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In 1973, M. J. D. White, then at the end of a long career investigating karyotypes, gave an interesting summary of the distribution of chromosome polymorphism. "It is extremely difficult to get an adequate idea as to what fraction of the species of eukaryote organisms actually are polymorphic for structural rearrangements of the chromosomes.
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).
This condition has been detected in many species. Trichomycterus davisi, for example, is an extreme case where the polymorphism was present within a single chimeric individual. [1] It has also been studied in alfalfa, [2] shrews, [3] Brazilian rodents, [4] and an enormous variety of other animals and plants. [5] In one instance it has been ...
Foster's rule, also known as the island rule or the island effect, is an ecogeographical rule in evolutionary biology stating that members of a species get smaller or bigger depending on the resources available in the environment. For example, it is known that pygmy mammoths evolved from normal mammoths on small islands.
Genetic polymorphism and natural selection give rise to otherwise edible species (the mimic) gaining a survival advantage by resembling inedible species (the model). Such a mimicry complex is referred to as Batesian and is most commonly known by the mimicry by the limenitidine viceroy butterfly of the inedible danaine monarch. Later research ...
It operates on polymorphic species, species which have different forms. In apostatic selection, the common forms of a species are preyed on more than the rarer forms, giving the rare forms a selective advantage in the population. [1] It has also been discussed that apostatic selection acts to stabilize prey polymorphisms.
The World's 100 most threatened species [1] is a compilation of the most threatened animals, plants, and fungi in the world. It was the result of a collaboration between over 8,000 scientists from the International Union for Conservation of Nature Species Survival Commission (IUCN SSC), along with the Zoological Society of London . [ 2 ]
Breeding in a number of animal and plant species has been revolutionized by the emergence of SNP arrays. The method is based on the prediction of genetic merit by incorporating relationships among individuals based on SNP array data. [13] This process is known as genomic selection. Crop-specific arrays find use in agriculture. [14] [15]