reply to post by GradyPhilpott
I agree. We have to conclude that Biology, if that's the acting force, finds many solutions to the same problem here on Earth.
One way to put it might be that certain traits -seem- to be favored, and the dominant forces applied to carbon-based life
3. conditions (gravity, pressure, temperature; land/sea/air)
5. other minor forces
From what we know, bilaterally symmetrical, medium sized, tool users would seem to be a requirement, though hive-based life could also be viable,
which means all bets are off, eh?
The needs that must be addressed are probably similar
1. locomotion, propulsion;
3. food gathering;
4. assimilation and excretion;
5. social interaction, both -intra and -extra species;
6. individuation (however, one could even imagine a Gaia-based life form that was one entity, planetwide, or a hive mind).
Older definitions of 'life' include terms such as 'homeostasis, organization, growth, adaptation, response to stimuli, and reproduction. But this
excludes asexual organisms, viruses and prions, for example (taken from Wiki, see below)
sums up what 'Life' entails quite nicely:
Proposed definitions of life include:
1. Living things are systems that tend to respond to changes in their environment, and inside themselves, in such a way as to promote their own
2. Life is a characteristic of self-organizing, self-recycling systems consisting of populations of replicators that are capable of mutation,
around most of which homeostatic, metabolizing organisms evolve.
However it might be easy to miss a live organism if their life is on a timescale unfamiliar to us, such as a slow moving, geological time based
All this should lead us to conclude that though a few forms might seem to be favored, there are a -very- wide array of possible solutions.