Although his duties on HMS Rattlesnake on a 4-year voyage around Australia were as surgeon and he had only a microscope and makeshift net as equipment for natural history, he did useful new work on plankton and after a discouraging interval this established him on the scientific scene in London. However, these interests exasperated the Admiralty and he became a self-employed writer on science in 1850 and a lecturer on natural history from 1854 at the School of Mines. This gave him an income to marry his Australian girlfriend of 8 years before; they eventually had seven children. Their son Leonard was the father of Julian (biologist), Aldous (writer) and Andrew Fielding Huxley (physiologist). For 30 years, while waiting for a job in physiology, Huxley worked in zoology and palaeontology.

These interests led him to his best-known place in science, that of advocate for his friend Darwin’s ideas on evolution; in famous debates and essays on this Huxley showed his forceful expertise. However, in a debate with Bishop Wilberforce at the British Association meeting in Oxford in 1860, his reply to the Bishop’s query on whether Huxley’s ancestry was from an ape on his grandfather’s or his grandmother’s side is variously reported and it is unclear who was the victor. He was a lucid and elegant writer and a charming man. His careful study of the primates established man as one of them and made evolution a matter of public debate in terms of science rather than emotion. Aside from all this, Huxley did much excellent work of his own in zoology and palaeontology and in shaping biological education. One of his students in the 1880s was H G Wells, who admired him enormously and whose early novels were much influenced by Huxley’s teaching.