Dog from multiple grey wolf populations, with the dingo and New Guinea singing dog "breeds" having developed at a time when human populations were more isolated from each other. In the third edition of "Mammal Species of the World" published in 2005, the mammalogist listed under the wolf "Canis lupus" its wild subspecies, and proposed two additional subspecies: ""familiaris" Linneaus, 1758 [domestic dog]" and ""dingo" Meyer, 1793 [domestic dog]". Wozencraft included "hallstromi" - the New Guinea singing dog - as a taxonomic synonym for the dingo. Wozencraft referred to the mDNA study as one of the guides in forming his decision.
Species problem for some biologists over the objectivity of species, and some came to wonder whether individual species could be objectively real — i.e. have an existence that is independent of the human observer. In the 1920s and 1930s, Mendel's theory of inheritance and Darwin's theory of evolution by natural selection were joined in what was called the modern synthesis. This conjunction of theories also had a large impact on how biologists think about species. Edward Poulton anticipated many ideas on species that today are well accepted, and that were later more fully developed by Theodosius Dobzhansky and Ernst Mayr, two of