Explain how genetic drift affects populations

Genetic drift decreases the genetic diversity within a specie's population. Genetic drift is a change in the allele frequencies due entirely to random chance and probability and is more likely to affect smaller populations and groups than larger ones. Genetic drift can also play a role in the development of a new species.

Cite my info:

https://www.nature.com/scitable/topicpage/the-genetic-variation-in-a-population-is-6526354/

https://socratic.org/questions/how-does-genetic-drift-affect-the-diversity-of-organisms-in-a-population