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2.5: The Death of Vitalism

Naturalists originally thought that life itself was a type of supernatural process, too complex to obey or be understood through the laws of chemistry and physics.38 In this vitalistic view, organisms were thought to obey different laws from those acting in the non-living world. For example, it was assumed that molecules found only in living organisms, and therefore known as organic molecules, could not be synthesized outside of an organism; they had to be made by a living organism. In 1828, Friedrich Wöhler (1800–1882) challenged this view by synthesizing urea in the laboratory. Urea is a simple organic molecule, (\(O=C(NH_2)_2\)) found naturally in the waste derived from living organisms. Urinecontains lots of urea. Wöhler's in vitro or in glass (as opposed to in vivo or “in life”) synthesis of urea was simple. In an attempt to synthesize ammonium cyanate (\(NH_4NCO)\), he mixed the inorganic compounds ammonium chloride (\(NH_4Cl\)) and silver cyanate (\(AgNCO\)). Analysis of the product of this reaction revealed the presence of urea. What actually happened was this reaction:

\[\ce{AgNCO} + \ce{NH_4Cl} \rightarrow NH_4NCO + AgCl \rightarrow \ce{O=C(NH_2)_2} + \ce{AgCl}\]

Please do not memorize the reaction, what is of importance here is to recognize that this is just another chemical reaction, not exactly what the reaction is.

While simple, Wohler’s in vitro synthesis of urea had a profound impact on the way scientists viewed so called organic processes. It suggested that there was nothing supernatural involved, the synthesis of urea was a standard chemical process. Based on this and similar observations on the in vitro synthesis of other, more complex organic compounds, we (that is, scientists) are now comfortable with the idea that all molecules found within cells can, in theory at least, be synthesized outside of cells, using appropriate procedures. Organic chemistry has been transformed from the study of molecules found in organisms to the study of molecules containing carbon atoms. A huge amount of time and money is devoted to the industrial synthesis of a broad range of organic molecules.

Questions to answer and to ponder:

  • Generate a scheme that you could use to determine whether something was living or not.
  • Why does the continuity of cytoplasm from generation to generation matter? What (exactly) is transferred?
  • Why did the discovery of bacteria reopen the debate on spontaneous generation?
  • How is the idea of vitalism similar to and different from intelligent design creationism?
  • Is spontaneous generation unscientific? Explain your answer.

References

38 In a sense this is true since many physicists at least do not seem to understand biology.

Contributors

  • Michael W. Klymkowsky (University of Colorado Boulder) and Melanie M. Cooper (Michigan State University) with significant contributions by Emina Begovic & some editorial assistance of Rebecca Klymkowsky.