200 Years. 200 Stories. Story
38: “Evolution in the Air
Title page for Leidy's Flora and Fauna within Living Animals
Evolution in the Air
Several historians have used the phrase “evolution was in the air” to describe the sentiment common among many naturalists and scientists during the first half of the 19th century. Evidence of the diversity of life in the tropics, the anatomical similarities among different groups of animals, and the succession of fossil forms over time challenged the idea of creation. Notable Europeans, including Jean-Baptiste Lamarck and Étienne Geoffroy Saint-Hilaire, proposed a variety of theories for evolutionary change or transmutation (the altering of one species into another).
In the United States, Academy naturalist Joseph Leidy discussed transmutation in the introduction to his 1853 monograph Flora and Fauna within Living Animals. He explained that “there appear to be but trifling steps from the oscillating particle of inorganic matter, to a Bacterium; from this to a Vibrio, thence to a Monas, and so gradually up to the highest orders of life!” His ideas were unpopular among some of his colleagues, yet six years later, widespread debate on the subject exploded with Charles Darwin’s On the Origin of Species.