Robert Chambers (1802-1871)
Robert Chambers was a Scottish bookseller, journalist, geologist, who owned the firm W. & R. Chambers Publishers, a well known publishing company that still exists today. He was a very prominent figure in the upper and middle classes of the time, and aware that by the mid-nineteenth century, the classical view of human history with a divine origin was beginning to fall apart. The notion of slow changes producing evolution had started to permeate into the atmosphere. In 1844, Chambers authored an anonymous publication titled Vestiges of the Natural History of Creation. His intention was to answer big questions. How and when did the Earth begin? How has it changed? How did life start?
The book was widely criticized for suggesting that the planet had started from a cloud of gas, that life had emerged spontaneously, and fossils had transmuted from aquatic creatures to reptiles to birds, producing apes and then humans. It was until after Chambers death that his authorship was confirmed. Though the book was very controversial, his proposal lacked the explanation of the mechanism that would account for the changes that he described.
Thomas Henry Huxley (1825-1895)
Huxley was a self-taught English biologist, best known as Darwin’s Bulldog, because even when he was not fully convinced of the gradualism of evolution, in public he always was on Darwin´s side, no matter what. He was among the first to learn about Darwin’s theory, even before it was published. Huxley’s famous reaction to the idea of natural selection was to say: ” How extremely stupid not to have thought of that! He is well-known for coining the term agnostic, having been the first one to say that birds descended from dinosaurs, and for defending Darwin in his famous debate with Samuel Wilberforce, the Bishop of Oxford. Wilberforce attacked Huxley asking him to say whether he descended from an ape on his mother’s side or his father’s side.
The story goes that Huxley replied something like “I’d rather descend from an ape than from a man magnificently endowed by nature and influential, who uses his gifts to ridicule scientific discussion and to discredit those who humbly seek the truth.”
Thomas Malthus (1766 – 1834)
Malthus was an English clergyman and economist who published his theory in 1798 under the title An Essay on the Principle of Population. Malthus argued that human populations grow geometrically while food supply grows arithmetically. Geometric growth means that the increase is proportional to the function’s current value. An example of geometric growth is the series 2, 4, 8, 16, 32, 64, 128, etc. Arithmetic growth means the increase is by a fixed amount. An example of arithmetic growth is the series 2, 4, 6, 8, 10, 12, 14, etc. Since the population grows much faster than the food, there comes a time when the population exceeds the resources. Darwin read Malthus and generalized the theory to all species. He realized that even species that reproduce slowly, like elephants, can exceed their resources given enough time.
So there must be some competition between individuals who fight for limited resources. Since they are insufficient, there must be a struggle for survival. Furthermore, Darwin knew there is variability among individuals in any species. He concluded that there should be some traits characterizing the better-adapted individuals. Those who are the fittest reach reproductive age and leave offspring who inherit their traits. The unfit die before reproducing, leave no offspring, and their features disappear. That was exactly the way how populations were evolving over time.