He suggested that climatic changes after the Ice Age resulted in a drying  of the climate, forcing people, plants, and animals into ever smaller regions; this resulted in closer contact between them and to the exploitation of the others by man.
The problem of how domestication arose was addressed in the 1930's by archaeologist Gordon Childe. He suggested that climatic changes after the Ice Age resulted in a drying  of the climate, forcing people, plants, and animals into ever smaller regions; this resulted in closer contact between them and to the exploitation of the others by man. FTP, name  this early theory, now generally rejected, variously named after either the small regions, the climate change, or the close contact.
The problem of how domestication arose was addressed in the 1930's by archaeologist Gordon Childe.
Oasis theory or Propinquity theory or Desiccation theory