BBC 1 drama is mainly on at 9 o'clock with a various range of shows like sci-fi Doctor Who, and and more serious shows like casualty so some aimed at like the whole family and some aimed at just adults playing the family one before.
BBC 2 drama is mainly on at 7:30 - 9:00 mainly crime dramas so more just hospital and cop shows. aimed at mainly adults like Luther because of the type of shows some children may like it like thunder-birds.
BBC 3 is mainly sci-fi and fiction and comedies mainly series.I think this is aimed at mainly teens aged between 16-35 shows like Atlantis