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The mediaeval great chain of being as a staircase, implying the possibility of progress: [1] Ramon Lull's Ladder of Ascent and Descent of the Mind, 1305. Alternatives to Darwinian evolution have been proposed by scholars investigating biology to explain signs of evolution and the relatedness of different groups of living things.
In biology, polymorphism [1] is the occurrence of two or more clearly different morphs or forms, also referred to as alternative phenotypes, in the population of a species. To be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating).
Mutationism is one of several alternatives to evolution by natural selection that have existed both before and after the publication of Charles Darwin's 1859 book On the Origin of Species. In the theory, mutation was the source of novelty, creating new forms and new species, potentially instantaneously, [ 1 ] in sudden jumps. [ 2 ]
Phenotypic variation (due to underlying heritable genetic variation) is a fundamental prerequisite for evolution by natural selection. It is the living organism as a whole that contributes (or not) to the next generation, so natural selection affects the genetic structure of a population indirectly via the contribution of phenotypes.
Alternative explanations for the punctuated pattern of evolution observed in the fossil record. Both macromutation and seemingly "rapid" episodes of gradual evolution could give the appearance of instantaneous change, since 10,000 years seldom registers in the geological record.
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype.It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations.
In evolutionary biology, a spandrel is a phenotypic trait that is a byproduct of the evolution of some other characteristic, rather than a direct product of adaptive selection. Stephen Jay Gould and Richard Lewontin brought the term into biology in their 1979 paper " The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the ...
These phenotypic differences undergo selection; as genotypic differences narrow, the trait becomes: Genetically fixed (non-responsive to environmental conditions) Polyphenic (responsive to environmental conditions) Evolution of novel polyphenisms through this mechanism has been demonstrated in the laboratory.