E.E. Sotka, in Encyclopedia of Ecology, 2008 A cline is a gradient of a phenotypic or genetic character within a single species. The geographic distances across which characters shift can range from meters to thousands of kilometers.
What is a cline?
First coined by Julian Huxley in 1938, the "character" of the cline referred to is usually genetic (e.g. allele frequency, blood type ), or phenotypic (e.g. body size, skin pigmentation). Clines can show smooth, continuous gradation in a character, or they may show more abrupt changes in the trait from one geographic region to the next. [2]
What is the difference between an ecotype and a cline?
Cline (biology) While the terms “ ecotype ” and “cline” are sometimes used interchangeably, they do in fact differ in that “ecotype” refers to a population which differs from other populations in a number of characters, rather than the single character that varies amongst populations in a cline.
What is the difference between a cline and a gradient?
Clines can show smooth, continuous gradation in a character, or they may show more abrupt changes in the trait from one geographic region to the next. A cline refers to a spatial gradient in a specific, singular trait, rather than a gradient in a population as a whole.
What is a cline According to Huxley?
Cline (biology) Because of this, clines were defined by Huxley as being an “auxiliary taxonomic principle”; that is, clinal variation in a species is not awarded taxonomic recognition in the way subspecies or species are.
What is cline theory?
Classical cline theory interprets clines as speciation processes in two stages: (1) smooth clines, typical of species with no marked subspecies, and (2) stepped clines, characteristic of species with marked subspecies, separated by hybrid zones, where the clines are steeper than within the areas of the subspecies.
What is cline and its example?
A cline is the specific set of traits in a population of a given species that have been influenced by the local environment. For example, a population of warm-blooded animals that lived in a cooler climate closer to the North Pole would have larger bodies, allowing them to better conserve heat.
What is a geographic cline?
Geographic cline analysis provides a potential framework for integrating diverse forms of data in a spatially explicit framework, but has not been used to study genome-wide patterns of divergence.
What is a cline AP biology?
In biology, a cline (from the Greek κλίνειν klinein, meaning "to lean") is a measurable gradient in a single character (or biological trait) of a species across its geographical range.
What is a cline in simple terms?
Definition of cline (Entry 1 of 2) : a gradient of morphological or physiological change in a group of related organisms usually along a line of environmental or geographic transition.
What is a cline quizlet?
Cline is a gradual change in characteristics from one population to another. Specific traits following a geographical continuum are called a cline.
What is a genomic cline?
Genomic cline analysis explicitly compares allele or genotype frequencies of each locus (or locus-specific ancestry) to a genome-wide average representing the genomic ancestry of an individual or population (Gompert and Buerkle 2011).
What is a cline and why is it important for our understanding of human variation?
A cline is a gradation in the frequency of an allele/trait between populations living in different geographic regions. In order to study human traits that are clinally distributed, it is often required to perform genetic testing to uncover the true frequencies of an allele or trait across a certain geographic space.
Why does the existence of a cline suggest natural selection?
Why does the existence of a cline suggest natural selection? Some clines are produced by a gradation in an environmental variable, such as temperature. The existence of a cline suggests natural selection because of the close association between the environmental variable and the frequency of the allele.
What external factors produce a cline?
What external factors might produce a cline? A cline is a graded change in a character along a geographic axis. Some clines are produced by a gradation in an environmental variable, as illustrated by the impact of temperature on the frequency of a cold-adaptive allele in mummichog fish.
What is an ecotype in ecology?
An ecotype is a population (or subspecies or race) that is adapted to local environmental conditions. The implication is that those individuals which were best adapted to the prevailing conditions left the most offspring.
What is genetic drift bottleneck effect?
The bottleneck effect is an extreme example of genetic drift that happens when the size of a population is severely reduced. Events like natural disasters (earthquakes, floods, fires) can decimate a population, killing most individuals and leaving behind a small, random assortment of survivors.
What is a cline in math?
Cline (mathematics) or generalised circle, a circle or straight line in inverse geometry.
What is Cline activity?
ACTIVITY – WORD CLINE A word cline is a graded sequence of words whose meanings span across a continuum of meanings on a sloping line. This activity expands students' vocabulary and to discover shades of meaning between words. It is a great way to introduce language embedded within a genre.
