As opposed to "fowl", "poultry", on the other hand, is a term for any kind of domesticated bird or bird captive-raised for meat or eggs; ostriches for example are sometimes kept as poultry, but are neither gamefowl nor waterfowl. In colloquial speech, the term "fowl" is however often used near-synonymously with "poultry" or even "bird", and many languages do not distinguish between "poultry" and "fowl". Nonetheless, the fact that Galliformes and Anseriformes most likely form a monophyletic group makes a distinction between "fowl" and "poultry" warranted.
Many birds that are eaten by humans are fowl, including poultry such as chickens or turkeys, game birds such as pheasants or partridges, other wildfowl like guineafowl or peafowl, and waterfowl such as ducks or geese.
While they are extremely diverse ecologically and consequently, in an adaptation to their different lifestyles, also morphologically and ethologically, there are still some features which unite water- and landfowl. Many of these, however, are plesiomorphic for Neornithes as a whole, and are also shared with paleognaths.
Fowl were the first neognath lineages to evolve. From the limited fossils that have to date been recovered, the conclusion that they were already widespread - indeed the predominant group of modern birds - by end of the Cretaceous is generally accepted nowadays. Fossils such as Vegavis indicate that essentially modern waterfowl - albeit belonging to a nowadays extinct lineage - were contemporaries of the (non-avian) dinosaurs. As opposed to the morphologically fairly conservative Galliformes, the Anseriformes have adapted to filter-feeding and are characterized by a large number of autapomorphies related to this lifestyle. The extremely advanced feeding systems of the Anseriformes, together with similarities of the early anseriform Presbyornis to shorebirds, had formerly prompted some scientists to ally Anseriformes with Charadriiformes instead (see also "Graculavidae"). However, as strong support for the Galloanserae has emerged in subsequent studies, the fowl clade continues to be accepted as a genuine evolutionary lineage by the vast majority of scientists.
Apart from the living members, the Gastornithiformes are probably a prehistoric member of the Galloanserae.
