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Evolution is the change in allele frequency over time in a population of organisms. By mutation, genetic drift, gene flow and natural selection.

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What describes genetic drift?

random changes in allele frequency (apex) [Correct]


What happens when Rare allele is in a small population?

The smaller the population the greater the frequency the allele will increase. When the Old Order Amish came to America in 1744 it was a husband and wife. One of them was a carrier for a recessive genetic mutation. As time went on and inbreeding occured because of the small population more and more children were born with the genetic disorder.


What circumstances that genetic drift occur?

Genetic drift is the fluctuation of allele frequencies in a population due to chance. Chance plays a role in several ways. Copies of alleles can be lost because they never make it into gametes. Another possibility is, if the allele copy makes into a sperm, that sperm isn't the one that fertilizes an egg. Maybe the organism that carries copies of the allele in its gametes fails to find a mate, or is killed before reproducing. These kinds of events can influence the frequency of that alelle in a population, and occurs regardless of any selection for or against that allele. Obviously, the smaller the population, the larger the effect drift has on the allele frequency. For example, consider a population of four organisms. Each has two copies of a particular gene (one on each chromosome). Now, consider a mutation that creates a new allele for that gene, and that it appears on one chromosome of one individual. That allele will have a frequency of 1/8 in that population, so if it is lost, the frequency change will be 1/8. Now imagine a population of eight individuals; the frequency of the new allele would be 1/16, so if it was lost, the change in frequency would be less than in a population of four. It should therefore be easy to see that the effect of genetic drift on allelic frequency change is dramatically less in very large populations. In fact, in an essentially infinite population, genetic drift would have a negligible effect on the frequency of an allele. Another factor that can influence allele frequency, and which is a part of genetic drift is non-random mating. If an organism does not have an equal probability of mating with any other organism in a population, then some alleles will increase or decrease in frequency simply due to that. For instance, if a population exists over a large geographic range, individuals that live closer to each other have a greater probability of mating than those who live far apart. Species who employ reproductive strategies such as leks,where males gather together and compete for the privilege of mating with females are also examples of non-random mating. Lekking increases the effects of drift because it reduces what biologists call the effective population size, or the number of breeding adults. For the above reasons, when population geneticists want to study factors that affect the frequency of an allele (such as natural selection), and they want to minimize the effects of drift, they model populations that are very large (essentially infinite) and assume random mating.


Which of the following statements is accurate about evolution?

Since there are no following statements could it be........? Evolution is the change in allele frequency over time in a population of organisms.


What is non random association of alleles at two or more loci?

Allele association. Linkage disequilibrium- measure of correlation in allele frequencies between two loci. Non-random association indicated linkage disequilibrium while random does not.

Related Questions

The change in allele frequency?

Random change in allele frequency is called genetic drift.


What is the Random change in a populations allele frequency is known?

Genetic drift is the random change in allele frequencies in a population. It is caused by chance events and has more pronounced effects in small populations where genetic diversity is lower. Over time, genetic drift can lead to the loss of certain alleles or fixation of others in a population.


What are the changes of allele frequency in a small population that is due to random chance and don't follow the laws of probability?

Random changes in allele frequency are due to genetic drift.


What is genetic drift and how does it affect the evolution of a species?

All events that result in changes in allele frequencies in populations contribute to evolution. Genetic drift likewise. Genetic drift is no different from all other reproductive variation, save that the term refers to changes that are more or less neutral.


What happens when a population is in hardy weinberg equillibrium?

In Hardy-Weinberg equilibrium, allele frequencies in a population remain constant from generation to generation. This means that the population is not evolving. Factors such as no mutation, no gene flow, random mating, large population size, and no natural selection contribute to Hardy-Weinberg equilibrium.


Why do allele frequencys in a gene pool change in gentetic drift?

Let us take a random example, which is genetic drift. A small population of beetles are on a small island. Some few are green, recessive, (gg) and most are brown, dominant (Bg and BB). So you see that the majority of the population are brown, which also happens to be the adaptively favored color. Bird populations go through a boom on this island and almost all the green beetles are eaten. The allele frequency will change through this random process of genetic drift.


What is random change in allele frequencies in small population?

Random changes in allele frequencies in small populations are known as genetic drift. Genetic drift occurs due to chance events, leading to unpredictable fluctuations in the frequency of alleles within a population. In small populations, genetic drift can have a significant impact and may result in certain alleles becoming more or less common or even being lost altogether over time.


Which best describes genetic drift?

random changes in allele frequency - apex


What causes an allele frequency to go up in one generation and back down in the next generation?

There are three basic reasons: 1. Natural Selection-- thr environment may have favored the allele in previous generations, but now disfavors it. 2. Genetic Drift-- in every finite population, the frequency of an allele will fluctuate due to chance. For example, the vast majority of sperm fail to fertlize any egg, so allels can be lost this way due to chance. Individuals carrying a copy or copies of an allele may die young due to random accidents, or may never find a mate. These basic chance events cause the frequencies of alleles to fluctuate, and the degree of frequency change depends upon the population size. The greater the population size, the smaller the change in frequency. 3. A combination of both.


Generation-to-generation change in allele frequencies in a population is?

The term used to describe the generation-to-generation change in allele frequencies of a population is simply evolution. Simple answer for a complicated-looking question. ;) Hope this helps.


How does genetic drift lead to a change in a populations gene pool?

Genetic drift reduces variation in a population through allele loss, there are 2 situations of GD: a) Bottleneck effect: number of individuals is reduced significantly by a random event b) Founder effect: few individuals are separated and establish their own population both situations result in different allele frequency representations in new populations from their previous population`s


What factors change the allele frequency of a population?

Factors that can change the allele frequency of a population include natural selection, genetic drift, gene flow, mutations, and non-random mating. Natural selection favors certain alleles, genetic drift causes random changes, gene flow introduces new alleles, mutations create new variation, and non-random mating can lead to specific alleles being passed on more frequently.