Zoönomia

Zoonomia, vol. I, or, the Organic Laws of Life was a work on biology by Erasmus Darwin, incorporating some early ideas of the theory of evolution more fully developed by his grandson Charles Darwin.

Relevant quotes

When we revolve in our minds the metamorphoses of animals, as from the tadpole to the frog; secondly, the changes produced by artificial cultivation, as in the breeds of horses, dogs and sheep; thirdly, the changes produced by conditions of climate and season, as in the sheep of warm climates being covered with hair instead of wool, and the hares and partridges of northern climates becoming white in winter; when, further, we observe the changes of structure produced by habit, as shewn especially by men of different occupations; or the changes produced by artificial mutilation and prenatal influences, as in the crossing of species and production of monsters: fourth, when we observe the essential unity of plan in all warmblooded animals, we are led to conclude that they have been alike produced from a single living filament.

— cited by the 1911 Encyclopedia Britannica, article Variation and selection