Alfred Russel Wallace is finally heading back to England after four arduous years of collecting animals in the Amazon jungle
Wallace's specimens and records are destroyed when the ship catches fire
Wallace vows that if he survives, he will never sail again
Charles Darwin set sail on his own voyage 20 years before Wallace's shipwreck
Darwin was an unlikely revolutionary, as most scientists at the time believed that each species was specially created by God
Darwin was a passionate amateur naturalist who got the chance to see and collect animals, plants, and rocks around the globe on the Beagle voyage
Darwin was often seasick and suffered greatly during the voyage
Darwin found fossils of extinct creatures that were much larger than living species
When Darwin arrived in the Galapagos, he was more exhausted than excited
Darwin noticed that the tortoises and mockingbirds on different Galapagos islands looked quite different from each other
Darwin started to consider the possibility that species might change over time, rather than being specially created
Darwin's ideas were revolutionary and ran against church teachings and what most Europeans believed
Darwin was still keeping his biggest idea secret, even as he became England's most prominent naturalist
Wallace had survived his ordeal at sea after his ship caught fire
Wallace and Darwin met for the first time, with Wallace being an earnest young man and Darwin being in a more established position
Wallace was open about his interest in the origin of species, while Darwin was secretive about it
Wallace was about to head to the Malay Archipelago to do research, and offered to send specimens back to Darwin
Wallace and Darwin are meeting for the first time. The two explorers share a great passion for nature, but they are in very different situations.
Wallace is single. He has to collect for a living, and he has yet to make his mark.
Darwin is married and has a family. He is financially well-off and has a scientific reputation to protect.
Wallace is as open as Darwin is secretive about his interest in the origin of species. Little does Darwin know that this young man will soon force his hand.
And Wallace doesn't have a clue that Darwin has already scooped him.
Believing that the question of the origin of species is still wide open, and despite having nearly lost his life at sea, Wallace sets out on a new voyage.
He travels to the region between the Pacific and Indian oceans, the Malay Archipelago. For the next eight years he will collect and study animals, as he hops from island to island in a 14,000 mile journey.
Wallace is captivated by butterflies. His favorite group is called birdwings after their shape and large size. They command a high price for their striking colors.
He finds birdwing butterflies throughout the archipelago. He identifies new species, some that are slightly different from those on nearby islands.
The Malay butterflies suggest to Wallace what the Galapagos animals revealed to Darwin-- species change.
But Wallace, too, seeks to understand the bigger picture. Having explored jungles on opposite sides of the globe, he can compare where different groups of animals live, and ask why they are found where they are.
Wallace the collector now becomes Wallace the theorist.
Birdwings occur near other species of bird wings in the Malay Archipelago. Across the globe in the Amazon lived different families of butterflies. Bird families also clustered geographically.
Cockatoos live only in the Malay Archipelago and Australia, whereas the Americas are home to macaws and hummingbirds.
Around the globe, the more similar two species are, the closer they tend to live.
Wallace's law of nature
Species don't appear in random places. They arise near similar species.
Wallace realizes the profound implication that species are connected to one another, like the branches of a tree.
Wallace finds more evidence that all species are related by considering some intriguing creatures. Manatees are mammals that live entirely in the sea. But inside their flippers are finger bones. Similar apparently useless bones are inside whale flippers, too.
Imperfections such as these vestigial structures make it clear that every species is a modified form of an older species.
Zig-zagging across the Malay Archipelago, Wallace gathers critical evidence for his law.
On the island of Borneo, he sees monkeys and orangutans. But elsewhere in the archipelago, in New Guinea, the mammals are strikingly different. No monkeys here-- instead, up in the branches are tree kangaroos, marsupials whose young grow up in pouches.
Island by island, Wallace notes which of the two groups of mammals lives there-- those with pouches and those without. Animals on the eastern islands resemble those of Australia, animals to the west, those of Asia. It as if a line splits the archipelago. It will be dubbed the Wallace Line.
Why would God draw a boundary through these islands and put monkeys in the trees on one side and put kangaroos in the trees on the other side? This made no sense. Special creation couldn't explain the line, but Wallace's earlier law could, that species come from pre-existing nearby species.