Darwin’s ideas made a huge impact in literature. By the end of the nineteenth century, literary development was tending strongly toward realistic, even naturalistic works, which laid out a world devoid of overt morality, where primitive emotions, self-centered motives, and hereditary failings came to rule lives and societies. Darwinian evolution was of a piece with this, especially as some writers, such as Émile Zola in France, hoped to develop a scientific literature, that is, imaginative writing that so emulated reality that it could present life under the microscope. Also, naturalist writers like Jack London set his most famous novel in nature with "Call of the Wild" and "White Fang".
It also brought about political changes. Darwin had a significant influence on Karl Marx. Struggle and survival are central to Darwin's theory of evolution and Marx would be influenced by these thoughts to write the "Communist Manifesto". He used Darwin's theory in application to human class struggle.
