Taxonomy is a branch of the biological sciences. It is the classification of all living organisms. This helps scientists define which species are more related and how their evolutionary line may appear. Organisms are grouped together into taxa (singular taxon) and given a taxonomic rank. The Swedish botanist Carolus Linnaeus is regarded as the father of modern taxonomy, as he developed a system known as Linnaean classification for categorization of organisms and binomial nomenclature for naming organisms. Before Linnaeus, organisms were grouped with other organisms with similar looks and behaviour. For example birds and bats would have been grouped together and whales and fishes may have been grouped together.