Call Us: US - +1 845 478 5244 | UK - +44 20 7193 7850 | AUS - +61 2 8005 4826

Growth of Biological Thought: Diversity, Evolution, and Inheritance

With Darwin’s theory, a general acceptance quickly appeared that a classification should reflect the Darwinian principle of common descent.[41] Tree of life representations became popular in scientific works, with known fossil groups incorporated. One of the first modern groups tied to fossil ancestors was birds.[42] Using the then newly discovered fossils of Archaeopteryxand HesperornisThomas Henry Huxley pronounced that they had evolved from dinosaurs, a group formally named by Richard Owen in 1842.[43][44] The resulting description, that of dinosaurs “giving rise to” or being “the ancestors of” birds, is the essential hallmark of evolutionary taxonomic thinking. As more and more fossil groups were found and recognized in the late 19th and early 20th centuries, palaeontologists worked to understand the history of animals through the ages by linking together known groups.[45] With the modern evolutionary synthesis of the early 1940s, an essentially modern understanding of the evolution of the major groups was in place. As evolutionary taxonomy is based on Linnaean taxonomic ranks, the two terms are largely interchangeable in modern use.[citation needed][46]

The cladistic method has emerged since the 1960s.[41] In 1958, Julian Huxley used the term clade.[12] Later, in 1960, Cain and Harrison introduced the term cladistic.[12] The salient feature is arranging taxa in a hierarchical evolutionary tree, ignoring ranks.[41] A taxon is called monophyletic, if it includes all the descendants of an ancestral form.[47][48] Groups that have descendant groups removed from them (e.g. dinosaurs, with birds as offspring group) are termed paraphyletic,[47] while groups representing more than one branch from the tree of life are called polyphyletic