Phylogenetic Species Concept

Phylogenetic Species Concept
Peter Halasz. (User:Pengo) · Public domain · source
Name	Phylogenetic Species Concept
Taxon	Species concept
Author	Multiple

Phylogenetic Species Concept

The Phylogenetic Species Concept defines species based on diagnosable monophyletic groups identified by shared derived characters, rooting taxonomy in evolutionary history. It emphasizes lineage divergence and unique character states as the basis for delimitation, integrating methods from systematics, molecular biology, and paleontology. The concept has influenced modern revisions across botany, zoology, microbiology, and conservation policy.

Definition and criteria

Under the Phylogenetic Species Concept a species is typically diagnosed as the smallest monophyletic group of organisms that share one or more unique, derived character states, often called synapomorphies. Authors and institutions that promoted this framing include Willis J. G. D., Joel Cracraft, Ernst Mayr (as a point of contrast), George Gaylord Simpson (contextual influence), and organizations such as the American Museum of Natural History, Smithsonian Institution, and Royal Botanic Gardens, Kew. Criteria commonly cited encompass monophyly on a genealogical tree; diagnosability via fixed character differences; and lineage-based distinctness as used by agencies like the International Union for Conservation of Nature and herbaria such as the Royal Botanic Garden Edinburgh.

Historical development and proponents

The concept evolved from earlier work in phylogenetics and systematics by figures associated with institutions like the Field Museum of Natural History, Natural History Museum, London, and academic centers including Harvard University and the University of Chicago. Key proponents included Joel Cracraft and colleagues who synthesized cladistic principles at meetings such as the International Congress of Systematic and Evolutionary Biology and in journals tied to the Linnean Society of London. Debates engaged contrasting positions from evolutionary biologists linked to Ernst Mayr at institutions like the American Museum of Natural History and paleontologists influenced by George Gaylord Simpson at the Museum of Comparative Zoology.

Methods and evidence used

Practitioners employ morphological, molecular, cytogenetic, and fossil evidence to infer monophyly, drawing on laboratories and collections at institutions such as Cold Spring Harbor Laboratory, Sanger Institute, Max Planck Institute for Evolutionary Anthropology, and museums including the Smithsonian Institution National Museum of Natural History. Molecular methods include DNA sequencing from facilities like the European Molecular Biology Laboratory and phylogenetic inference using software developed in academic settings like University of California, Berkeley and University of Oxford. Paleontological context often leverages stratigraphic frameworks established by researchers at the Natural History Museum, London and the American Museum of Natural History to place extinct taxa. Statistical support for clades is commonly assessed using algorithms and approaches originating from universities such as Princeton University, University of Michigan, and Stanford University.

Comparison with other species concepts

Compared to the Biological Species Concept advocated by Ernst Mayr and institutions like Cold Spring Harbor Laboratory, which emphasizes reproductive isolation, the Phylogenetic Species Concept prioritizes diagnosable monophyly as advanced in forums including the Society for the Study of Evolution. The Morphological Species Concept used in classical taxonomy at places like the Natural History Museum, London relies on phenotypic similarity, while the Ecological Species Concept discussed at meetings of the Ecological Society of America emphasizes niche differentiation. Debates have played out in journals associated with the Linnean Society of London, American Society of Mammalogists, and the International Union for Conservation of Nature.

Applications in taxonomy and conservation

The Phylogenetic Species Concept has been applied in taxonomic revisions in floras and faunas curated by the Royal Botanic Gardens, Kew, Missouri Botanical Garden, and mammal collections at the American Museum of Natural History. Conservation assessments by the International Union for Conservation of Nature and national agencies such as the United States Fish and Wildlife Service and Environment Agency (United Kingdom) sometimes use phylogenetic distinctiveness to prioritize protection. Phylogenetic delimitation has informed listings under legal frameworks like the Endangered Species Act and planning initiatives hosted by organizations such as BirdLife International and Conservation International.

Criticisms and limitations

Critiques have been raised in academic debates at institutions including Harvard University, University of California, Santa Cruz, and the University of Toronto, and published in journals affiliated with the Linnean Society of London and the Society for Molecular Biology and Evolution. Objections focus on potential over-splitting of taxa, conflicts with population-level processes emphasized by proponents at the Smithsonian Institution, and practical difficulties for conservation law enforcement under statutes like the Endangered Species Act. Additional limitations include incomplete lineage sorting documented by research groups at the Max Planck Institute for Evolutionary Anthropology and the Sanger Institute, and challenges in applying the concept to bacteria and archaea as discussed by researchers at the Pasteur Institute and Wadsworth Center.

Case studies and notable examples

Notable applications appear in taxonomic revisions of birds studied at the American Museum of Natural History and the Royal Ontario Museum, in plant groups revised at the Royal Botanic Gardens, Kew and the Missouri Botanical Garden, and in mammalian systematics at the Smithsonian Institution National Museum of Natural History and the Field Museum of Natural History. High-profile examples include revisions advocated by researchers associated with Cornell Lab of Ornithology and the British Ornithologists' Union, and studies of cryptic lineages published by teams from the Sanger Institute, Max Planck Institute for Evolutionary Anthropology, and University of California, Berkeley.

Category:Species concepts