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It is disputed that Wöhler's synthesis sparked the downfall of the theory of vitalism, which states that organic matter possessed a certain vital force common to all living things. Prior to the Wöhler synthesis, the work of John Dalton and Jöns Jacob Berzelius had already convinced chemists that organic and inorganic matter obey the same ...
Liebig and Wöhler recognized these as examples of structural isomerism, which was a significant advance in understanding chemical isomerism. [ 19 ] Wöhler has also been regarded as a pioneering researcher in organic chemistry as a result of his 1828 demonstration of the laboratory synthesis of urea from ammonium cyanate , in a chemical ...
Heinz Werner's orthogenetic principle is a foundation for current theories of developmental psychology [1] and developmental psychopathology. [2] [3] Initially proposed in 1940, [4] it was formulated in 1957 [5] [6] and states that "wherever development occurs it proceeds from a state of relative globality and lack of differentiation to a state of increasing differentiation, articulation, and ...
Commonly cited examples of multiple independent discovery are the 17th-century independent formulation of calculus by Isaac Newton, Gottfried Wilhelm Leibniz and others, described by A. Rupert Hall; [3] the 18th-century discovery of oxygen by Carl Wilhelm Scheele, Joseph Priestley, Antoine Lavoisier and others; and the theory of the evolution ...
Biological patterns such as animal markings, the segmentation of animals, and phyllotaxis are formed in different ways. [2]In developmental biology, pattern formation describes the mechanism by which initially equivalent cells in a developing tissue in an embryo assume complex forms and functions. [3]
Developmental systems theory (DST) is an overarching theoretical perspective on biological development, heredity, and evolution. [1] It emphasizes the shared contributions of genes , environment, and epigenetic factors on developmental processes.
Waddington introduced the concept of the epigenetic landscape, in which the state of an organism rolls "downhill" during development. In this metaphor, a canalised trait is illustrated as a valley (which he called a creode ) enclosed by high ridges, safely guiding the phenotype to its "fate".
By contrast, the constructive development perspective views the genome as a sub-system of the cell shaped by evolution to detect and respond to the signals it receives. [19] These different perspectives affect evolutionary interpretations. One example is the evolutionary significance of environmentally induced phenotypes.