Between 1860 and 1868, the life and work of Charles Darwin from Orchids to Variation continued with research and experimentation on evolution, carrying out tedious work to provide evidence of the extent of natural variation enabling artificial selection. He was repeatedly held up by his illness, and continued to find relaxation and interest in the study of plants. His studies of insect pollination led to publication of his book Fertilisation of Orchids as his first detailed demonstration of the power of natural selection, explaining the complex ecological relationships and making testable predictions. As his health declined, he lay on his sickbed in a room filled with inventive experiments to trace the movements of climbing plants.

Darwinism became a movement covering a wide range of evolutionary ideas. In 1863 Lyell's Geological Evidences of the Antiquity of Man popularised prehistory, though his caution on evolution disappointed Darwin. Weeks later Huxley's Evidence as to Man's Place in Nature showed that anatomically, humans are apes, then The Naturalist on the River Amazons by Henry Walter Bates provided empirical evidence of natural selection. Lobbying brought Darwin Britain's highest scientific honour, the Royal Society's Copley Medal, awarded on 3 November 1864. That day, Huxley held the first meeting of what became the influential X Club devoted to "science, pure and free, untrammelled by religious dogmas".

Admiring visitors included Ernst Haeckel, a zealous follower of "Darwinismus" in a translation favouring progressive evolution over natural selection. Wallace remained supportive, though he increasingly turned to Spiritualism.

The first part of Darwin's planned "big book", The Variation of Animals and Plants Under Domestication, grew to two huge volumes, forcing him to leave out human evolution and sexual selection. It sold briskly in 1868 despite its size, and was translated into many languages. Darwin's work on the Descent of Man and Emotions followed after this publication.