Some evolutionary papers are filled with verbs like arose, emerged, and originated.  Do these convey scientific understanding, or are they veils concealing ignorance?  Is it like saying “abracadabra” to say something “arose” by evolution?  A recent paper about sophisticated metabolic enzymes in plants is a case in point.

In a paper by Weng, Philippe and Noel in Science (29 June 2012: Vol. 336 no. 6089 pp. 1667–1670; DOI: 10.1126/science.1217411), the magic starts right in the title: “The Rise of Chemodiversity in Plants.” It rose to a crescendo throughout the overture to evolution’s uncanny power to bring things forth out of nothing.1  In the following excerpts, the magic words, hedging words and personifications are highlighted in bold:

  • The Emergence of Metabolism
  • New metabolic branches continuously arose throughout land-plant evolution.…
  • Since its origin as a fundamental property of the cell, metabolism is generally regarded as having evolved toward increasing order and catalytic efficiency.…
  • Primary metabolism likely arose from promiscuous primeval metabolic reactions and evolved toward greater catalytic precision and efficiency. Specialized metabolism likely emerged from primary metabolism.
  • Even deleterious changes appearing in one paralog may be tolerated and not eliminated by selection, when the other paralog contributes to fitness. In such cases, the evolution of advantageous activities can now be favored in new environments.
  • .…increased catalytic promiscuity likely molded the evolution of specialized enzymes.
  • Once a duplication-derived progenitor emerged, mutations may have loosened the energetic interdependencies.…
  • For instance, the evolution of rosmarinic acid biosynthesis in Lamiaceae herbs arose from gene duplication of a BAHD acyltransferase.
  • The emergence of rosmarinic acid synthase (RAS) in Lamiaceae likely followed substrate permissiveness of its evolutionary progenitor HCT, a more conserved enzyme ubiquitous in land plants….

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