Simple explanations of difficult biological concepts.

I retired seven years ago, but still believe that teaching could be made easier by repeated use of  simple models. For example in medicine each speciality e.g. pediatrics, geriatrics has its own approach. This is effective for the specialist, but difficult for the student who must migrate from one speciality to the other during his training, each time learning a different method. It would be a lot easier for them if the approach to the diagnosis and treatment of disease emphasized the similarities in these processes in all age groups and specialities (See for example: The ins and outs of respiratory distress syndrome in babies and adults. J R Coll Physicians Lond. 1994;28:24-33). I could not convince my peers to introduce this “object-oriented” approach. Oh well, that’s in the past. But now as I try to develop my blog on biology I find myself again reverting to the object-oriented approach when trying to explain biological processes. Thus today I want to introduce you to the “object-oriented” approach to teaching and learning.  It first explains simple and well-known processes e.g. filling or emptying a wash basin (input & output), or speed of flow through a straw  when drinking a milkshake (suction pressure, diameter of straw, viscosity). Then it expands these “objects” to explain factors influencing complex biological events e.g. temperature control  or blood flow.

I first encountered the wash basin scheme when two eminent scientists in the 60’s & 70’s used it to explain calcium and acid base balance. They did this by explaining the factors that would influence their input or output.  I realized that this model could be useful for understanding many other day-to-day medical problems. I adopted and adapted their ideas, and later added in the “milkshake model” to help simply analyze other problems related to flow e.g. circulation and ventilation. These two object-oriented models with variations dominated my approach to clinical work, research, and teaching for the rest of my career. Looks like wash basins and milk shakes may attempt a comeback on this blog!!

 click on image to enlarge

I will return to these  models repeatedly in the months to come e.g. temperature and fluid balance in desert animals.  However, I have in “trip tips” on the website just discussed the effect of spotlights on nocturnal animals. Thus I will first try to explain how adequate concentrations of vitamin A and retinol, essential for night vision, are maintained.

It is interesting to note that the painter Cezanne believed that complex images could be broken down to simple geometric forms (objects). He wrote “Treat nature by means of the cylinder, the sphere, the cone”. This philosophy can be recognized in his wonderful paintings.


Objects are also the key to understanding “object-oriented” programming languages. Thus the characteristics of an object are encapsulated within it e.g. a wash basin be coded as having e.g. an input and an output, and these characteristics will inherited  by all its “offspring” objects e.g. controlling the temperature of a room. Similarly if flow of water is programmed as an object all subsequent flow “offspring” e.g. blood flow, will inherit these characteristics.

So reduction of difficult concepts into simpler forms has been used in many fields. I believe it should be more commonly used in biology to make scientific concepts easier to understand for the general reader. Long live object oriented thinking!

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