what does biological variation mean

variation, in biology, any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences (genotypic variation) or by the effect of environmental factors on the expression of the genetic potentials (phenotypic variation).

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What are the types of variation in biology?

the following types of variation are distinguished: genetic variation (genotypic) and nongenetic variation (paratypic), individual and group variation, discontinuous (discrete) and continuous variation, qualitative and quantitative variation, independent variation of various characters and correlative variation, directed (determined, according to …

What is an example of variation in biology?

Genetic variation in a group of organisms enables some organisms to survive better than others in the environment in which they live. Organisms of even a small population can differ strikingly in terms of how well suited they are for life in a certain environment. An example would be moths of the same species with different color wings.

What is the definition of variation in biology?

variation, in biology, any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences (genotypic variation) or by the effect of environmental factors on the expression of the genetic potentials (phenotypic variation).

What is the scientific definition of variation?

variation, in biology, any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences (genotypic variation) or by the effect of environmental factors on the expression of the genetic potentials (phenotypic variation). Variation may be shown in physical appearance, metabolism, fertility, mode of reproduction, behaviour, learning ...

What is meant by biological variation?

Biological variation or variance can be defined as the appearance of differences in the magnitude of response among individuals in the same population given the same dose of a compound.

What is an example of biological variation?

Eye colour, body form, and disease resistance are genotypic variations. Individuals with multiple sets of chromosomes are called polyploid; many common plants have two or more times the normal number of chromosomes, and new species may arise by this type of variation.

Why is biological variation important?

Biological variation is essential to species survival because natural selection acts upon the phenotypic variation within a population: the more varied the population's genetic resources, the more likely that the population will persist into the future.

What causes biological variation?

Major causes of variation include mutations, gene flow, and sexual reproduction. DNA mutation causes genetic variation by altering the genes of individuals in a population. Gene flow leads to genetic variation as new individuals with different gene combinations migrate into a population.

What are the 4 types of variation in biology?

Variations mean the differences (morphological, physiological, cytological and behaviouristic) amongst the individuals of the same species and the offspring of the same parents.

What is a simple definition of variation?

1 : a change in form, position, or condition Our routine could use some variation. 2 : amount of change or difference Scientists record the variations in temperature. 3 : departure from what is usual to a group The poodle's offspring show no variation from the breed.

What is within subject biological variation?

Background: Within-subject biological variation data (CVI) are used to establish quality requirements for assays and allow calculation of the reference change value (RCV) for quantitative clinical laboratory tests.

What is biological variation in nursing?

Biological Variation These factors include race, body structure, genetic variations, nutritional preferences and psychological characteristics (Davidhizar, & Giger, 2008). Nursing examples include diseases related to specific ethnic groups as well as rural versus urban health.

What are types of variation?

More examplesContinuous variationDiscontinuous variationHeightBlood groupWeightHand used to write withArm spanEye colourHead circumference at birthAbility to roll tongue

What are some common human variations?

Common human variationsType of VariationExampleSexKlinefelter syndrome Turner syndrome Female MaleSkin ColorHuman skin color AlbinismEye ColorEye color Martin scaleHair ColorHuman hair color Hair coloring4 more rows

What is biological variation in nursing?

Biological Variation These factors include race, body structure, genetic variations, nutritional preferences and psychological characteristics (Davidhizar, & Giger, 2008). Nursing examples include diseases related to specific ethnic groups as well as rural versus urban health.

What is the most significant biological variation in terms of nursing care among different races?

Skin color is probably the most significant biological variation in terms of nursing care. Nursing care delivery is based on accurate client assessment, and the darker the client's skin, the more difficult it becomes to assess changes in color.

What is within subject biological variation?

Background: Within-subject biological variation data (CVI) are used to establish quality requirements for assays and allow calculation of the reference change value (RCV) for quantitative clinical laboratory tests.

What are some common human variations?

Common human variationsType of VariationExampleSexKlinefelter syndrome Turner syndrome Female MaleSkin ColorHuman skin color AlbinismEye ColorEye color Martin scaleHair ColorHuman hair color Hair coloring4 more rows

How to find total variation?

The total variation is the square root of the sum of the squares of the component variations, CVt = (CVa 2 + CVb 2) 1/2. To calculate the RCV, CVt is multiplied by 2 1/2 because there are two samples, and then by a factor, conventionally called Z, which is equal to the number of standard deviations appropriate for the probability selected.

Why are preanalytical variations called preanalytical variations?

