What is the first thing that must happen in order for speciation to occur?

• A. A catastrophic event must cause geographic separation of two populations.
• B. A hybrid zone must be established.
• C. The populations must become reproductively isolated.
• D. One of the populations must become polyploid.
• E. Gene flow between populations must be interrupted.

Answer: (E)

Verified step by step guidance

1. Understand the concept of speciation: Speciation is the process by which populations evolve to become distinct species. It often involves the interruption of gene flow between populations.
2. Identify the role of gene flow: Gene flow is the transfer of genetic material between populations. For speciation to occur, gene flow must be interrupted, allowing populations to diverge genetically.
3. Consider mechanisms of gene flow interruption: This can happen through geographic isolation, where physical barriers prevent populations from interbreeding, or through reproductive isolation, where genetic or behavioral differences prevent successful mating.
4. Evaluate the options given: Analyze each option to determine which one directly leads to the interruption of gene flow. Geographic separation and reproductive isolation are common mechanisms that can lead to speciation.
5. Conclude with the correct condition for speciation: The key requirement for speciation is the interruption of gene flow between populations, allowing them to evolve independently.