How the EES differs from the Modern Synthesis

Like the EES, the Modern Synthesis also represents a particular way to understand evolution. It primarily focuses on genes:

 

  • new variation arises through random genetic mutation
  • inheritance occurs through DNA
  • natural selection of genes is the sole cause of adaptation

 

The field of evolutionary biology has evolved, incorporating many new theoretical and empirical findings (e.g. neutral theory, inclusive fitness theory). As a result, today’s evolutionary theory is vastly more sophisticated than the original modern synthesis, which emerged in the 1940s-1960s, and covers a broader range of phenomena. Nonetheless, the most prevalent expectations remain broadly in line with those emphasized by the founders of the modern synthesis, and are distinct from EES predictions.

 

Click on an EES prediction to view research projects designed to test it.

 

 

Traditional predictions

EES predictions

  1. genetic change causes, and logically precedes, phenotypic change, in adaptive evolutionphenotypic accommodation can precede, rather than follow, genetic change, in adaptive evolution
  2. genetic mutations, and hence novel phenotypes, will be random in direction and typically neutral or slightly disadvantageousnovel phenotypic variants will frequently be directional and functional
  3. isolated mutations generating novel phenotypes will occur in a single individualnovel, evolutionarily consequential, phenotypic variants will frequently be environmentally induced in multiple individuals
  4. adaptive evolution typically proceeds through selection of mutations with small effectsstrikingly different novel phenotypes can occur, either through mutation of a major regulatory control gene expressed in a tissue-specific manner, or through facilitated variation
  5. repeated evolution in isolated populations is due to convergent selectionrepeated evolution in isolated populations may be due to convergent selection and/or developmental bias
  6. adaptive variants are propagated through selectionin addition to selection, adaptive variants are propagated through repeated environmental induction, non-genetic inheritance, learning and cultural transmission
  7. rapid phenotypic evolution requires strong selection on abundant genetic variationrapid phenotypic evolution can be frequent and can result from the simultaneous induction and selection of functional variants
  8. taxonomic diversity is explained by diversity in the selective environmentstaxonomic diversity will sometimes be better explained by features of developmental systems (evolvability, constraints) than features of environments
  9. heritable variation will be unbiasedheritable variation will be systematically biased towards variants that are adaptive and well-integrated with existing aspects of the phenotype
  10. environmental states modified by organisms are not systematically different from environments that change through processes independent of organismal activityniche construction will be systematically biased towards environmental changes that are well suited to the constructor’s phenotype, or that of its descendants, and enhance the constructor’s, or its descendant’s, fitness
  11. parallel evolution explained by convergent environmental conditionsrepeated evolution in isolated population may be due to niche construction
  12. ecosystem stability, productivity and dynamics explained by competition and trophic interactionsecosystem stability, productivity and dynamics critically dependent on niche construction/ecological inheritance
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