Say I have three unicellular organisms: a eukariote, a bacterium
and an archaeon. If I cut off nutrition from them at the same
time, how long will it take for them to die? What will their
death look like, and do they actually need to die? If so, why?
This is very dependent on the organism within each of the groups
you mention. While for the most part, archea are the
extremophiles and have the ability to withstand many extreme
conditions, nutrient limitation survival greatly varies. I think
you could easily find organisms in each group that could
withstand nutrient limitation well. A good example would be
yeast, which is a single celled organism you may have actually
worked with. If you take laboratory yeast, in their diploid
state, and starve them, they will undergo meiosis, and in their
spore form, live for a very very long time without nutrients,
protected by their ascus (which is actual their dead mother
cell). Yeast can also completely desiccate and still live. When
you pick up an active yeast packet for