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Example Question #42 : Population Genetics
Which of the following is an example of gene flow?
Migration
Neither migration nor horizontal gene transfer
Horizontal gene transfer
Both migration and horizontal gene transfer
Both migration and horizontal gene transfer
Gene flow is a mechanism of evolution in which genes are transferred between populations. Two examples of gene flow are migration and horizontal gene transfer. In the case of migration, the movement of individuals into or out of a population also results in a transfer of alleles. Horizontal gene transfer (common in bacteria) is the transfer of genes through means other than reproduction (i.e. plasmid exchange).
Example Question #43 : Population Genetics
Evolution that occurs within a population due to the production of a finite number of zygotes from a given gene pool is referred to as which of these?
The Fonder Effect
Natural selection
Inbreeding depression
Loss of heterozygosity
Genetic drift
Genetic drift
Genetic drift is due to the production of a finite number of zygotes within a population. This causes allele frequencies to change from one generation to the next. Genetic drift can result in the reduction of the fitness of individuals within a population if the alleles passed on are deleterious.
Example Question #44 : Population Genetics
When a population is reduced for a short period of time, and only rare alleles are lost, this is referred to as which of these?
Bottlenecking
The Founder Effect
Divergence
Genetic drift
Natural selection
Bottlenecking
When a population is reduced for a short period of time, only the rarest alleles are usually lost, as is seen in bottlenecking. In order for a significant change in allelic frequency to be seen, the population must become significantly small, and it must stay small for a significant amount of time. The latter is referred to as the Founder Effect.
Example Question #231 : Evolution And Genetics
A population of geese migrates from Canada to Florida every winter. Individuals from the Canadian population sometimes breed with native Floridian geese. What is this an example of?
A prezygotic barrier
Sympatric speciation
Gene flow
Genetic drift
Gene flow
This is an example of gene flow, because a small number of individuals from one population are passing some genes on to those in another population. Genetic drift occurs within a single population, so it does not apply here. This is not an example of speciation. There can't be a prezygotic barrier present if the geese are able to successfully mate.
Example Question #241 : Evolution And Genetics
For natural selection to occur, which of the following must be true of a population?
Must be capable of sexual reproduction
Having many populations in one area
The population must be isolated
Food is not available
Phenotypic variations must be based on genetic variations
Phenotypic variations must be based on genetic variations
Example Question #1821 : Ap Biology
Which type of isolation between populations is due to barriers related to time, such as differences in mating periods or differences in the time of day that individuals are most active.
Geographic isolation
Temporal isolation
Two of these
Reproductive isolation
Behavioral isolation
Temporal isolation
Temporal isolation is between populations due to barriers related to time, such as differences in mating periods or differences in the time of day that individuals are most active. Geographic isolation between populations is due to physical barriers, not time. It wouldn't be both of them because only temporal isolation deals with time, versus geographic isolation is based on the physical barrier between populations such as mountains, rivers, or, for example, insects living on different trees in the jungle. Reproductive isolation is the inability to interbreed between species for various reasons like sterile offspring, physical incompatibility, or different mating rituals.
Example Question #1822 : Ap Biology
Which of the following is an example of genetic drift?
All of these are examples of genetic drift.
A massive storm randomly kills many individuals in a population, changing the frequency of alleles in that population.
An organism is born with traits not attributed to the alleles of its parents, but a brand new allele.
An allele increases in frequency due to the increase in fitness it provides the organism.
Individuals from one population move and mate with members of a different population.
A massive storm randomly kills many individuals in a population, changing the frequency of alleles in that population.
Genetic drift occurs when the frequency of alleles in a population change by random chance. Change in allele frequency based on biological fitness is natural selection, not genetic drift. The change in allele frequency due to members moving from one population to another describes migration. A brand new allele that did not exist in the parents is the result of mutation.
Example Question #241 : Evolution And Genetics
A population of wolves is living in an area when a tornado strikes and kills most of the wolves. The population of the wolves has been greatly reduced. Which of the following best describes the impact of the disaster on the genetic makeup of the population of wolves?
Founder effect
Hardy-Weinberg principle
Gene flow
Cannot be determined from the information
Bottleneck effect
Bottleneck effect
The Bottleneck effect happens when an event occurs that drastically reduces the population of a species. The remaining individuals most likely do not represent the genetics of the population before the catastrophic event, since it becomes a much smaller sample size.
Example Question #242 : Evolution And Genetics
There was once a population on planet M311, called the Freg, who lived on a planet not unlike Earth. At the height of the Fregs technology and evolution, a collection of asteroids bombarded the planet and the devastation was so great that the planet was split in two, as was the Freg population. Much of the Freg population died, but many still survived on both pieces of M311.
The asteroid was an enormous catastrophe that drastically reduced the Freg population. As a result, their gene pool will be significantly smaller. What is this phenomenon called?
The Dinosaur Hypothesis
Radical Genetecism
The Darwin Conundrum
The Bottleneck Effect
The Extinction Example
The Bottleneck Effect
The bottleneck effect is the correct answer here. The effect is defined as a sharp reduction in a populations size due to an environmental effect. In this scenario, the asteroids were the environmental effect and it caused the Freg population to decrease significantly. Also, none of the other answers are real theories.
Example Question #51 : Population Genetics
Which of the following is true of genetic drift?
Genetic drift involves the random change of allele frequencies in a population
None of these statements are true
Genetic drift helps reduce the frequency of harmful alleles in a population
Genetic drift only occurs in populations at Hardy-Weinberg equilibrium
The effects of genetic drift are negligible in smaller populations
Genetic drift involves the random change of allele frequencies in a population
Genetic drift is a direct result of independent assortment. Since genes are not inherited by any organized mechanism, there are random fluctuations during which certain alleles experience an increase in frequency over others.
Genetic drift results in random changes in allele frequency; these changes are not a cause of genetic drift. In smaller populations and extreme cases, random changes can result in the loss of an allele entirely within the population. The results of genetic drift are more prominent in smaller populations due to their already reduced gene pool. Since genetic drift is random, both beneficial and harmful alleles can be promoted or eliminated.
Genetic drift cannot increase genetic diversity. The only way to increase genetic diversity is by the introduction of new traits and alleles. Genetic drift can reduce genetic diversity by eliminating alleles from a population, but is incapable of creating new traits. This can only be done through mutation.
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