Mendelian population is a group of individuals who reproduce among themselves and share a common gene pool.
Sewall Wright in his 1930 paper - evolution in mendelian population - show how the population evolves. Synthetic theory further elaborated it as
Mutation. Changing gene frequencies over time create different populations from original
Migration. Create geographical isolation and might change gene frequency. New population evolves over time
Selection pressure due to nature leads to survival of fittest and change in gene pool.
Inbreeding increases homeo zygosity and keeps gene pool slow to change.
In humans, mendelian population created due to geography, religion, economic features. San 1996. Also influenced by kinship marriage patterns and ancestry. Sinnott 1961. Theoretically humans can made with others around the world but don't.
Hardy weinberg equation helps us study the the changes and evolution of mendelian populations.
Chandrasekar 1993. kamma population of Andhra Pradesh used to be mentally but in the last few decades uncle niece marriages have declined and it is becoming diverse.