The needs of the same human being may differ at different stages of life. Can there be one Dharma for all stages?
Is there one dharma preaching for all stages of life (or stages of evolution) in Buddhism? or are there many?  


There are many dharma preachings relevant to life stages.

Buddhism teaches Five Niyamas 

In Kamma Niyama, it says every action has reaction. So don't do to others what you dislike.