I am a naturalist, geologist and biologist. My research showed that all species of life descend from a common ancestor, and with Alfred Russel Wallace I introduced natural selection as the process that drives that branching.
Critics said my theory failed because it did not explain the origin of life. I answered that science accepted Newton's law of gravity though the cause of gravity was unknown.
In The Descent of Man (1871) I applied evolution to human origins, society and mental abilities and developed sexual selection; in The Expression of the Emotions (1872) I traced human psychology back to animal behaviour.
In my 1861–62 orchid research I used natural selection to make a testable prediction: a Madagascar orchid with a sixteen-inch nectary implied an unseen moth with a proboscis long enough to drain it.
After Wallace's parallel work forced the issue, our theory was read at the Linnean Society on 1 July 1858. Thirteen months later I finished On the Origin of Species, whose 1,250 copies were oversubscribed on its first day of sale.
In November 1854 I realised why descendants of one species differ more and more: each becomes adapted to "diversified places in the economy of nature". This principle of divergence completed my theory.
From 1846 I dissected and classified the barnacles from my voyage, producing the definitive work on the group. Using my theory I found homologies and tiny parasitic males, and in 1853 the research won the Royal Society's Royal Medal.
On the Beagle I reasoned that as land rose elsewhere, oceanic islands sank and their fringing coral reefs grew upward into atolls. I published the theory in The Structure and Distribution of Coral Reefs in May 1842.
In 1838 I combined Malthus's principle of population with the struggle for existence in nature, then saw that nature selects among chance variants the way farmers select breeding stock. I named the mechanism natural selection.
I built my research data by questioning expert naturalists and, unconventionally, farmers and pigeon fanciers, then ran my own selective-breeding experiments and a worldwide correspondence network.
My plant and soil research ran alongside evolution: I was first to recognise the significance of carnivory in plants, traced the movements of climbing plants, and turned an 1837 idea about earthworms and soil into my final book.
In my 1837 B notebook I sketched descent as a single branching tree and wrote that "It is absurd to talk of one animal being higher than another", discarding Lamarck's ladder of progress.
From 1831 to 1836 I worked ashore while HMS Beagle charted the South American coast, investigating geology, collecting specimens and keeping careful notes. That fieldwork became the evidence base for all of my later science.