These sources of variation, both in sample collection and in handling, are termed “preanalytical variation” by laboratory professionals because they occur before the analysis is performed.

Why do numerical test results vary?

Test results vary in individuals over time due to preanalytical variation, analytical imprecision and biological variation. The important question is whether changes seen in patients do infer clinical improvement or deterioration. To interpret serial results in an individual objectively, ...

How can preanalytical variation be minimized?

As already agreed, preanalytical variation can be minimized by adherence to SOP for sample collection and handling and with good and ongoing training. Thus, changes in serial results are significant only if they exceed the inherent analytical imprecision plus biological variation.

How does bias affect test results?

Analytical bias also affects test result interpretation when population-based reference values are used. Bias should be less than one-quarter of the group biological variation to allow the same reference values to be used in alternate sites.

Is within or between subject variation less?

For most analytes, the within-subject variation is much less than the between-subject variation [2]. This has very interesting consequences for clinical investigation that are detailed elsewhere [1].

Is a change in serial results significant?

The Clinical Biochemist explained that, since test results do vary because of preanalytical variation, analytical imprecision and biological variation, a change in an individual patient must exceed these sources of variation to be significant.

What are the two types of biological variation?

There are two types of biological variations: within-subject and between-subject. Within-subject variation is the random fluctuation around a homeostatic point. In individuals, the homeostatic points usually vary. The variation between individuals is called between-subject biological variation.

How to determine biological variation?

Within-subject and between-subject biological variations are determined by conducting a biological variation study. The first step of the study is to recruit study subjects of interest. The study subjects can be healthy or patients with stable diseases depending on the contexts of the study. The second step is to take serial samples from study subjects at regular intervals that are consistent with the intended use of the tests. Next, the samples are analyzed in duplicates, and statistical techniques such as analysis of variance (ANOVA) are used to determine the analytical, within-subject, and between-subject biological components of variations.

What is the RCV of significant change?

For total cholesterol, RCV of significant change is calculated to be 17.5%, using the analytical variation of 2.0% and within-subject variation of 6.0%. The within-subject variation of total cholesterol is taken from the book Biological Variation: From Principle to Practice by Callum G. Fraser. The actual change of total cholesterol was calculated to be 21.3%. The actual change was larger than the RCV of significant change, and therefore the change of total cholesterol level from 225 to 273 mg/dL was significant.

What is the RCV of a reference change?

Reference Change Value (RCV) will help us to understand whether the change of an individual’s serial result is statistically significant. RCV is determined by Z score, analytical variation (CV A), and within- subject variation (CVI), assuming that pre-analytical variation (CVP) is negligible. Z score is defined as a number of standard deviations that a result is from the mean. Z score of 1.96 indicates a probability of 95%, statistically significant. When Z score is 2.58, it indicates the change would have a probability of 99%, therefore statistically highly significant. Whether Z score of 1.96 or 2.58 should be used depends on the clinical contexts. In the rest of this lecture, Z score of 1.95 or RCV of 95% will be used.

What is the population based reference range?

Traditionally, population-based reference range is determined as 90% confidence intervals for the 95th percentile reference limits at the 2.5th and 97.5th percentiles. Population-based reference ranges are often used to interpret patients’ lab results.

Why is biological variation important?

Biological variation is an important concept for clinical chemists to understand, because it helps answer many questions that clinical chemists encounter on a daily basis. For example, it can be used to determine whether the changes that occur in an individual’s results are statistically significant or not.

Can you find biological variation in literature?

Therefore, by doing a literature search, we could find within-subject and between-subject biological variation values for most of the common analytes. However, the caveat of using the published biological variation values is that they are method- and study subject-dependent, and therefore, may not be universally applicable.

Why is biological variation important?

Biological variation is important for survival of individuals and species, and is the underpinning force behind evolution. The intricacies of human biology with its many layers of interconnecting networks and inbuilt redundancy evolved over many millions of years to maximize an individual's chance of survival.

What is normal biological variation?

The normal variability in the test species is called normal biological variation. The distribution of measurements typically follows a normal or Gaussian distribution. This distribution is described as a “bell-shaped” curve (as shown in Fig. 1 ), an essential underpinning of many statistical analyses. In essence, this is the background of “noise” against which backdrop observations are made. Mathematics can help clarify whether the results seen in an experiment are a result of biological “noise” or a treatment-related “signal.” Just as the experimenter cannot be sure that the treatment did have an effect, statistical analyses do not give a definite yes or no answer, rather a probability statement.

