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Homology and misdirection.

James S Farris1,2,3

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|November 13, 2021
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Summary
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The study argues that symplesiomorphies should be considered homologies, aligning with historical evolutionary concepts. It critiques modern phylogeneticists who exclude symplesiomorphies, advocating for a return to Hennig's original definition of homology.

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Area of Science:

  • Systematic Biology
  • Evolutionary Biology
  • Phylogenetics

Background:

  • The definition of homology has been debated in evolutionary biology.
  • Willi Hennig's work in 1966 considered symplesiomorphies as homologies.
  • A contrasting view emerged in 1981, seeking to exclude symplesiomorphies from homology.

Purpose of the Study:

  • To re-evaluate the concept of homology in phylogenetic systematics.
  • To address the ongoing debate regarding the inclusion or exclusion of symplesiomorphies in homology.
  • To advocate for the logical consistency of Hennig's original definition of homology.

Main Methods:

  • Analysis of historical definitions of homology.
  • Critique of modern phylogenetic terminology and its logical underpinnings.
  • Examination of the concept of homology versus synapomorphy in cladistics.

Main Results:

  • Hennig's recognition of symplesiomorphies as homologies is logically sound under the historical concept of homology.
  • The exclusion of symplesiomorphies by some phylogeneticists lacks clear justification and contradicts established principles.
  • The slogan 'homology equals synapomorphy' is presented as a flawed premise leading to wasted scientific discourse.

Conclusions:

  • Maintaining Hennig's view on homology, which includes symplesiomorphies, resolves logical inconsistencies.
  • Discarding the equivalence of homology and synapomorphy is recommended for accurate phylogenetic analysis.
  • The study advocates for a return to a more consistent and historically grounded definition of homology.