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Evolutionary progress as a tree of life. Ernst Haeckel, 1866 Lamarck's two-factor theory involves 1) a complexifying force that drives animal body plans towards higher levels (orthogenesis) creating a ladder of phyla, and 2) an adaptive force that causes animals with a given body plan to adapt to circumstances (use and disuse, inheritance of acquired characteristics), creating a diversity of ...
The sloshing bucket model of evolution is a theory in evolutionary biology that describes how environmental disturbances varying in magnitude will affect the species present. [ 1 ] [ 2 ] [ 3 ] The theory emphasizes the causal relationship between environmental factors that impinge and affect genealogical systems, providing an overarching view ...
Techniques from evolutionary algorithms applied to the modeling of biological evolution are generally limited to explorations of microevolutionary processes and planning models based upon cellular processes. In most real applications of EAs, computational complexity is a prohibiting factor. [3]
Neutral theory – Theory of evolution by changes at the molecular level; Shifting balance theory – One version of the theory of evolution; Price equation – Description of how a trait or gene changes in frequency over time; Coefficient of relationship – Measure of biological relationship between individuals
The evolution of biological complexity is one important outcome of the process of evolution. [1] Evolution has produced some remarkably complex organisms – although the actual level of complexity is very hard to define or measure accurately in biology, with properties such as gene content, the number of cell types or morphology all proposed as possible metrics.
In 1985, biologist Robert G. B. Reid authored Evolutionary Theory: The Unfinished Synthesis, which argued that the modern synthesis with its emphasis on natural selection is an incomplete picture of evolution, and emergent evolution can explain the origin of genetic variation.
Ohno presented the first version of the 2R hypothesis as part of his larger argument for the general importance of gene duplication in evolution.Based on relative genome sizes and isozyme analysis, he suggested that ancestral fish or amphibians had undergone at least one and possibly more cases of "tetraploid evolution".
Evolution has been described as "fact and theory"; "fact, not theory"; "only a theory, not a fact"; "multiple theories, not fact"; and "neither fact, nor theory." [ 2 ] The disagreements among these statements, however, have more to do with the meaning of words than the substantial issues and this controversy is discussed below.