Animal genetic resources for food and agriculture crop and livestock species in the early neolithic time period changed our human evolution and lifestyles. This ability to control food production led to major demographic, technological, political and military changes. Consecutively, thousands of years of natural and human selection, genetic drift, inbreeding, and crossbreeding have contributed to the diversification of animal genetic resources and increased the variety of environments and production systems that livestock keeping takes place. Relatively few species have been domesticated; out of the world's 148 non-carnivorous species weighing more than 45 kg, only 15 have been successfully domesticated. The proportion of domesticated birds used for food
Methods used to study memory use single cell recordings solely for experimental purposes is exclusive to animal testing and has greatly increased our understanding of memory systems. Comparisons of the neuroanatomy of caching and non-caching birds has shed light on the neural basis of spatial memory. David Sherry and his colleagues devised experiments using the displacement of landmarks, to show that caching birds rely on spatial memory and landmark cues to find their caches, and local changes in cache appearance had no effect on food retrieval. They were able to show that changes in neurogenesis are directly related to food storing behavior. Food caching behavior