The variation of animals and plants under domestication Volume II presents an examination of how living organisms change when shaped by human influence, focusing on the forces that drive alteration across generations. The work begins by clarifying that the goal is not to list every domesticated form but to highlight evidence that reveals how selection, environment, and inherited differences interact to produce noticeable shifts in structure and behavior. Through examples drawn from familiar species, the discussion shows how accumulated variations can become pronounced under sustained human guidance, emphasizing the roles of controlled breeding, altered surroundings, and natural variability. The opening chapters introduce foundational ideas about inheritance and the plasticity of life, suggesting that even small changes can build into significant transformations over time. The study encourages readers to consider the dynamic relationship between humans and the organisms they cultivate, presenting domestication as a process that uncovers deeper principles about adaptability and the ongoing modification of nature.