Life aye! Who's bloody idea was that? Bet they've sodded off back home laughing.
"Lets have 2 similar but completely opposite creatures, then have them not understand the other EVER! No matter how many centuries the live together, cohabiting and studying each other.
THEN lets make all the life forms on the rock breathe in oxygen but breathe out poison, then have the plants and trees breathe in the poison and breathe out oxygen. That way the trees will be safe.
To stop overcrowding will we make their bodies fail and decay from the moment of birth, then for good measure we'll throw in an incurable disease from time to time. Or a 'natural' disaster.
Now lets give our 2 creatures different skin shades and belief systems and values; that way it would be easy for them to create unnecessary conflict and hurt each other.
Last but no means least, lets give them emotion and thought. Now, for every one that cares; there will be one that don't care. For every one that thinks he's right, there will be another one that thinks HE'S right.
Put them all together on a little spinning rock in space, and call it "Life'"