Leghorn, Brahma, Plymouth Rock, Sussex, Australorp are all different breeds of poultry which are developed through

Man has domesticated many animals and crops. This intensive breeding programme has created breeds that differ from other breeds (e.g., dogs, poultry, etc.) but still are of the same group. This is artificial selection.

Compared with natural selection, the process of artificial selection is motivated by human needs and acts more rapidly with more visible results over a short time period. This process has been further accelerated following the development of current breeding programs and the emergence of specialised breeding companies.