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Charles Darwin
He established that all species of life have descended over time from common ancestors, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. -
Charles Darwin, in "The Origin of Species," and Alfred Russell Wallace,
Charles Darwin, in "The Origin of Species," and Alfred Russell Wallace, both propose theories of evolution through natural selection. Organisms that are better suited to the environment are more likely to survive and reproduce, forcing species to change, or evolve. -
Francis Crick and James Watson
Francis Crick and James Watson discover the double-helix structure of DNA, unlocking heredity's "memory storage" mechanism.