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

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

AS level coursework essay: Use of CT scans in general health checks

Recently in the UK there has been a growth in private health care companies offering CT and MRI scans as part of general health checks. However, there has been some doubt as to whether thse are beneficial to healthy patients. Indeed that the suggestion of increased risk of cancer due the high radiation experienced has certainly raised suggestions as to whether the risks, if these are used regularly, outweigh the benefits for otherwise healthy individuals.

A sensitive topic as obviously these are very useful diagnostic tools and one wouldn’t want to frighten people from having scans if their doctor deems it important. Obviously the coursework criteria must be checked closely to see if this is a suitable topic and whether it provides enough for an essay. However, it just occurred to me as I was popping up the videos for CT scans and thought I would suggest it. Some useful links are below:

BBC news “Scan may increase cancer risk”

USA today report: Radiation from CT scans

AS coursework idea: golden rice

The issues surrounding the development of the genetically modified rice, golden rice, maybe a useful topic for the AS coursework essay. Rather than discussion of GM foods in general a look at this particular food, and the campaign and controls against it, provides a rich source of discussion. Golden rice has been modified to produce high amounts of vitamin A, a deficiency of which causes many deaths a year in the developing world:

“According to the World Health Organization, dietary vitamin A deficiency (VAD) causes some 250,000 to 500,000 children to go blind each year. Blindness and corneal afflictions are but indicators of more severe underlying health problems: more than half the children who lose their sight die within a year of becoming blind. VAD compromises the immune systems of approximately 40 percent of children under the age of five in the developing world, greatly increasing the risk of severe illnesses from common childhood infections.”

Golden Rice Project

However, the severe restrictions have been placed on the use of golden rice and, as of, writing it has not been allowed out of the lab as yet. Is the need for supplements via rice needed? Are there alternatives? Are the fears of introducing the rice into the general agricultural system justified? Do the benefits outweigh the potential risks?

To find out more follow the links below and watch the videos.

The Golden Rice Project

BBC news: Golden Rice

Articles from the Science journal (will need to pay for access)

Golden Rice: A dangerous experiment (from BanGMfood.org website)

Video 1: Excerpt from Channel 4 Animal Farm series (looking at genetic modification and tissue engineering, recommeded viewing). It is 5 minutes long and shows the techniques involved.

Video 2: Slideshow and commentary on golden rice. Gives a greater voice to those who are against the use of golden rice.