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.

IGCSE Biology: Skin and insulation coursework investigation

Most, if not all exam boards, require students to design, implement and evaluate their own investigations. For Cambridge IGCSE this is assessed by the practical skill C4. A popular coursework experiment for C4 in IGCSE Cambridge is for students to design an practical that models insulation adaptation in animals as there are a wide variety of choices.

Some may compare heat loss between a 100cm3 measuring cylinder (tall and thin or high surface area:volume ratio) and a 100cm3 beaker (short and fat or low surface area to colume ratio). Other students may choose to simulate clothing or fur by adding layers of clothing or wool to test tubes. Investigating huddling with many testubes surrounding one test tube as compared to one lone test tube is also popular as it can always be introduced with the segment from the Life in the Freezer video showing the emperor penguins in the Antarctic.

Another possibility is to investigate the role of fat as an insulating layer in skin. This relates directly to comparing adaptations as well as it is possible to talk about the fat layers laid down by seals etc. This practical simply involves pouring a layer of cooking oil onto the surface of some hot water and comparing the heat loss with a similar beaker of hot water that does not have the oil. I have tried this experiment with both Year 9 and 10 and it works very well. The beauty of this experiment is that the intial simple version can be used as an introduction for studnets to extend it to investigate the effects of different anounts of oil (and perhaps different types). Again I have tried this out and it does show a correlation adding up to 20cm3 of oil in 5 cm3 increments. Unlike many of the experiemnts suggested above this allows students to have a continuous variable to graph and so can be more challenging to analyse whilst being easy to design.

I have added the worksheets below which have the intial introductory practical and the practical design set as homework. It is in Word so is easy to modify. My colleague has used this experiment as a C4 training excersise for the Year 10 students and developed a short checklist to help them write their evaluations. I have added this as well.

Worksheets:

Investigating Skin Structure and Function

Coursework evaluation

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

AS Biology Coursework Idea: Hebridean Hedgehogs

Here is another good topic for the AS essay. Hedgehogs, originally introduced as a biological control, have themselves become a pest. Lots of prickly issues around whether to cull or relocate. Again from the Guardian Environment pages:

Hebridean Hedgehogs: A prickly issue

AS Biology coursework idea: Asian “Terminator” Carp

Asian carp are an invasive species in the American Great Lakes that is causing widespread devastation to the indigenous species. Below is a link to an article in the Guardian (and scroll down for other associated links) plus an audio file.

News article: Terminator Carp

Audio:

gdnenv100224tmed-pilkington