Charles Darwin

Boards HMS Beagle as an unpaid gentleman naturalist. He is 22, fresh out of Cambridge, where he studied divinity. The voyage is supposed to last two years. It lasts five.

The Beagle reaches the Galapagos Islands. Darwin collects finches, mockingbirds, tortoises, and iguanas. He doesn't realize what he has until he gets home and ornithologist John Gould identifies the finches as separate species, island by island.

Opens a notebook labeled "B" and sketches a branching tree of life. Writes "I think" at the top. It's the first diagram of evolution by common descent. He tells almost no one for twenty years.

Marries his first cousin, Emma Wedgwood. They will have ten children together. Three die in childhood. He worries constantly that inbreeding contributed to their illnesses. The man who will explain natural selection cannot stop wondering if his own family is evidence.

His daughter Annie dies at ten after months of illness. Darwin is destroyed. He writes a memorial calling her 'the joy of the household.' Some biographers say Annie's death kills his remaining faith in God.

Receives a letter from Alfred Russel Wallace describing a theory of natural selection nearly identical to his own. Twenty years of careful secrecy, and someone else arrives at the same idea independently. Friends arrange a joint presentation to the Linnean Society. Almost no one notices.

On the Origin of Species is published. 1,250 copies in the first print run. All sell on the first day. The book avoids the word "evolution" and mentions humans only once, in the final pages: "Light will be thrown on the origin of man and his history."

Publishes The Descent of Man. This time he says it directly: humans evolved from primates. He also introduces the theory of sexual selection. The public reaction is as furious as he'd feared for three decades.

Dies at Down House, Kent, at 73. His family plans a local burial, but a campaign by his colleagues secures a state funeral. He is buried in Westminster Abbey, a few feet from Isaac Newton.

The Scopes Trial. A Tennessee teacher is prosecuted for teaching Darwin's theory of evolution in a public school. Forty-three years after Darwin's death, his ideas are still on trial.