What is the goal set up of analytical variation?

The goal set-up is that variance due to analytical error should not exceed 20% of the variation ( Fraser, 1983 ). It can be shown that this is acceptable when CV analytical ≤1/2CV intra-individual or ≤1/2CV biological ( Fraser and Harris, 1989 ).

What is normal variability in the test species?

The normal variability in the test species (normal biological variation) provides a distribution of measurements that typically follow a normal or Gaussian distribution. This distribution is described as a bell-shaped curve (as shown in Figure 30.1 ), and is an essential underpinning of many statistical analyses. In essence, this distribution is the background of “noise” against which backdrop observations are made. Mathematics can help clarify whether the results seen in an experiment are a result of biological noise or a treatment-related signal. Just as the experimenter cannot be sure that the treatment did have an effect, statistical analyses does not give a definite yes or no answer, but rather renders a probability statement regarding the likelihood that the treatment is responsible for inducing the effect.

What is the x axis of a normal biological variability curve?

FIGURE 30.1. Normal biological variability – bell shaped curve. The x-axis reports the frequency of the observation; the y -axis reports the measurement. SD, standard deviation.

How does biological variation affect our lives?

Biological variation is central to all our lives. Diversity in our own species is recognized in a number of visible characteristics, such as height, and functional characteristics, such as biotransformation abilities. The latter source of variability has led to the developing field of pharmacogenomics. Unfortunately, biological diversity interferes with efforts to test treatment effects, even when the experiment is designed and controlled a priori. No matter how inbred study animals are, and consequently how alike their physiological responses are likely to be, there is always a range of response displayed in measurements made on these animals. This fact has been confirmed many times in monozygotic human twins, and more recently in cloned animals.

Why is diversity important in biology?

Within each species, diversity is essential for survival and finding a niche in which to develop. Without exploring the theory of evolution, diversity in our own species is recognized in a number of visible characteristics, such as height, and functional characteristics, such as biotransforming abilities. The latter source of variability has led to the developing field of pharmacogenomics. Unfortunately, biological diversity interferes with efforts to test treatment effects, even when the experiment is designed and controlled a priori. No matter how inbred study animals are, there is always a range of response displayed in measurements made on these animals.

What is the significance of biological variations?

To understand the significance of biological variations, it is essential to understand other key terms, such as health disparities, health care disparities, health inequities, and health inequalities . These terms have augmented significance when health care professionals attempt to render culturally competent care to diverse, multicultural groups of people.

What are cultural differences?

Cultural differences are evident in communication, spatial relationships and needs, social organizations (family, kinships, and tribes), time orientation, and ability or desire to control the environment. Less recognized and understood are the biological differences among people in various racial groups.

Why is genetics important?

Population genetics is extremely important because human beings tend to marry or mate with people primarily like themselves—that is, the same racial, ethnic, and cultural groups.

Why are there differences in skin color?

When working with people from diverse cultural backgrounds, the nurse should understand how different races evolved in relation to the environment. Biological differences noted in skin color may be attributable to the biological adjustments a person’s ancestors made in the environment in which they lived. For example, it has been scientifically postulated that the original skin color of humans was black ( ; ) and that white skin was the result of mutation and environmental pressures exerted on persons living in cold, cloudy northern Europe. The mutation is believed to have occurred because light skin was better able to synthesize vitamin D, particularly on cloudy days. It is believed that black skin became a neutral trait in climates where protection from the sun and heat of the tropics was not a factor ( ; ).

Why is data relative to all variables significant to people within a racial group important?

Data relative to all the variables significant to people within a racial group are essential for complete understanding of the people. Not only are no two persons alike, but also no two cultural or racial groups are alike, and all phenomena relative to both individuals and cultural or racial groups must be understood.

Where does DNA come from?

DNA itself resides in a core, or what is known as the nucleus, of each of the cells in the body. In fact, every human cell, with the one notable exception of mature red blood cells, which have no nucleus, has the same DNA. All somatic cells have 46 molecules of double-stranded DNA.

What is biological variation?

Biological variation is a significant factor in interpretation of clinical and diagnostic data used in toxicology. A single toxicity figure will not define the range of toxicity and effects in a given population. Because LD50 or other values are usually defined in very similar animals (e.g., laboratory rats and laboratory beagles), the laboratory toxicity figure does not reflect the biological variation and differences in toxicity that may occur in a diverse group of breeds within the canine or any other species. For animals of veterinary importance there is usually insufficient information on the variability of effects from low or moderate exposures. Furthermore, individual environmental and husbandry conditions vary widely and can affect the severity of response in any particular group of animals for a specific toxicant and dosage. Therefore, thorough clinical and environmental investigation and good laboratory diagnostic procedures are essential to toxicological evaluation in a suspected exposure.

