The Variation of Animals and Plants Under Domestication, Volume II

Inherited traits and the choices of breeders give Charles Darwin a way to examine variation in domesticated animals and cultivated plants. The contents move through pedigrees, the return of ancestral traits, crossing, fertility and selection. Pigeons, cattle, fruit trees and flowering plants provide examples of characteristics that persist, disappear or change. Chapters on climate, food and habits extend the discussion beyond breeding to the conditions in which organisms live.

Darwin's treatment of environmental change shows how carefully he weighs competing explanations. He distinguishes direct effects on structure from useful variations accumulated through natural selection, and considers why similar conditions can lead to different results. The argument repeatedly returns to the constitution of the organism itself. For readers interested in the history of biology, this volume offers a detailed account of how observations of farm animals and garden plants enter broader debates about inheritance and adaptation.