What is a Cline anthropology?
What are clines? In anthropology we talk about clinal variation. Cline is a term that was devised by the biologist Julian Huxley to represent a geographical gradient in a particular trait across a species.
What is language Cline?
A cline is a scale of language items that goes from one extreme to another, for example, from positive to negative, or from weak to strong.
What is a cline in biology?
A cline refers to a spatial gradient in a specific, singular trait, rather than a collection of traits; a single population can therefore have as many clines as it has traits, at least in principle. Additionally, Huxley recognised that these multiple independent clines may not act in concordance with each other.
What is a cline character?
First coined by Julian Huxley in 1938, the “character” of the cline referred to is usually genetic (e.g. allele frequency, blood type ), or phenotypic (e.g. body size, skin pigmentation). Clines can show smooth, continuous gradation in a character, or they may show more abrupt changes in the trait from one geographic region to the next.
How does selection maintain clines?
The mechanism of selection maintaining the clines in this scenario is often intrinsic. This means that the fitness of individuals is independent of the external environment, and selection is instead dependent on the genome of the individual. Intrinsic, or endogenous, selection can give rise to clines in characters through a variety of mechanisms. One way it may act is through heterozygote disadvantage, in which intermediate genotypes have a lower relative fitness than either homozygote genotypes. Because of this disadvantage, one allele will tend to become fixed in a given population, such that populations will consist largely of either AA ( homozygous dominant) or aa (homozygous recessive) individuals. The cline of heterozygotes that is created when these respective populations come into contact is then shaped by the opposing forces of selection and gene flow; even if selection against heterozygotes is great, if there is some degree of gene flow between the two populations, then a steep cline may be able to be maintained. Because instrinsic selection is independent of the external environment, clines generated by selection against hybrids are not fixed to any given geographical area and can move around the geographic landscape. Such hybrid zones where hybrids are a disadvantage relative to their parental lines (but which are nonetheless maintained through selection being counteracted by gene flow) are known as “tension zones”.
How are clines generated?
Clines generated through this mechanism have arisen through the joining of two formerly isolated populations which differentiated in allopatry, creating an intermediate zone. This secondary contact scenario may occur, for example, when climatic conditions change, allowing the ranges of populations to expand and meet. Because over time the effect of gene flow will tend to eventually swamp out any regional differences and cause one large homogenous population, for a stable cline to be maintained when two populations join there must usually be a selective pressure maintaining a degree of differentiation between the two populations.
What is a cline in baseball?
In biology, a cline (from the Greek κλίνειν klinein, meaning "to lean") is a measurable gradient in a single character (or biological trait) of a species across its geographical range. First coined by Julian Huxley in 1938, the “character” ...
Why is a stable cline maintained when two populations join?
Because over time the effect of gene flow will tend to eventually swamp out any regional differences and cause one large homogenous population, for a stable cline to be maintained when two populations join there must usually be a selective pressure maintaining a degree of differentiation between the two populations.
How do clinal characters change?
Clinal characters change from one end of the geographic range to another. The extent of this change is reflected in the slope of the cline.
What is a cline in biology?
Jump to navigation Jump to search. In biology, a cline, or 'ecocline', describes a series of connected populations in a species. These populations show a continuous gradient of traits and genetics. The term was coined by the English evolutionary biologist Julian Huxley in 1938. He defined a cline as a species whose members fall into a series ...
What are the forms of a species that show gradual phenotypic and/or genetic differences over a?
Clines consist of forms of a species that show gradual phenotypic and/or genetic differences over a geographical area.
What does "cline" mean in biology?
cline / klīn / • n. a continuum with an infinite number of gradations from one extreme to the other. ∎ Biol. a gradation in one or more characteristics within a species or other taxon, esp. between different populations.See also ecocline. DERIVATIVES: clin·al / ˈklīnl / adj.
What is a cline?
cline A gradual variation in the characteristics of a species or population over its geographical range. It occurs in response to varying environmental factors, such as soil type or climate.
What is the idea of a cline?
This is what the idea of a “cline” is about: Gradual genetic changes within a species that is stretched over a large area.
What term is used to shorten the biological terms and make a sensible thought that you can remind easily in easy going?
