Florida Biology EOC Practice Test 2025 - Free Biology End-of-Course Practice Questions and Study Guide

Genetic drift refers to changes in allele frequencies within a population due to random sampling effects, particularly in small populations. This concept emphasizes how random events, such as which individuals happen to reproduce, can lead to significant and unpredictable changes in the genetic makeup of a population over time.

Unlike natural selection, which involves adaptive changes driven by environmental pressures, genetic drift occurs independently of any benefits to survival or reproduction. It can lead to certain alleles becoming more common or entirely lost, regardless of their advantage or disadvantage. This randomness is akin to a coin toss; sometimes, chance will favor one allele over another simply due to the number of individuals reproducing.

The other options, while related to aspects of evolution and genetics, specifically do not encapsulate the core definition of genetic drift:

- The idea of evolution through adaptation focuses on the process of natural selection rather than random changes in allele frequencies.

- Mutation deals with changes in the DNA sequence itself over generations, which pertain to new traits arising rather than random shifts in existing allele frequencies.

- The introduction of new alleles from immigration describes gene flow, which involves alleles moving in and out of populations rather than changes due to random sampling effects within a stable population.

Thus, describing genetic drift as a