 They namely encompass the time-scale of the life of a single individual, the longer one on which a population can be characterized , the ecological one and at least four nested ones on which selection occurs.
<meaning-changed>  They namely encompass the time-scale of the life of a single individual, the longer one on which a population can be characterized , the ecological one and at least four nested ones on which selection occurs.
 They namely encompass the time-scale of the life of a single individual, the longer one on which a population can be characterized through its demographic dynamics, and at least four nested ones on which selection occurs.