In the early 1800s, Christianity taught that God created every species to be perfectly adapted to its environment. The Book of Genesis also taught that humans were made in God's image, different form all other animals and ruling over them. In contrast, some scientists argued that species evolved gradually over time. There were many different theories of how this occurred. Darwin put forward his theory in 'On the Origin of Species', publishes in 1859. Darwin's book claimed that all creatures evolved from common ancestors through a process called natural selection. In a later book, he wrote about about humans, arguing that they shared a common ancestor with apes. Darwin's writings went against the Christian idea Chatman's nature was different form other animals.