How to ensure reliability of BV estimates?

To assure the reliability of BV estimates, several preanalytical factors should be controlled. Subject s should maintain their normal lifestyle and protected, as much as possible, from emotional and environmental changes during the time of sample collections. If samples are collected over multiple days, collection times should be within a narrow time range of the day. Sample collection should be performed by the same phlebotomist with the same tourniquet application time. Subjects should be allowed to rest for few minutes, and samples should be collected while subjects are in the same posture, for example, sitting or lying down.

How many subjects are used in BV assay?

More samples and subjects, if feasible, can be better but 4 samples from 10 subjects were used and seemed enough [8]. Typically, BV studies are conducted on healthy individuals who are not suffering from any disease or trivial conditions, for example, allergy or flu. Some [26–28] reported intrasubject BV in diseased subjects but, in such cases, disease should not be expected to change over the sampling time window.

What is the difference between CV and CV A?

Intersubject or within-group BV in terms of CV (CV G )= (CVT TG2 −CV A2) 1/2 where CV TG is the total intersubject CV, that is , CV calculated from assayed values, and CV A is the within-run analytical variability in terms of CV (assuming that all samples will be analyzed on a single run).

How does genetic variation occur?

Genetic variation occurs mainly through DNA mutation, gene flow (movement of genes from one population to another) and sexual reproduction. Since environments are unstable, populations that are genetically variable will be able to adapt to changing situations better than those that do not contain genetic variations.

What is biological evolution?

Regina Bailey. Updated October 27, 2019. Biological evolution is defined as any genetic change in a population that is inherited over several generations. These changes may be small or large, noticeable or not so noticeable. For an event to be considered an instance of evolution, changes have to occur on the genetic level ...

What Is Natural Selection?

Natural selection is the process by which biological evolutionary changes take place. Natural selection acts on populations and not individuals. It is based on the following concepts:

What is the term for a change in the genetics of a population?

A change on the genetic level of a population is defined as a small-scale change and is called microevolution. Biological evolution also includes the idea that all of life is connected and can be traced back to one common ancestor. This is called macroevolution.

Why is evolution controversial?

The controversy stems from the perception that biological evolution is at odds with religion concerning the need for a divine creator.

What is considered an instance of evolution?

For an event to be considered an instance of evolution, changes have to occur on the genetic level of a population and be passed on from one generation to the next. This means that the genes, or more specifically, the alleles in the population change and are passed on.

How does sexual reproduction affect the population?

Sexual reproduction makes it possible to assemble favorable gene combinations in a population or to remove unfavorable gene combinations from a population. Populations with more favorable genetic combinations will survive in their environment and reproduce more offspring than those with less favorable genetic combinations.

What is natural variability in a lab parameter?

The natural variability in a lab parameter due to physiologic differences among subjects and within the same subject over time.

How often are blood samples drawn for within day variability?

To study the within-day biological variability, blood samples were drawn every hour during 24 h using an intravenous cannula.

Why do biomarkers need to be validated across a large number of samples?

Due to innate biological variability, verified candidate biomarkers need to be validated across a large number of samples by developing targeted quantitation assays.

How much genetic variation is there between races?

Genetic studies demonstrate that about 85.4 percent of all the variation in the human species can be attributed to variation within populations and that there is only a 6.3 percent difference between “races,” with less than half of this value accounted for by known racial groupings (see Lewontin 1972; Barbujani, Magani, Minch, et al. 1997). In other words, there is much more genetic variation within local groups than there is among local groups or among races themselves. This genetic unity means, for instance, that any local group contains, on average, 85 percent of the genetic variation that exists in the entire human species. As a result, there is about 15 percent genetic variation between any two individuals. Therefore, a randomly selected white European, although ostensibly far removed from black Americans in phenotype, can easily be genetically closer to an African black than to another European white. As summarized by Jeffrey Long and Rick Kittles in a 2003 article, the patterns of genetic variation within and between groups are too intricate to be reduced to a single summary measure. In other words, identification of trait frequencies and statistical partitions of genetic variation do not provide accurate information to justify claims for the existence of “races.”

What is the biological concept of race?

