True or False
Genetic drift is a change in allele frequencies in a population from generation to generation that occurs due to chance events. Although genetic drift happens in populations of all sizes, its effects tend to be stronger in small populations.
The correct answer and explanation is:
True
Genetic drift is a mechanism of evolution that results in random changes in allele frequencies from one generation to the next due to chance events. Unlike natural selection, which is driven by adaptive advantages, genetic drift occurs randomly and can have significant effects on the genetic makeup of populations, especially small populations.
Explanation
Genetic drift occurs when allele frequencies fluctuate due to random sampling in reproduction. Each generation, only a subset of alleles from the parental population gets passed on, and this process can lead to some alleles becoming more common while others disappear entirely. This randomness can lead to significant genetic changes over time.
Why Genetic Drift is More Pronounced in Small Populations
- Reduced Genetic Variation
In smaller populations, fewer individuals contribute to the next generation, meaning that allele frequencies are more likely to change due to chance alone. If an allele is lost due to random deaths or reproductive failures, it may not be replaced. - Fixation and Loss of Alleles
Over time, genetic drift can lead to the fixation (100% presence) or loss (0% presence) of certain alleles. In small populations, this process happens more rapidly because there are fewer individuals to buffer against random fluctuations. - Bottleneck Effect
A population bottleneck occurs when a large portion of a population is suddenly wiped out due to an event like a natural disaster. The surviving individuals may not represent the original population’s genetic diversity, leading to significant allele frequency shifts. - Founder Effect
When a small group of individuals colonizes a new area, the new population’s gene pool is limited to the genetic variation of its founders. This can lead to significant genetic divergence from the original population due to drift.
Overall, genetic drift is an essential evolutionary force, particularly in small populations, and can lead to drastic genetic changes over time.
Here is the visual representation of genetic drift in a small population. The image illustrates how allele frequencies change over generations due to chance, with some genetic variations disappearing while others become dominant. Let me know if you need any modifications!
