"Nothing in Biology Makes Sense Except in the Light of Evolution" - Theodosius Dobzhansky
There is grandeur in this view of life, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.
Trying to figure out the rules from fragments here and there...
do leftover resources carry over from round to round?
yes, and saving up resources can be a key strategic consideration