Material World , Radio 4′s weekly science show, is running a competition for anyone who has a scientific idea they want to investigate. A level students are eligible to enter, and if you are chosen you will be given help to develop your idea with assistance from top scientific researchers. Everyone has a scientific question they want to investigate! Why not enter this competition and develop yours?

We talked about how eye colouration is polygenic, meaning that more than one gene is involved. So there probably wasn’t a simple answer to the question!

Heterochromia iridum (having two differently coloured eyes) is caused by differing levels of pigmentation in the two eyes. This may be caused by an injury to the eye, which causes one eye to produce too much or too little pigmentation. This is called ‘acquired heterochromia’.

Heterochromia is also present in a number of inherited genetic conditions, such as Waardenburg’s syndrome. Such conditions are usually inherited as a ‘faulty allele’ of a gene, although each case is different (see here for a list of inherited genetic (congenital) disorders associated with heterochromia).

A third possibility is that during embryonic development a mitotic division went wrong. This resulted in an uneven distribution of chromosomes in the daughter cells. This diagram here shows how this could happen through a process called nondisjunction. The result is that some cells only carry one chromosome from a pair and thus only have one version of the gene. If these daughter cells go on to develop into eye pigmentation cells then they can express a recessive allele as they no longer contain the dominant allele. Thus one eye expresses the colour for the recessive allele whilst the other, having cells from a non-changed cell line, expresses the normal dominant allele.

There are a lot of ‘ifs’ in this route, but some cases of heterochromia are caused by this ‘mosaicism’.

David Bowie is famous for having two different coloured eyes. He got his, apparently, from being hit in the face during a fight. So now you know.

Seeing that most people in the world are intolerant to lactose after weaning, is lactose intolerance actually an illness of the digestive system or just the digestive system acting normally?

And finally, a link to a site that explains the difference between an allergy and an intolerance.

As the publisher states on the website:

“Biological Sciences Review is written for students.

Each 44-page issue of Biological Sciences Review explores key topics on the new AS and A2 specifications. Specially written for students, each issue is designed to stretch and challenge their understanding through thought provoking articles.

Regular columns will help students develop understanding and skills. These include:

* Upgrade, Chief Examiner Bill Indge offers invaluable advice to get ahead in exam preparation
* How Science Works, a core element of the new specifications, this new column looks at examples of the ways in which scientists work and the potential impact of their work”

The library stocks past editions of the magazine and will have a subscription for this year also, but you may wish to have your own copy to add to your notes. It’s good.

Proper science telly.

http://www.bbc.co.uk/programmes/b00m5w92

The field course is over for another year and, despite the sea fret that accompanied it, it was a resounding success. Let’s start at the beginning…

Danby Moor is a short drive from the field center and set the tone for the rest of the weekend. Despite the weather the students threw themselves into the task of studying moorland management. Random sampling of the vegetation at various stages of recovery from burning showed secondary succession on the moors. As this succession is never allowed to continue to the climax community of woodland we call the moorland a plagioclimax, forever frozen at the serial stage that most benefits its human owners. In this case a patchwork of heather which provides the food and shelter for grouse, and many other species of birds and mammals besides. The chi² statistical analysis showed variation in the vegetation between the three burn sites, although a more in depth investigation would be needed to confirm this observation.

Saturday morning started with invertebrate sampling using sweepnets and pooters. The dew on the grass did not help when the nets soon became soaked and most grass dwelling insects must have retreated to drier areas. Still we found a variety of insects, a few spiders, and even a dead mole (though not through use of the sweepnet of course!). The beating tray collected more invertebrates from the trees and the pooters were put to good effect again. And although we put out various traps without much success, I think the point was made that sampling mobile organisms can take many forms depending on the organisms being targeted.

So then the trip to Runswick Bay for rocky shore ecology. We started with mark-release-recapture of Dog Whelks on a section of the rocky shore. I didn’t quite expect to find so many, but 564 molluscs collected in 5 minutes is pretty good going. A few minutes later and each one had a white dot on its shell to identify it as having been caught. The whelks were released back into their environment to to mingle with their undiscovered cousins. We would return the next day to hunt them out again…

We sampled zonation on the rocky shore using an interrupted belt transect. To speed things up we used the ACFOR scale to record the abundance of the various seaweeds and counted the animals individually. Back in the lab the kite diagrams showed the distribution of the organisms on the rocky shore and the effect of the abiotic factors on zonation. A Spearmans Rank Correlation Coefficient statistical test showed a significant correlation between bladder wrack and distance from high tide, although there were enough anomalies in this correlation to question the validity of the data. More data is needed to increase confidence in this relationship.

The next day we ventured to Coatham Sands in Redcar for sand dune ecology. Clearly the lack of sleep was catching up with people as the usual enthusiasm for the mighty Marram grass was not evident in the group, despite one teachers clear admiration for its xerophytic adaptations. The aim was to find evidence of primary succession, which occurs as colonising organisms affect the abiotic environment allowing other organisms to grow and out-compete the original plants in an area. This should eventually result in a climax community of trees, but this does not happen in Redcar as the rear of the dunes is put to use as industrial land. Still, the science of succession was evident in this industrial landscape showing that nature persists in all but the harshest environments.

It should be noted that the final evening’s rounders match saw a convincing win for the Snape-Haye team against the frankly disappointing Howell-Eastwood team. Clearly better biologists than rounders players, the returning sea fret was a suitable excuse for a poor batting/fielding display.

All, then, was over apart from the write-up on the last morning. This took the form of a sand dune profile  and line graphs showing how species changed along the dune. This representation of the data showed patterns of distribution more clearly than tables of data could, and was worth the effort I think.

So what do you learn on a biology field trip? The process of succession and effects of abiotic factors, the reasons for zonation on the rocky shore and the associated change in plant and animal life, the different methods of animal sampling and the limitations of these, the use and application of statistical testing to make sense of data that does not fit a perfect pattern. All of this. And also that Biology is the study of life, and life has to be investigated where it is found. Outside. Where sometimes it is wet, and sometimes it has sharp edges, but more often than not it is simply stunning.

Thanks to the students for making the trip so successful, the field centre for providing us with great accommodation and fantastic local knowledge, and the teachers who put so much effort into making this weekend a success.

On the field course we will be sampling grassland invertebrates, rocky shore organisms, sand dunes vegetation and potentially mammals (if we can trap any!). To do so ethically requires planning. The following organisations have codes of conduct for fieldwork. Take time to read them.

The Marine Conservation Society seashore code

The Wild Flower Society code of conduct

The Amateur Entomologists’ Society code of conduct for collecting insects and other invertebrates.

Discovering the beauty of  natural habitats is one of the best things about being an ecologist. We need to do our best to leave our study sites, and the animals living in them, in the best, most natural, state possible.

This years field course is fast approaching. 26th to 29th June 2009.

All students planning on continuing into A2 are expected to attend the field course. Fees need to be paid by 19th June at the latest, so if you have paid your deposit you need to get the final installment in by the end of next week. If you have yet to pay anything, you can pay in full by the 19th June. If you think there will be problems finding the money, or problems attending the course, you must speak to a member of the Biology team as soon as possible so that we can make arrangements.

This years course has been redesigned to suit the new specification so you can be sure that what we cover in the field will be useful in the exam hall in January.

It will also be fun and, I’m assured, it will be sunny also!

Maybe…