Yeasts do not form a single taxonomic or phylogenetic grouping. It should be noted here that the phylogenetic classification of fungi is designed to group fungi on the basis of their ancestral relationships, also known as their phylogeny. The genes possessed by organisms in the present day have come to them through the lineage of their ancestors. A phylogenetic tree, also known as phylogeny, is a diagram that depicts the lines of evolutionary descent of different species, organisms, or genes from a common ancestor. As the diagram suggests, Yeasts are a polyphyletic group of many single-celled organisms that evolved from the common ancestor of all fungi.