Vicar of Bray (scientific hypothesis)
Encyclopedia
The "Vicar of Bray" is the name given to a hypothesis
attempting to explain why sexual reproduction
might be favoured over asexual reproduction
, in which sexual populations are able to outcompete asexual populations because they evolve
more rapidly in response to environmental changes. The offspring of a population of sexually reproducing individuals will show a more varied selection of phenotype
s and that they will therefore be more likely to produce a strain that can survive a change in the ecology of the environment in which they live. Under the Vicar of Bray hypothesis, sex benefits a population as a whole, but not individuals within it, making it a case of group selection
.
The theory was named after The Vicar of Bray
, a supposed cleric who retained his ecclesiastic office
by quickly adapting to the prevailing religious winds, switching between Protestant
and Catholic
rites as the ruling monarch changed. A mathematized version of this theory was accepted by most biologists as being one of the most important reasons for the prevalence of sexual reproduction in the natural world until the implicit group selectionist character of the argument was re-examined in the course of the Williams Revolution (i.e. George C. Williams
's critiques of group selection, which led to a gene-centered view of evolution
). However, a more popular explanation for the evolutionary origin and maintenance of sex is currently the Red Queen Hypothesis, which instead proposes that sex benefits individuals directly.
Hypothesis
A hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...
attempting to explain why sexual reproduction
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
might be favoured over asexual reproduction
Asexual reproduction
Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy reduction, or fertilization. A more stringent definition is agamogenesis which is reproduction without...
, in which sexual populations are able to outcompete asexual populations because they evolve
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
more rapidly in response to environmental changes. The offspring of a population of sexually reproducing individuals will show a more varied selection of phenotype
Phenotype
A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...
s and that they will therefore be more likely to produce a strain that can survive a change in the ecology of the environment in which they live. Under the Vicar of Bray hypothesis, sex benefits a population as a whole, but not individuals within it, making it a case of group selection
Group selection
In evolutionary biology, group selection refers to the idea that alleles can become fixed or spread in a population because of the benefits they bestow on groups, regardless of the alleles' effect on the fitness of individuals within that group....
.
The theory was named after The Vicar of Bray
The Vicar of Bray
The Vicar of Bray is a satirical description of an individual fundamentally changing his principles to remain in ecclesiastical office as external requirements change around him...
, a supposed cleric who retained his ecclesiastic office
Clergy
Clergy is the generic term used to describe the formal religious leadership within a given religion. A clergyman, churchman or cleric is a member of the clergy, especially one who is a priest, preacher, pastor, or other religious professional....
by quickly adapting to the prevailing religious winds, switching between Protestant
Protestantism
Protestantism is one of the three major groupings within Christianity. It is a movement that began in Germany in the early 16th century as a reaction against medieval Roman Catholic doctrines and practices, especially in regards to salvation, justification, and ecclesiology.The doctrines of the...
and Catholic
Catholicism
Catholicism is a broad term for the body of the Catholic faith, its theologies and doctrines, its liturgical, ethical, spiritual, and behavioral characteristics, as well as a religious people as a whole....
rites as the ruling monarch changed. A mathematized version of this theory was accepted by most biologists as being one of the most important reasons for the prevalence of sexual reproduction in the natural world until the implicit group selectionist character of the argument was re-examined in the course of the Williams Revolution (i.e. George C. Williams
George C. Williams
Professor George Christopher Williams was an American evolutionary biologist.Williams was a professor emeritus of biology at the State University of New York at Stony Brook. He was best known for his vigorous critique of group selection. The work of Williams in this area, along with W. D...
's critiques of group selection, which led to a gene-centered view of evolution
Gene-centered view of evolution
The gene-centered view of evolution, gene selection theory or selfish gene theory holds that evolution occurs through the differential survival of competing genes, increasing the frequency of those alleles whose phenotypic effects successfully promote their own propagation, with gene defined as...
). However, a more popular explanation for the evolutionary origin and maintenance of sex is currently the Red Queen Hypothesis, which instead proposes that sex benefits individuals directly.