I summon the supernatural beings
Who first contrived
The transmorgifications
In the stuff of life.
You did it for your own amusement.
Descend again, be pleased to reanimate
This revival of those marvels.
Reveal, now, exactly
How they were performed
From the beginning
Up to this moment.
                                        Ovid: Metamorphoses (trans. Ted Hughes)

Biology in the 18th century
     The Classical Tradition: Plato & Aristotle (4th cent. BCE)
       Theory of Forms (essences, eidos)
                  'real' objects manifestations of 'ideal' forms
                  variation illusory  [see Plato, Book VII of "The Republic"]
       Dichotomy: world composed of paired opposites
                  "A" versus "not A" classes
                  good / bad, right / wrong, up / down, light / dark, male / female, etc.
           e.g., vertebrates vs. invertebrates
       Aristotle - "Father of Biology"
                Five books on zoology ("Generation of Animals")
                Biological structures have purpose: Efficient versus Final Causes

     Natural Theology: "The Wisdom of God, Manifested in His Creation"
            'Ideal' forms exist in Mind of God:
                  'real' world created by God (Genesis 1:1)
       Scala Naturae: the "Great Chain of Being"
                  Creation infinitely graduated progressive series
                  Time scale short (ca. 6,000 years)
                  Species static: no new forms, no change, no extinction
            Study of nature a pious activity

     Linnaen Taxonomy (Carl von Linne [Carolus Linnæus]
          "Systema Naturae" (1735; 10th ed. 1758)
                  4,162 animals described in KCOGS system [P & F added later]
           binomial nomenclature: genus + species names
                  "ad majorem Dei gloriam": for the greater glory of God

     Exploration creates a Scientific Crisis
       New forms discovered that don't fit Scala
       Extinctions evidently occur
       Variation real in space: what about in time?

Biology in the early 19th century:
      Change has occurred, how to explain it?
     The Enlightenment favors rational explanation.

     Jean Baptiste de Lamarck: "Zoological Philosophy" (1809)
            Formulated theory of Progressive Evolution to explain Scala [S&R 1.1]
            New features arise from persistent "besoin" (need / want)
                  (teleological: goal-directed explanation)
            Use & disuse alter morphology
            Altered morphology passed on to offspring
                  (Lamarckism: inheritance of acquired characteristics)
             Ex.: Giraffes stretch necks to feed on higher leaves.
                           Successive generations gradually acquire longer necks.
                           Therefore, organisms change (evolve) over time

     Uniformitarianism replaces Catastrophism in geology
       Charles Lyell: "Principles of Geology" (1830)
       Observable, gradual processes + enormous time = world geology