say yes. But the answer is in that second mode of 
> view.
> 

But if the floweer is capable of pollination and even of (after being placed
in a  vase) producing viable seeds then is it not alive? Following from this
are gametes alive, whether they are sperm or oocytes or pollen, in that they
have  the ability to reproduce, under certain rather special circumstances.

Mike Duggan




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