Evolutionary Thought

• Aristotle's Scala Naturae, or 'Ladder of Life', shows how all living things are connected, with humans at the top and inanimate matter at the bottom

  
• The Scala Paradisi (Ladder of Paradise) by Albrecht Dürer in 1529 illustrates the ascent of the soul to heaven, based on St. Bernard of Clairvaux's writings

  
• Charles Darwin and Alfred Russel Wallace independently developed the concept of evolution based on observations on flora and fauna

  
• A quote from Charles Darwin

  
• Evolutionary Thought:

  • The study of changes undergone by species over time and the processes involved
  • Started in antiquity and continues to modern times
• Greek Philosophers:

  • Anaximander proposed animals, including humans, may have originated from an aquatic animal
  • Empedocles suggested present-day animals and plants were combinations of early ones
• Plato and Essentialism:

  • Organisms did not change over time
  • All organisms are already perfect
  • All organisms exist simultaneously
• Aristotle and Scala Naturae:

  • Described in Historia animalium
  • Proposed the Great Chain of Being, with more complex organisms higher in the hierarchy, humans being the highest form
• Tao: Eastern Evolutionary Thought sees humans, nature, and the universe as ever-changing and in constant transformation
• The Romans:

  • Lucretius described natural mechanisms for changes in living things
  • Origen and Augustine argued that the story of creation in Genesis should not be taken literally
• Christian Philosophy and Evolutionary Thought:

  • Rediscovery of Plato and Aristotle's works led to the re-emergence of the perfect being concept and scala naturae
  • Species were considered not to change
• The Scientific Revolution:

  • Notable scientists like Descartes and Maupertuis stated natural events occurred without divine intervention
  • Leclerc and Burnett proposed species arose from a common ancestor
  • Diderot introduced the idea of natural selection
• The Early 19th Century:

  • Paleontology, geology, and anatomy developments supported the idea of organisms changing over time
  • Mechanisms of evolutionary change were debated, focusing on divine intervention or intelligent design
• Transmutation of Species by Lamarck:

  • Organisms do not have a common ancestor
  • Belief in spontaneous generation
  • Innate life force drives evolution
  • Idea of use and disuse
• Natural Selection by Darwin and Wallace:

  • Independently developed the concept of evolution based on observations
  • Darwin's "The Origins of Species by Natural Selection" (1859) and Wallace's "Contributions to the Theory of Natural Selection" (1870)
• The Church's stance on evolution:

  • Roman Catholic Church recognizes Darwinian evolution
  • Rejects Intelligent Design and Young Earth Creationism
  • Supports theistic evolution
• Proposed drivers of evolution:

  • Theistic evolution
  • Neo-Lamarckism
  • Orthogenesis
  • Saltationism
• Mendelian Genetics and Evolution:

  • Mendel's work explained how variation occurs and genes are transferred
  • Mutation alone is not enough for a new species
• The Modern Synthesis:

  • Combination of Mendel's Law of Inheritance with Darwin's Theory of Natural Selection
  • Genetic variation acted upon by natural selection explains evolution