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In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, and synapomorphy all mean a trait shared between species because they share an ancestral species.
Examples of symplectomorphisms include the canonical transformations of classical mechanics and theoretical physics, the flow associated to any Hamiltonian function, the map on cotangent bundles induced by any diffeomorphism of manifolds, and the coadjoint action of an element of a Lie group on a coadjoint orbit.
Symplesiomorphy – an ancestral trait shared by two or more taxa. Plesiomorphy – a symplesiomorphy discussed in reference to a more derived state. Pseudoplesiomorphy – a trait that cannot be identified as either a plesiomorphy or an apomorphy that is a reversal. [15]
Since cold-bloodedness is a plesiomorphy, inherited from the common ancestor of traditional reptiles and birds, and thus a symplesiomorphy of turtles, snakes and crocodiles (among others), it does not mean that turtles, snakes and crocodiles form a clade that excludes the birds. An apomorphy ("separate form") or derived state is an innovation.
When looking at the theory of symmorphosis, one must consider if the design in the organism is fully optimized. [3] The structural design in terms of symmorphosis means that the organ is designed to allow full capacity of its function and can allow for adjustments to occur when necessary. [5]
Nursing theory is defined as "a creative and conscientious structuring of ideas that project a tentative, purposeful, and systematic view of phenomena". [1] Through systematic inquiry, whether in nursing research or practice, nurses are able to develop knowledge relevant to improving the care of patients.
The terms "plesiomorphy" and "apomorphy" are typically used in the technical literature: for example, when a plesiomorphic trait is shared by more than one member of a clade, the trait is called a symplesiomorphy, that is, a shared primitive trait; a shared derived trait is a synapomorphy.
In 1930, Hennig skipped a year, and graduated on 26 February 1932. As early as 1931, Willi Hennig composed an essay entitled Die Stellung der Systematik in der Zoologie ("The state of systematics in zoology") as part of his school work, published posthumously in 1978. It showed his interest as well as his deliberate treatment of systematic ...