Disruptive selection: Difference between revisions

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== Disruptive Selection ==


'''Disruptive selection''', also known as '''diversifying selection''', is a type of [[natural selection]] that simultaneously favors individuals at both extremes of the distribution over individuals with intermediate phenotypes. This evolutionary process is significant because it can lead to the emergence of new [[species]] through [[speciation]], particularly when the environmental conditions support multiple phenotypes.
[[File:Genetic_Distribution.svg|thumb|right|300px|Illustration of disruptive selection showing the shift in population distribution.]]


In disruptive selection, environmental conditions or ecological niches allow individuals with extreme traits to have a higher [[fitness]] compared to those in the middle of the trait spectrum. This can result in a bimodal distribution of traits within a population, where the two extremes become more common and the intermediate forms are less common or even eliminated.
'''Disruptive selection''' is a type of [[natural selection]] that simultaneously favors individuals at both extremes of the distribution. This form of selection can lead to a bimodal distribution of traits within a population, where two distinct phenotypes are favored over the intermediate phenotype.


==Mechanism==
=== Mechanism ===
The mechanism of disruptive selection involves different factors that can influence the fitness of individuals within a population. These factors include but are not limited to, [[predation]], [[competition]] for resources, and [[habitat]] specialization. For example, in a habitat where resources are available in two distinct forms, individuals specialized in exploiting one or the other resource form may have a survival advantage over those that are not specialized.
Disruptive selection occurs when environmental conditions favor individuals at both extremes of a phenotypic range. This can happen in environments that are heterogeneous or where there are distinct niches that different phenotypes can exploit. For example, in a population of birds, if both very large and very small beaks are advantageous for accessing different types of food, individuals with intermediate beak sizes may be at a disadvantage.


==Examples==
=== Examples ===
One classic example of disruptive selection is the case of the [[Galápagos Islands]]' finches, studied by [[Charles Darwin]]. In environments where medium-sized seeds were scarce but small and large seeds were abundant, finches with either particularly large or small beaks had a survival advantage over those with medium-sized beaks. This led to an increase in the frequency of both large and small beaked birds, while medium-sized beaked birds became less common.
One classic example of disruptive selection is seen in the [[Darwin's finches]] on the [[Galápagos Islands]]. In some species, finches with either very large or very small beaks have a selective advantage, as they can access different food sources more effectively than those with medium-sized beaks.


Another example can be found in certain species of [[butterflies]], where individuals with either very pale or very dark wing colors are favored in certain habitats, but those with intermediate colors are more easily preyed upon.
Another example can be found in the [[African seedcracker]] finch, where individuals with either very large or very small beaks are more successful in cracking different types of seeds, leading to a bimodal distribution of beak sizes.


==Consequences==
=== Implications ===
The consequences of disruptive selection can be profound, leading to increased [[genetic diversity]] within a population and potentially the formation of new species. If the diverging subpopulations become reproductively isolated, for instance, through [[geographic isolation]] or differences in mating behavior, this can lead to [[allopatric speciation]] or [[sympatric speciation]], respectively.
Disruptive selection can lead to increased [[genetic diversity]] within a population and may even result in [[speciation]] if the two extreme phenotypes become reproductively isolated from each other. This form of selection is a key mechanism in the process of [[adaptive radiation]], where a single ancestral species gives rise to a variety of new species adapted to different environments.


==See also==
== Related Pages ==
* [[Directional selection]]
* [[Natural selection]]
* [[Stabilizing selection]]
* [[Speciation]]
* [[Sexual selection]]
* [[Adaptive radiation]]
* [[Artificial selection]]
* [[Darwin's finches]]
* [[Genetic diversity]]


[[Category:Evolutionary biology]]
[[Category:Evolutionary biology]]
[[Category:Natural selection]]
{{biology-stub}}

Latest revision as of 06:24, 16 February 2025

Disruptive Selection[edit]

Illustration of disruptive selection showing the shift in population distribution.

Disruptive selection is a type of natural selection that simultaneously favors individuals at both extremes of the distribution. This form of selection can lead to a bimodal distribution of traits within a population, where two distinct phenotypes are favored over the intermediate phenotype.

Mechanism[edit]

Disruptive selection occurs when environmental conditions favor individuals at both extremes of a phenotypic range. This can happen in environments that are heterogeneous or where there are distinct niches that different phenotypes can exploit. For example, in a population of birds, if both very large and very small beaks are advantageous for accessing different types of food, individuals with intermediate beak sizes may be at a disadvantage.

Examples[edit]

One classic example of disruptive selection is seen in the Darwin's finches on the Galápagos Islands. In some species, finches with either very large or very small beaks have a selective advantage, as they can access different food sources more effectively than those with medium-sized beaks.

Another example can be found in the African seedcracker finch, where individuals with either very large or very small beaks are more successful in cracking different types of seeds, leading to a bimodal distribution of beak sizes.

Implications[edit]

Disruptive selection can lead to increased genetic diversity within a population and may even result in speciation if the two extreme phenotypes become reproductively isolated from each other. This form of selection is a key mechanism in the process of adaptive radiation, where a single ancestral species gives rise to a variety of new species adapted to different environments.

Related Pages[edit]