Historically, the ancient Egyptians were the first to classify humans on the basis of skin color. In 13# BCE Egyptians classified humans into four races: “red” for Egyptians, “yellow” for people living to the east of Egypt, “white” for people living north of Africa, and “black” for Africans from the south of Egypt. The ancient Greeks, on the other hand, referred to all Africans as “Ethiopians.” A major tenet of the biological concept of race is that the traits that identify a given race are unchangeable and have been fixed since the beginning of humankind. Since the early twentieth century, however, an evolutionary approach led by anthropologists and human biologists has emerged that calls into question the validity of the biological concept of race.

Who wrote Human Genetic Diversity and the Nonexistence of Biological Races?

Long, Jeffrey C., and Rick A. Kittles. 2003. “Human Genetic Diversity and the Nonexistence of Biological Races.” Human Biology 75 (4): 449–471.

Who wrote the rate of mutation of human genes?

Haldane, John B. S. 1949. “The Rate of Mutation of Human Genes.” Proceedings of the Eighth International Congress of Genetics: 267–273.

Is cultural environment a measure of IQ?

It is evident that cultural environment is an important contributor to any measures of IQ. This inference can be illustrated by several examples. First, consider two hypothetical groups of eight-year-old children: one from a middle class U.S. school and one from a poor rural area in Guatemala. These children are asked the following question: “Suppose you have five eggs and you drop two, how many eggs do you have?”

Who is the author of Genetics of the Evolutionary Process?

Dobzhansky, Theodosius. 1970. Genetics of the Evolutionary Process. New York: Columbia University Press.

Is IQ genetically determined?

Second, there is no evidence that IQ is genetically determined. It is true that about 60 percent of the variability in IQ is inherited within family lines, but the fact that it is inherited does not mean that it is genetically determined. Discrete traits such as blood type that do not change through the life cycle are genetically determined and, therefore, have a high heritability, but continuous traits such as height, weight, or IQ are highly subject to environmental influence. Heritability is computed as the fraction of phenotypic variability due to genetic differences divided by total variability. It is expressed as h 2 = G/P = G/ (G + E), where G is variability in genotype, E is variability in environment, and P is variability in phenotype. Depending upon whether the environmental variance (E) is large or small, the phenotypic variance (P) can be either large or small, and the heritability (h 2) can be either large or small. Measures of heritability, especially of continuous traits such as intelligence, indicate the joint influence of genetic and environmental factors. Twin and family studies have shown that shared environmental factors have an important effect on educational attainment (see Silventoinen et al. 2004). Shared environmental factors such as education have a greater impact on intelligence during childhood than in adulthood. In other words, heritability of intelligence (unlike genetic determination) can be very different in different populations, depending upon the environmental condition in which each population develops. Therefore, a low IQ score reflects the effects of poor education during childhood and negative environmental conditions.

What does biological mean in medical terms?

Medical Definition of biological. 1 : of or relating to biology or to life and living processes. 2 : used in or produced by applied biology. 3 : related by direct genetic relationship rather than by adoption or marriage an adoptee who searched for years for her biological parents. Other Words from biological.

What does "biologic" mean?

Definition of biological. 1 : of or relating to biology or to life and living processes. 2 : used in or produced by applied biology. 3 : connected by direct genetic relationship rather than by adoption or marriage her biological father.

Do you have to have a biological relationship to be married in 2021?

— Ashley Andreou, Scientific American, 7 June 2021 However, under the Immigration and Nationality Act, there is no requirement for a biological relationship for married parents, according to Immigration Equality. — Caitlin O'kane, CBS News, 20 May 2021 Dockside values were down across the board due to a mix of biological factors and COVID disruptions. — Anchorage Daily News, 10 May 2021 Finally, certain biological factors increase the chance that a child will develop autism. — Bayliss Wagner, USA TODAY, 19 Apr. 2021 Throughout the pandemic, men worldwide have been far more likely to die from COVID-19 — because of a mix of biological and behavioral factors — but also less likely to have been vaccinated against the disease. — Los Angeles Times, 14 Apr. 2021 Emma had been born when her biological mother, who used drugs, was in jail. — Rachel Aviv, The New Yorker, 11 Oct. 2021

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How Is It Used in Everyday Practice?

• The medical, nursing and other professional staff on the ward round all understood the concept that variation in test results in individuals was due, not only to improvement or deterioration, but also to preanalytical variation, analytical imprecision and within-subject biological variation. However, they wondered why clinical biochemists had spent...

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Is A Change in Serial Results significant?

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