Fisherian runaway

runaway evolutionrunaway selectionFisher's runaway modelFisherian runaway selectionFisherian sexual selectionrunaway co-evolutionrunaway effectrunaway sexual selectionselective runaway process
Fisherian runaway or runaway selection is a sexual selection mechanism proposed by the mathematical biologist Ronald Fisher in the early 20th century, to account for the evolution of exaggerated male ornamentation by persistent, directional female choice.wikipedia
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Sexual selection

sexually selectedmale-male competitionintrasexual selection
Fisherian runaway or runaway selection is a sexual selection mechanism proposed by the mathematical biologist Ronald Fisher in the early 20th century, to account for the evolution of exaggerated male ornamentation by persistent, directional female choice.
Sexual selection can lead males to extreme efforts to demonstrate their fitness to be chosen by females, producing sexual dimorphism in secondary sexual characteristics, such as the ornate plumage of birds such as birds of paradise and peafowl, or the antlers of deer, or the manes of lions, caused by a positive feedback mechanism known as a Fisherian runaway, where the passing-on of the desire for a trait in one sex is as important as having the trait in the other sex in producing the runaway effect.

Mate choice

mate selectionfemale choicemate preference
Fisherian runaway or runaway selection is a sexual selection mechanism proposed by the mathematical biologist Ronald Fisher in the early 20th century, to account for the evolution of exaggerated male ornamentation by persistent, directional female choice.
These are direct phenotypic benefits, sensory bias, the Fisherian runaway hypothesis, indicator traits and genetic compatibility.

Biological ornament

ornamentationornamentsornament
Fisherian runaway or runaway selection is a sexual selection mechanism proposed by the mathematical biologist Ronald Fisher in the early 20th century, to account for the evolution of exaggerated male ornamentation by persistent, directional female choice.
As Ronald Fisher noted, the male offspring will inherit the ornament while the female offspring will inherit the preference for said ornament, which can lead to a positive feedback loop known as a Fisherian runaway.

Natural selection

selectionselectiveselected
An example is the colourful and elaborate peacock plumage compared to the relatively subdued peahen plumage; the costly ornaments, notably the bird's extremely long tail, appear to be incompatible with natural selection.
Phenotypic traits can be displayed in one sex and desired in the other sex, causing a positive feedback loop called a Fisherian runaway, for example, the extravagant plumage of some male birds such as the peacock.

Ronald Fisher

R.A. FisherR. A. FisherFisher
Fisherian runaway or runaway selection is a sexual selection mechanism proposed by the mathematical biologist Ronald Fisher in the early 20th century, to account for the evolution of exaggerated male ornamentation by persistent, directional female choice.
He outlined Fisher's principle, the Fisherian runaway and sexy son hypothesis theories of sexual selection.

The Genetical Theory of Natural Selection

Fisher, in the foundational 1930 book, The Genetical Theory of Natural Selection, first outlined a model by which runaway inter-sexual selection could lead to sexually dimorphic male ornamentation based upon female choice and a preference for "attractive" but otherwise non-adaptive traits in male mates.
It is commonly cited in biology books, outlining many concepts that are still considered important such as Fisherian runaway, Fisher's principle, reproductive value, Fisher's fundamental theorem of natural selection, Fisher's geometric model, the sexy son hypothesis, mimicry and the evolution of dominance.

Secondary sex characteristic

secondary sexual characteristicsecondary sex characteristicssecondary sexual characteristics
These characteristics are believed to be produced by a positive feedback loop known as the Fisherian runaway produced by the secondary characteristic in one sex and the desire for that characteristic in the other sex.

Sexy son hypothesis

good genesgood genes hypothesisgood genes theory
The sexy son hypothesis (also proposed by Fisher) suggests that females that choose desirably ornamented males will have desirably ornamented (or sexy) sons, and that the effect of that behaviour on spreading the female's genes through subsequent generations may outweigh other factors such as the level of parental investment by the father.
generating genetic coupling that will drive self-reinforcing coevolution of both trait and preference, due to the mating advantage of males with the trait, creating a Fisherian runaway sexy sons process.

Evolution

evolvedtheory of evolutionevolutionary
Fisherian runaway or runaway selection is a sexual selection mechanism proposed by the mathematical biologist Ronald Fisher in the early 20th century, to account for the evolution of exaggerated male ornamentation by persistent, directional female choice.

