Particles Behaving Strangely

I’m trying to follow a Blender Cookie tute on hair, and my particles seem to be behaving differently to the tute.

i’ve selected the end of a hair strand and grown teh selection, but when i comb the stuff around, particle joints i haven’t selected are moving too and that didn’t happen in the vid.
also, my display is showing disembodied joints :

this is actually from the strand beside it - it you grow the selection you can see :

is there some settings i’m missing, or something?