Mnemonics:- This is the term which is used to shorten the biological terms and make a sensible thought that you can remind easily in easy going language.
What are biological agents?
Biological agents are living things, or products of living things, that can cause illness and disease in humans. Biological agents include viruses, bacteria and fungi, as well as parasitic worms and some plants.
How do biological agents enter the body?
Biological agents enter the body when they are inhaled, eaten (ingested) or absorbed. Most biological agents are inhaled. Once inside the body, these infectious agents can multiply quickly and may be passed from one person to another. Some can survive outside the body for a quite a long time if they have the right breeding ground, such as water or food. Others die quickly without the protection of the body.
What do ecologists study?
To find the answers to these questions, ecologists must study and observe all forms of life and their ecosystems throughout our world. In addition to examining how ecosystems function, ecologists study what happens when ecosystems do not function normally. Changes in ecosystems can result from many different factors including diseases among ...
What is the term for a scientist who studies the relationships between organisms and their environments?
Noun. scientist who studies the relationships between organisms and their environments. ecology . Noun. branch of biology that studies the relationship between living organisms and their environment. ecosystem. Noun. community and interactions of living and nonliving things in an area. microorganism.
What is the study of the environment?
Ecology is the study of organisms and how they interact with the environment around them. An ecologist studies the relationship between living things and their habitats. In order to learn about the natural world, ecologists must study multiple aspects of life ranging from the moss that grows on rocks to the wolf population in Yellowstone National Park. In order to research the environment, scientists ask questions, such as: How do organisms interact with the living and nonliving factors around them? What do organisms need to survive and thrive in their current environments? To find the answers to these questions, ecologists must study and observe all forms of life and their ecosystems throughout our world.
When did ecology become popular?
Ecology first began gaining popularity in the 1960s, when environmental issues were rising to the forefront of public awareness.
What is a tiny living thing?
very tiny living thing. area of tall, mostly evergreen trees and a high amount of rainfall. The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.
Overview
In biology, a cline (from the Greek κλίνειν klinein, meaning "to lean") is a measurable gradient in a single character (or biological trait) of a species across its geographical range. First coined by Julian Huxley in 1938, the "character" of the cline referred to is usually genetic (e.g. allele frequency, blood type), or phenotypic (e.g. body size, skin pigmentation). Clines can show smooth, continuous gradation in a character, or they may show more abrupt changes in the trait from on…
Drivers and the evolution of clines
Clines are often cited to be the result of two opposing drivers: selection and gene flow (also known as migration). Selection causes adaptation to the local environment, resulting in different genotypes or phenotypes being favoured in different environments. This diversifying force is countered by gene flow, which has a homogenising effect on populations and prevents speciation through causing genetic admixture and blurring any distinct genetic boundaries.
Clinal structure and terminology
The steepness, or gradient, of a cline reflects the extent of the differentiation in the character across a geographic range. For example, a steep cline could indicate large variation in the colour of plumage between adjacent bird populations. It has been previously outlined that such steep clines may be the result of two previously allopatric populations with a large degree of differenc…
Types of clines
According to Huxley, clines can be classified into two categories; continuous clines and discontinuous stepped clines. These types of clines characterise the way that a genetic or phenotypic trait transforms from one end of its geographical range of the species to the other.
In continuous clines, all populations of the species are able to interbreed and t…
Clines and speciation
It was originally assumed that geographic isolation was a necessary precursor to speciation (allopatric speciation). The possibility that clines may be a precursor to speciation was therefore ignored, as they were assumed to be evidence of the fact that in contiguous populations gene flow was too strong a force of homogenisation, and selection too weak a force of differentiation, for …
Clinal maps
Clines can be portrayed graphically on maps using lines that show the transition in character state from one end of the geographic range to the other. Character states can however additionally be represented using isophenes, defined by Ernst Mayr as "lines of equal expression of a clinally varying character". In other words, areas on maps that demonstrate the same biological phenomenon or character will be connected by something that resembles a contour line. When …
Examples of clines
Although the term "cline" was first officially coined by Huxley in 1938, gradients and geographic variations in the character states of species have been observed for centuries. Indeed, some gradations have been considered so ubiquitous that they have been labelled ecological "rules". One commonly cited example of a gradient in morphology is Gloger's Rule, named after Constantin G…