title: Progress to extinction: increased specialisation causes the demise of animal clades.
abstract: Animal clades tend to follow a predictable path of waxing and waning during their existence, regardless of their total species richness or geographic coverage. Clades begin small and undifferentiated, then expand to a peak in diversity and range, only to shift into a rarely broken decline towards extinction. While this trajectory is now well documented and broadly recognised, the reasons underlying it remain obscure. In particular, it is unknown why clade extinction is universal and occurs with such surprising regularity. Current explanations for paleontological extinctions call on the growing costs of biological interactions, geological accidents, evolutionary traps, and mass extinctions. While these are effective causes of extinction, they mainly apply to species, not clades. Although mass extinctions is the undeniable cause for the demise of a sizeable number of major taxa, we show here that clades escaping them go extinct because of the widespread tendency of evolution to produce increasingly specialised, sympatric, and geographically restricted species over time.
authors: Department of Earth Science, Environment and Resources, University of Naples Federico II, 80138 Napoli, Italy.
authors: P
authors: P
authors: Raia
authors: Department of Earth Science, Environment and Resources, University of Naples Federico II, 80138 Napoli, Italy.
authors: F
authors: F
authors: Carotenuto
authors: Department of Earth Science, Environment and Resources, University of Naples Federico II, 80138 Napoli, Italy.
authors: A
authors: A
authors: Mondanaro
authors: Department of Earth Science, Environment and Resources, University of Naples Federico II, 80138 Napoli, Italy.
authors: S
authors: S
authors: Castiglione
authors: Department of Earth Science, Environment and Resources, University of Naples Federico II, 80138 Napoli, Italy.
authors: F
authors: F
authors: Passaro
authors: Department of Earth Science, Environment and Resources, University of Naples Federico II, 80138 Napoli, Italy.
authors: F
authors: F
authors: Saggese
authors: Department of Earth Science, Environment and Resources, University of Naples Federico II, 80138 Napoli, Italy.
authors: M
authors: M
authors: Melchionna
authors: Department of Earth Science, Environment and Resources, University of Naples Federico II, 80138 Napoli, Italy.
authors: C
authors: C
authors: Serio
authors: Department of Earth Science, Environment and Resources, University of Naples Federico II, 80138 Napoli, Italy.
authors: L
authors: L
authors: Alessio
authors: Department of Biological and Environmental Sciences, University of Gothenburg, 413 19 Gothenburg, Sweden.
authors: D
authors: D
authors: Silvestro
authors: Department of Geosciences and Geography, P.O. Box 64, FI-00014 University of Helsinki, Finland.|Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, NO-0316 Oslo, Norway.
authors: M
authors: M
authors: Fortelius
mesh_terms: D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D016208:Databases, Factual; D053476:Extinction, Biological; D005580:Fossils; D049810:Genetic Speciation; D008390:Markov Chains; D008954:Models, Biological; D010163:Paleontology; D061350:Sympatry