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Circular diagrams are often used in phylogenetics, especially for the graphical representation of phylogenetic relationships. Evolutionary trees often encompass numerous species that are conveniently shown on a circular tree, with images of the species shown on the periphery of a tree. Such diagrams have been called phylogenetic mandalas. [33]
The Specie Circular is a United States presidential executive order issued by President Andrew Jackson on 11 July 1836 pursuant to the Coinage Act of 1834. It required payment for government land to be in gold and silver (specie). [1] It was repealed by a joint act of Congress on 21 May 1838. [2]
Social cycle theories are among the earliest social theories in sociology.Unlike the theory of social evolutionism, which views the evolution of society and human history as progressing in some new, unique direction(s), sociological cycle theory argues that events and stages of society and history generally repeat themselves in cycles.
The evolutionary history of species has been described as a "tree" with many branches arising from a single trunk. While Haeckel's tree is outdated, it illustrates clearly the principles that more complex and accurate modern reconstructions can obscure.
A phylogenetic tree, phylogeny or evolutionary tree is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time. [ 1 ] [ 2 ] In other words, it is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon ...
Species go extinct constantly as environments change, as organisms compete for environmental niches, and as genetic mutation leads to the rise of new species from older ones. At long irregular intervals, Earth's biosphere suffers a catastrophic die-off, a mass extinction , [ 9 ] often comprising an accumulation of smaller extinction events over ...
Edward Hitchcock's fold-out paleontological chart in his 1840 Elementary Geology. Although tree-like diagrams have long been used to organise knowledge, and although branching diagrams known as claves ("keys") were omnipresent in eighteenth-century natural history, it appears that the earliest tree diagram of natural order was the 1801 "Arbre botanique" (Botanical Tree) of the French ...
Porphyrian trees by three authors: Purchotius (1730), Boethius (6th century), and Ramon Llull (ca. 1305). In philosophy (particularly the theory of categories), the Porphyrian tree or Tree of Porphyry is a classic device for illustrating a "scale of being" (Latin: scala praedicamentalis), attributed to the 3rd-century CE Greek neoplatonist philosopher and logician Porphyry, and revived through ...