Daphnia-Caffeine experiment alternative

If you are working abroad then it can be a big problem trying to complete the core practicals included in the Edexcel A Level syllabus. At the moment I am having a lot of difficulty obtaining simple bacteria and in the past it has been impossible to get daphnia shipped internationally.
One alternative to using daphnia to observe the effects of caffeine on heart rate is to use mosquito larvae.
My colleague picked this tip up on a recent exam review session in Madrid. He tried it out and found that it was easier to do than with daphnia, both the heart beat could be counted (and it is slower than daphnia)and a large blood vessel could also be observed pulsating. In hot countries it should be fairly easy to get hold of the larvae from any area of still water.

A2 Biology Level coursework help sheet and presentation

When I set the coursework for my students I always review the markscheme carefully. I used to print it off and hand it to them but I suspect they never really read them through. Hence I have done a shorter version (2 pages) that simply recaps the main requirements and the higher range marking guidelines. In addition there is a brief PowerPoint presentation reviewing the markscheme. All of these are deliberately short as I do want to keep the students focussed and not overload them with too much information.

worksheets:

a2-biology-individual-investigation-summary

Teacher presentation:

coursework-assessment