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Foster's rule, the island rule, or the island effect states that members of a species get smaller or bigger depending on the resources available in the environment. [ 28 ] [ 29 ] [ 30 ] The rule was first stated by J. Bristol Foster in 1964 in the journal Nature , in an article titled "The evolution of mammals on islands".
The green box (central) may represent an evolutionary grade (paraphyletic), a group united by conservative anatomical and physiological traits rather than phylogeny. The flanking red and blue boxes are clades (i.e., complete monophyletic subtrees). A grade is a taxon united by a level of morphological or physiological complexity.
In maximum parsimony, Dollo parsimony refers to a model whereby a characteristic is gained only one time and can never be regained if it is lost. [8] For example, the evolution and repeated loss of teeth in vertebrates could be well-modeled under Dollo parsimony, whereby teeth made from hydroxyapatite evolved only once at the origin of vertebrates, and were then lost multiple times, in birds ...
Bergmann's rule is an ecogeographical rule that states that, within a broadly distributed taxonomic clade, populations and species of larger size are found in colder environments, while populations and species of smaller size are found in warmer regions. The rule derives from the relationship between size in linear dimensions meaning that both ...
Jordan's rule (sense 1) is an ecogeographical rule that describes the inverse relationship between water temperature and meristic characteristics in various species of fish. The most commonly observed relationship is that fin ray , vertebrae , or scale numbers increase with decreasing temperature.
Biological rules describe patterns of variation within and across species most often in regard to size. While they are described as rules there are often many ...
Lipinski's rule of five, also known as Pfizer's rule of five or simply the rule of five (RO5), is a rule of thumb to evaluate druglikeness or determine if a chemical compound with a certain pharmacological or biological activity has chemical properties and physical properties that would likely make it an orally active drug in humans.
This "rule" comments on the fact that there are a great number of proteins in all organisms which fulfil a number of different functions through modifying chemical or physical processes. An example would be an enzyme that catalyses a chemical reaction that would take place too slowly to benefit an organism without being sped up by this enzyme.