Crown group - Wikipedia
In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor.
Stem Group and Crown Group Concepts - The Burgess Shale
A stem group consists entirely of extinct organisms that display some, but not all, the morphological features of their closest crown group. Studying stem group animals reveals clues to the timing and order that different features were acquired within particular lineages.
2.4 Phylogenetic Trees and Classification
In phylogenetic terminology, a crown group is a clade defined by extant species. It consists of the most recent shared common ancestor of all extant members of a clade, as well as all of the descendants of that common ancestor, whether they are still living or are extinct.
The dynamics of stem and crown groups | Science Advances
Here, we model the diversity of “stem” (basal) and “crown” (modern) members of groups using a “birth-death model,” the results of which qualitatively match many large-scale patterns seen in the fossil record.
Crown Group - an overview | ScienceDirect Topics
In phylogenetic analyses the concepts of crown, stem, and total groups provide a useful framework for navigating evolutionary trees that include fossils (Fig. 3.3; see also Fig. 1.6A). A crown group is the smallest clade that includes all living members of a group and any fossils nested within it.
The origins of crown group birds: molecules and fossils
2014年3月15日 · Knowledge of the evolutionary history of crown group birds (Neornithes) has significantly improved through emerging congruence among phylogenetic hypotheses and the description of numerous new Palaeogene stem group representatives.
Ecological innovations in the Cambrian and the origins of the crown ...
2016年1月5日 · This had the effect of smearing the appearance of the extant (i.e. crown group) phyla upwards into the Cambrian and even later (e.g. the possibility that crown group annelids and echinoderms emerged in the Ordovician), without denying the likely appearance of the largest clades of animals in the (Late) Ediacaran.
Crown Clades in Vertebrate Nomenclature: Correcting the …
2008年2月1日 · A crown group is defined as the most recent common ancestor of at least two extant groups and all its descendants (Gauthier, 1986). Despite criticism, crown-group definitions are widely used, especially for certain clades of vertebrates.
Diversification dynamics of total-, stem-, and crown-groups are
2021年6月11日 · We asked what range of total-group ages can be generated under a fixed crown-group age with constant rates of speciation and extinction; this experiment explores whether the crown-group can be expected to approximate the age of the total-group.
The dynamics of stem and crown groups - PMC - National Center …
2020年2月19日 · Here, we model the diversity of “stem” (basal) and “crown” (modern) members of groups using a “birth-death model,” the results of which qualitatively match many large-scale patterns seen in the fossil record.
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