[Martin]

Martin asked the Naked Scientists:
   
What are the seven criteria for defining life?

What do you think?

[CliffordK]

There are seven criteria?  Sounds like a quiz question.

Ok, I think I'd start with:

1) Self Reproduction.
2) Some kind of energy conversion
3) Some kind of chemical or matter conversion
4) Some kind of containment, or boundaries.

Hmmm,
So, I've gotten 4.
Do I really need 3 more criteria?

One can certainly describe terrestrial prokaryotes and eukaryotes.  But, in many senses, one needs a definition that would extend to Life in general.

Viruses and Phages are always troubling as they may share some characteristics or other living organisms, but they are unable to perform cellular functions without a host cell which performs most of the tasks of life.

One also has problems like if one asks whether FIRE is alive?

[Airthumbs]

The exact list you are looking for is here;  http://en.wikipedia.org/wiki/Life

[cheryl j]

In some textbooks the criteria for life are:
self reproduction
metabolism
organization
response to stumuli

[Mazurka]

In some textbooks the criteria for life are:
self reproduction
metabolism
organization
response to stumuli

Oh no,  that suggests that some of my colleagues - who lack both organisation and seldom respond to stimuli - are not alive!