An early thinker in what grew to become the study of evolution, Lucretius believed nature experiments endlessly across the aeons, and the organisms that adapt best to their environment have the best chance of surviving. Living organisms survived because of the commensurate relationship between their strength, speed, or intellect and the external dynamics of their environment. Prior to Charles Darwin's 1859 publication of On the Origin of Species, the natural philosophy of Lucretius typified one of the foremost non-teleological and mechanistic accounts of the creation and evolution of life. In contrast to modern thought on the subject, he did not believe that new species evolved from previously existing ones and denied that modern animals, which dwell on land, derived from marine ancestors. Lucretius challenged the assumption that humans are necessarily superior to animals, noting that mammalian mothers in the wild recognize and nurture their offspring as do human mothers.
