Based on work conducted during his voyages aboard HMS Beagle, in addition to further scientific research and experiments in the subsequent two decades, the book presented evidence for the process of natural selection and sparked a seismic shift in the study of science. Although Darwin was not the first to propose evolution, his book was the first to present the idea outside the closed scientific community and its close ties to the Church of England. The idea of a fixed species had become a central part of scientific thought as a result of the Protestant Reformation, in which a literal interpretation of the Bible meant that the Genesis creation narrative was an exact historical account. These ideas began to be challenged from the middle of the 18th Century, with Darwin’s own grandfather Erasmus Darwin proposing a hypothesis on the transmutation of species in the 1790s in which slight genetic mutations are passed on to subsequent generations. His grandson’s work led him to infer that although populations have the potential for infinite growth, this is avoided due to limitations in the availability of the basic requirements for survival such as food, water and shelter and so only the fittest survive. Although the book barely hinted at the issue of human evolution it was, and continues to be, controversial. Despite this, Darwin’s theory of evolution by natural selection now forms the core of modern life sciences.