Final answer:
Mutation and gene flow are evolutionary forces that can introduce new genetic variation into a population. Mutation causes changes in the DNA that can produce novel alleles, while gene flow involves the transfer of alleles between populations through interbreeding. Natural selection and genetic drift do not create new genetic variation but can influence existing allele frequencies.
Step-by-step explanation:
The evolutionary forces that can introduce new genetic variation into a population are mutation and gene flow. A mutation is a change in the DNA sequence that can generate new alleles and therefore new genetic variation. Mutations can be results of errors during DNA replication or caused by environmental factors.
Gene flow, also known as gene migration, occurs when breeding between two populations transfers new genetic variation from one population to the other. This can happen when individuals move between populations, interbreed, and introduce new alleles to the gene pool. While natural selection and genetic drift do not create new genetic variations, they do alter allele frequencies within a population. It is important to note that natural selection typically eliminates deleterious alleles while favoring beneficial ones, hence it often reduces genetic diversity over time.
Genetic drift is a random process that can lead to changes in the population's allele frequencies, particularly in small populations or after bottleneck events. However, it is not a mechanism that introduces new genetic variation but rather influences it by chance events.