How can reducing gene flow between two populations promote speciation?

• A. It guarantees that both populations remain genetically identical because no new alleles can arise without migration.
• B. It immediately creates postzygotic isolation by causing all hybrids to be sterile in the next generation.
• C. It allows populations to diverge genetically through mutation, natural selection, and genetic drift, which can lead to reproductive isolation.
• D. It increases the frequency of interbreeding between populations, preventing genetic differences from accumulating.

Answer: (C)

Verified step by step guidance

1. Understand the concept of gene flow: Gene flow is the transfer of genetic material between populations through migration and interbreeding, which tends to homogenize genetic differences.
2. Recognize that reducing gene flow limits the exchange of alleles between populations, allowing each population to accumulate unique genetic changes independently.
3. Identify the evolutionary mechanisms that act on isolated populations: mutation introduces new genetic variants, natural selection favors beneficial traits in each environment, and genetic drift causes random changes in allele frequencies.
4. Explain how these independent genetic changes can lead to reproductive isolation, meaning individuals from the two populations can no longer successfully interbreed to produce fertile offspring.
5. Conclude that reduced gene flow promotes speciation by enabling populations to diverge genetically and develop barriers to reproduction over time.