How does genetic drift occur?
Genetic drift takes place when the occurrence of variant forms of a gene, called alleles, increases and decreases by chance over time. These variations in the presence of alleles are measured as changes in allele frequencies. Both possibilities decrease the genetic diversity of a population.
Does genetic drift demonstrate natural selection?
Genetic drift affects the genetic makeup of the population but, unlike natural selection, through an entirely random process. So although genetic drift is a mechanism of evolution, it doesn’t work to produce adaptations.
What is the difference between genetic drift and natural selection?
The key distinction is that in genetic drift allele frequencies change by chance, whereas in natural selection allele frequencies change by differential reproductive success. Natural selection is the process by which these adaptive traits become more common in a population.
What are three effects of natural selection?
Natural selection can cause microevolution, or a change in allele frequencies over time, with fitness-increasing alleles becoming more common in the population over generations. Fitness is a measure of relative reproductive success.
How important is genetic drift?
The consequences of genetic drift are numerous. It leads to random changes in allele frequencies. Drift increases the amount of genetic differentiation among populations if no gene flow occurs among them. Genetic drift also has two significant longer-term evolutionary consequences.
How does natural selection lead to evolution?
Natural selection is a process where organisms that are better adapted to an environment will survive and reproduce. This means that the advantageous alleles of this variant organism are passed on to offspring. Over many generations, the process of natural selection leads to evolution occurring.
What are the stages of natural selection?
Natural selection is a simple mechanism that causes populations of living things to change over time. In fact, it is so simple that it can be broken down into five basic steps, abbreviated here as VISTA: Variation, Inheritance, Selection, Time and Adaptation.