Peafowl

peacockpeacockspeacock feather
An example is the colourful and elaborate peacock plumage compared to the relatively subdued peahen plumage; the costly ornaments, notably the bird's extremely long tail, appear to be incompatible with natural selection.

Plumage

eclipse plumageplumesalbinism in birds
An example is the colourful and elaborate peacock plumage compared to the relatively subdued peahen plumage; the costly ornaments, notably the bird's extremely long tail, appear to be incompatible with natural selection.

Sexual dimorphism

sexually dimorphicdimorphicdimorphism
Fisherian runaway can be postulated to include sexually dimorphic phenotypic traits such as behaviour expressed by either sex.

Phenotypic trait

traittraitscharacters
Fisherian runaway can be postulated to include sexually dimorphic phenotypic traits such as behaviour expressed by either sex.

Paradox

paradoxesparadoxicallogical paradox
Extreme and apparently maladaptive sexual dimorphism represented a paradox for evolutionary biologists from Charles Darwin's time up to the modern synthesis.

Charles Darwin

DarwinDarwinianCharles Robert Darwin
Extreme and apparently maladaptive sexual dimorphism represented a paradox for evolutionary biologists from Charles Darwin's time up to the modern synthesis. Charles Darwin published a book on sexual selection in 1871 called The Descent of Man, and Selection in Relation to Sex, which garnered interest upon its release but by the 1880s the ideas had been deemed too controversial and were largely neglected. The plumage dimorphism of the peacock and peahen of the species within the genus Pavo is a prime example of the ornamentation paradox that has long puzzled evolutionary biologists; Darwin wrote in 1860: The sight of a feather in a peacock’s tail, whenever I gaze at it, makes me sick!

Modern synthesis (20th century)

modern synthesismodern evolutionary synthesisevolutionary synthesis
Extreme and apparently maladaptive sexual dimorphism represented a paradox for evolutionary biologists from Charles Darwin's time up to the modern synthesis.

Fitness (biology)

fitnessbiological fitnessreproductive fitness
Fisher developed the theory further by assuming genetic correlation between the preference and the ornament, that initially the ornament signalled greater potential fitness (the likelihood of leaving more descendants), so preference for the ornament had a selective advantage.

Positive feedback

positive feedback looppositiveexacerbated
Over subsequent generations this could lead to runaway selection by positive feedback, and the speed with which the trait and the preference increase could (until counter-selection interferes) increase exponentially ("geometrically").

Exponential growth

exponentiallyexponentialgrow exponentially
Over subsequent generations this could lead to runaway selection by positive feedback, and the speed with which the trait and the preference increase could (until counter-selection interferes) increase exponentially ("geometrically").

The Descent of Man, and Selection in Relation to Sex

The Descent of ManDescent of ManThe Descent of Man and Selection in Relation to Sex
Charles Darwin published a book on sexual selection in 1871 called The Descent of Man, and Selection in Relation to Sex, which garnered interest upon its release but by the 1880s the ideas had been deemed too controversial and were largely neglected.

Alfred Russel Wallace

WallaceAlfred WallaceA. R. Wallace
Alfred Russel Wallace disagreed with Darwin, particularly after Darwin's death, that sexual selection was a real phenomenon.

Pavo (genus)

PavoPavo'' (genus)
The plumage dimorphism of the peacock and peahen of the species within the genus Pavo is a prime example of the ornamentation paradox that has long puzzled evolutionary biologists; Darwin wrote in 1860: The sight of a feather in a peacock’s tail, whenever I gaze at it, makes me sick!

Population

populationspopulacepopulated
Fisher suggested that any visible features that indicate fitness, that are not themselves adaptive, that draw attention, and that vary in their appearance amongst the population of males so that the females can easily compare them, would be enough to initiate Fisherian runaway.

Sandgrouse

PteroclidaePterocliformessand grouse
Such arbitrariness is borne out by mathematical modelling, and by observation of isolated populations of sandgrouse, where the males can differ markedly from those in other populations.

Heritability

heritablebreeder's equationheritabilities
Fisherian runaway assumes that sexual preference in females and ornamentation in males are both genetically variable (heritable).