1) Struggle for existence

2) Variation in fitness (how well one survives and reproduces)

3) Inheritance of Variation (what ever the cause of survival and reproduction is to be passed on to the next generation)

• Thomas Malthus: read his essay on the principle of population and how population increases exponentially over time, and he though that doesn't this apply to animals as well? Animals more then just double so there must be a struggle for existence.
• Charles Lyell: read essay on principles of geology that said the earth has been around for billions of years *uniformatarianism: work towards living world as well.
• His grandfather: was very radical and believed in evolution his name was Erasmus and he was a naturalist as well the boys looked up to him.
• Alfred Russell Wallace another naturalist camp up with same theories of "orgin of speices" natural selection
• Carl Linnaeuos: current ideas about the  natural world that darwins ideas ran counter to