Nothing in Biochemistry Makes Sense Except in the Light of Evolution

The title of this post is a slight paraphrasing of Theodosius Dobzhansky's famous saying, "Nothing in Biology Makes Sense Except in the Light of Evolution. That was the title of an article he published in American Biology Teacher and that's significant since the main point was to convince teachers that evolution is important.

What applies to biology also applies to biochemistry. Evolution should come up in many places in a typical biochemistry course. The most obvious place is when we teach comparisons of nucleotide and amino acids sequences and the construction of phylogenetic trees. Students have to know the underling concept behind these comparisons. The have to know why some sequences are conserved (negative selection) and why some sequences are variable (fixation of neutral alleles by random genetic drift).

But this isn't the only place where evolution is important. How can you explain why humans need vitamin C and "essential" amino acids without mentioning evolution? How can you teach biochemistry without covering the evolution of biochemical pathways? How do you explain the existence of a complex process like the membrane-bound photosynthesis complexes in chloroplasts without showing how it evolved from simple bacterial examples? Who teaches the information flow section of the course without starting with E. coli and working toward the more complex eukaryotic examples? How do you explain why animals need glucose when most species don't need an external supply of complex carbohydrate? How do you explain why gluconeogenesis is a more primitive pathway than glycolysis? Why are comparative genome studies important in working out metabolic networks? Why does "homology modeling" work?

The American Society for Biochemistry and Molecular Biology (ASBMB) is trying to set up a certification scheme for biochemistry programs in America. The idea is that universities and colleges that meet certain standards would receive a stamp of approval from ASBMB. There would be a nation-wide exam for graduating students and if they pass the exam they get a sort of "certification" that proves they have the minimum skills and knowledge to take jobs that require these skills.

The trick is to define the common skills and knowledge that are needed. I attended two sessions at EB2013 where these criteria were discussed. One was a presentation by the committee in charge followed by some discussion: "ASBMS Certification Program for Bachelor's Degrees in Biochemistry Molecular Biology and Related Majors." The questions in this session were focused on how to get certified and not on what was in the proposal.

The other session was "Promoting Concepts-Driven Teaching Strategies in BMB Through Concept Assessments" but, as it turned out, there was very little chance to discuss the concepts that were being assessed.

You can read the current draft proposal by clicking on the link at ASBMB Degree Certification Program in Biochemistry and Molecular Biology. You might be interested in finding out what a department needs to do in order to be certified.

I'm more interested in what biochemists have to teach. Here's the relevant section ...

Core Concepts and Learning Objectives

An ASBMB-recognized program should be able to relate each element of its BMB curriculum to one or more of the core concepts listed below and their related learning objectives (For reasons of space, sample learning objectives are provided in Appendices II – V):

1. Energy is Required by and Transformed in Biological Systems.
2. Macromolecular Structure Determines Function and Regulation
3. Information Storage and Flow Are Dynamic and Interactive.
4. Discovery Requires Objective Measurement, Quantitative Analysis, & Clear Communication.

The curriculum should present these core concepts in a manner that illustrates the pervasive role that Evolution plays in shaping the form and function of all biological molecules and organisms.

That last sentence is new to me. I've never seen it on any of the slides shown at either of the meetings I attended (EB2012 and EB2013).

It's a welcome addition. But, since most biochemistry courses in America are taught out of Chemistry Departments, I wonder if this will make certification more difficult.

Finally, I can't help but insert a plug for my book. It's the only biochemistry textbook that presents the subject from an evolutionary perspective and it's certainly the only textbook where the pervasive role of evolution is emphasized in every chapter.

The next step will be to help the organizing committee refine and upgrade the "Learning Objectives" for each of the core concepts. These are given in four appendices in the draft document.

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Dobzhansky, T. (1973) Nothing in biology makes sense except in the light of evolution. American Biology Teacher 35:125-129.