Answer:
Definition:
Biological evolution is the process through which the characteristics of organisms change over successive generations, by means of genetic variation and natural selection. It is most commonly defined as "changes in gene frequencies in populations."
A small change in genes could result in a mass epidemic. Such as the colinistists bringing yellow fever over to America.
Step-by-step explanation:
Biological evolution refers to the cumulative changes that occur in a population over time. These changes are produced at the genetic level as organisms' genes mutate and/or recombine in different ways during reproduction and are passed on to future generations.