Darwin as a botanist

Charles Darwin on his voyage aboard H. M. S. Beagle contracted a mysterious illness that persisted throughout his life. Despite being ill, he continued his writings. He is remembered as the scientist who putforth the theory that species are changing. A species evolves by the accumulation and preservation of successive slight favourable variations, now known as mutations. In his quest to strengthen his theory on the common origin of all life, and evolution by natural selection, he increasingly turned to plants and carried out experiments at his home-cum-laboratory, focusing on phenomena commonly associated with animals namely, movement. In plant roots, seedlings and climbing plants, he described nyctitropism, geotropism, phototropism and circumnutation. Darwin described the sleep movements in plants in which the petiole hangs down and the leaflets press together in the evening.