Hiya, I'm trying to write some revision notes on this topic at the moment and I'm a bit confused as to what it is that we actually need to know. Do we need to know about segementation in drosophila and development in vertebrates etc? There's info on these topics in Scholar and the monograph, but the actual learning outcomes are a bit vague. In the notes next to this topic it just says ".....cellular differentiation depends on changes in gene expression resulting in genes being switched on and off (similar depth of treatment to Higher Biology)". Now I did Human Biology, but I'm guessing that in Higher Bio you didn't cover drosophila etc? Any help would be much appreciated!