Thursday, September 22, 2011

On My Mind......Form and Function

By:  Ken Kozar

I've been thinking a lot about form and function lately.  Our kids are building all sorts of things like marshmallow towers and chairs and I keep hearing Sean say that form follows function.  Kids are designing wiki seats but are first describing what function they want their chair to serve.  The design or form of their chair then follows. 

Form follows function is a long-standing principle associated with modern architecture and industrial design in the 20th century.  The principle is that a shape of a chair, building, marshmallow tower, etc should be primarily based upon its intended function or purpose.  But.....does this long-standing principle apply to biology and biological systems?  We've all heard it before in biology..."form fits function".  Meaning, an organism is designed or structured in a way that will help it perform a certain function.  Lets look at a couple examples.

Jean-Baptiste Lamark's discredited theory of evolution states that an organism's anatomy is structured according to functions associated with use, in other words, the "theory of use and disuse".  For example, a giraffe possesses a long neck in order to reach leaves high up in trees.  By contrast, Charles Darwin stated that form precedes function as determined by natural selection.  Lamark - form is altered by function and Darwin - variations in form allow parts t function "better".

Proteins are macromolecules that fold into very precise 3-dimensional shapes.  This shape will ultimately determine its function.  Smaller subunits or monomers called amino acids link together to form proteins.  There are 20 naturally occurring  amino acids that can link together to form a dizzying array of combinations to form proteins.  These amino acids possess a variety of chemical and physical properties.  Each sequence gives the protein a unique profile along its chain.  This profile then determines how the protein folds and ultimately interact with other proteins to form complexes that are crucial to our survival.  Hence, the amino acids sequence (form) ultimately determines its function,  since the amino acid sequence determines the structure and structure determines function.

So I ask you......does this long-standing principle of "form follows function" fit biology or is it the other way around?

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