The great debate over evolution caught fire after Charles Darwin published his “On the Origin of Species” in 1859, but the question had been smoldering for years. The subject had first been written about 2,300 years earlier. In the ancient world philosophers were the scientist of their time; the question of how different animals and plants came to be and their relationships to each other were addressed by several thinkers.
Greek philosophers Anaximander and Xenophanes each studied fossils and individually came to the conclusion that life started in the sea and moved to land. Their theories on the evolution of life were rather strange, in one case believing that the earth climate was previously uninhabitable by humans, who in time emerged from the mouths of fish or fishlike animals. Although neither man had a theory of natural selection, their theories of life coming from the sea and their attempts to explain the world through observation with out relying on religion or mythology made them pioneers in scientific thought.
During the early modern era (1500-1800), several men toyed with the idea of evolution while adding to the world knowledge of animals and plants, how they are related, and developing a logical method of categorizing them. John Ray catalogued and described 18,600 plants. His definition of what constituted a species was based upon a common descent but didn’t extend his ideas to include evolution of species.
Carolus Linnaeus believed that new species could result from hybridization but that it was all guided by the hand of God. Linnaeus devised the method of classifying all organisms into the species, genus, family, order, phylum and kingdom that is still used today. By including man into his classification system he invited outrage by those that felt this was degrading to mankind.
Comte de Buffon and Pierre-Louis Moreau de Maupertuis each had a limited view of evolution. Buffon believed that God arranged the animal kingdom in a hierarchy and that after the fact evolution did take place due to environmental factors. Maupertuis came closer to the modern idea of evolution; he believed that speciation was caused by chance events in nature and introduced the idea of survival of the fittest. However, Maupertuis failed to elaborate on his ideas or adequately explain his conclusions.
These early pioneers in biology were hampered by the perceived age of the earth. This problem still plagues modern evolution scientists because although the accepted age of the earth has often been revised the time believed to be needed for evolution to take place continues to increase as well.
The age of the Earth was a subject of great speculation during the early modern period. According to James Ussher, a 17th century Anglican archbishop the world began in the year 4004 B.C. on October 23rd. Ussher used the Biblical accounting of generations as well as other recorded historical events to arrive at that date and time. Dr. Charles Lightfoot of Cambridge pinpointed creation more closely by adding that it all started at 9:00 AM of that date.
While the general public continued to assume that all of creation started approximately 6,000 years earlier the scientific world began to have doubts. In the mid 1700’s, the earlier mentioned Comte de Buffon begun to speculate that humans and apes were related but did so quietly and only those interested enough in the subject to read his limited edition forty-four volume set on natural history knew about it. He also kept his speculation that the world was created no less then 75,000 years ago.
Erasmus Darwin, the grandfather of Charles Darwin, was a country physician who dabbled in science and believed after reading all the scientific papers of the day that evolutions had occurred in humans as well as other life forms. The older Darwin’s ideas on how evolution worked were vague and poorly communicated in his written work. He also had come to believe the Earth was older then previously thought; life started, according to him, “millions of ages before the commencement of the history of mankind.”
By today’s theory of evolution, Erasmus Darwin was mostly correct in his ideas. He thought all life had a common ancestor and that the descendants branched out over time to evolve into all species. He concluded that species changed due to competition and sexual selection. What this Darwin lacked was what every scientist needs to go with his theory, evidence. Without evidence to support it, a theory is no better then speculation.
The year Charles Darwin was born was the year Jean-Baptiste Lamarck and while stating in his book “Philosophie Zoologique” that animals evolved from simpler forms, he went on to postulate some bizarre theories of evolution. For instance. Lamarck believe that if an animal overused a part of its body, the animal’s body would adapt by making its body part fit more closely its needs. His example was the giraffe, which he believed had such a long neck due to an ancestor stretching his neck to the point of making it longer. He further believed that the long neck was then conveniently passing down through the generations. His theories were so easily dismissed as to be laughable
Lamarck’s theory of how evolution worked was referred to as “fixity” of species whereas his contemporaries ascribed to the theory of catastrophism which was the belief that sudden natural catastrophes had killed off large populations who were then replaced with other species. Catastrophism was considered an explanation for the abrupt changes seen in fossil records.
Finally, Charles Darwin came along, and after examining the theories of those that came before him and gathering evidence to support a theory, modern evolutionary science was born.