When Darwin left England in 1831 he accepted the religious dogma of special creation. Malthus maintained that human population increases geometrically yet the means of sustenance increase arithmetically. He claimed that sometime in the future human population growth would exceed resources and there would be intense competition causing war, misery and famine. Darwin realized that perpetual selection existed in nature in the form of natural selection . In contrast to artificial selection, the breeder is replaced by conditions in the environment that prevent the survival and reproduction of certain individuals.
Natural selection occurs without a conscious plan or purpose.
In 1858, while Darwin was working on his manuscript outlining his theory of evolution, he received a manuscript for review by a young English naturalist named Wallace . Wallace was a naturalist working mostly in the Malay Archipelago. He had also read Essay on the principle of population by Malthus and it came into his mind during a malarial fever. G. Darwin wanted to let Wallace publish first but Lyell convinced him that they should jointly present their work. Papers by both Darwin and Wallace were read before the Linnaean Society of London on July 1, 1858.