History of Evolutionary Thought
Many people throughout centuries and in many different countries contributed to the modern conception of evolution and its mechanisms, this is a brief overview:
Ancient Greeks saw commonalities throughout living things which led to the idea of "The Great Chain of Being" which describes life as an ascension from least "godly" to most "godly". This thought was derived from the concept of Essentialism, which explained differences of form as a result of differences in the amount of four "humors" (black bile, yellow bile, blood, and phlegm) which an organism contained. Aristotle, however proposed fixity of species by organizing life into a sort of ladder. Each rung had creatures assigned to it, but it was immutable (no ascension). Aristotle's theories were the accepted truth for many years especially due to the fact that they correlate with the Bible's teachings.
-Erasmus Darwin(1731-1802): Formulated one of the first official theories of evolution in his books: Zoonomia, or the Laws of Organic Life.
-Jean Baptiste de Lamarck (1744-1829): Species evolve, Inheritance of Acquired Characteristics, organisms are striving for perfection.
-Rev. Thomas Malthus (1766-1834): Wrote an Essay on the Principle of Population, which generally gives the model that populations will grow exponentially until resources are depleted. This essay inspired Darwin as quoted from his autobiography (1876):
"In October 1838, that is, fifteen months after I had begun my systematic inquiry, I happened to read for amusement Malthus on Population, and being well prepared to appreciate the struggle for existence which everywhere goes on from long- continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The results of this would be the formation of a new species. Here, then I had at last got a theory by which to work".
-Lyell (1797-1875)- Considered to be the father of modern biology. His observations lead to the theory of Gradualism in which uniform changes in earth's composition (erosions, earthquakes etc.) lead to large scale changes of terrain which would mean that the earth could be much older than the 6,000 years which is predicted by The Bible. These observations influenced Darwin by shedding new light on the age of the earth, which would make it possible for evolution to have occurred.
-Alfred Russel Wallace (1823-1913): Darwin and Wallace's theories are parallel in that they are essentially identical, and were created at the same time. Wallace however, was studying in Malaysia while Darwin was studying in the Galapagos. Darwin is usually given credit for the theory of Natural Selection due to the fact that he wrote the comprehensive book: The Origin of the Species.
-Charles Darwin(1809-1882): Throughout his journey on the H.M.S. Beagle, he observed phenomena which cemented in his mind the idea that species did in fact evolve. This was not a new idea to Charles Darwin as his grandfather Erasmus had been a proponent of the theory. Darwin is accredited with deriving the mechanism by which this occurs: Natural Selection. His book: On the Origin of Species by Means of Natural Selection or Preservation of Favored Races in the Struggle for Life was written in 1859 and contained huge amounts of evidence in favor of the theory. Darwin is given so much credit in the theory despite the enormous amount of people who contributed to the theory due to the fact that he was able to take evidence compiled by Malthus, Lyell etc. etc., add it to what he witnessed in nature and from this vast amount of information synthesize his theory.
Principle ideas from The Origin: Perpetual change, common decent, diversification, gradualism
For a more complete history: Timeline of Evolutionary Thought
This page was made for Honors 210, a course offered at Monmouth College