Question

chapter quiz: processes of evolution
total points: --/100
what are characteristics of sympatric speciation? select all that apply.
reproductive isolation unnecessary to end gene flow
presence of a physical barrier
absence of a physical barrier
reproductive isolation necessary to end gene flow

Explanation:

Define sympatric speciation

Sympatric speciation is the formation of new species from a single ancestral species while inhabiting the same geographic region. Unlike allopatric speciation, there is no geographic separation or physical barrier isolating the populations.

Analyze the role of physical barriers

Because the populations share the same geographic area, the "Absence of a physical barrier" is a defining characteristic of sympatric speciation. Conversely, the "Presence of a physical barrier" is characteristic of allopatric speciation.

Analyze the role of reproductive isolation

For speciation to occur, populations must diverge genetically until they can no longer interbreed. This means Reproductive Isolation is absolutely necessary to halt Gene Flow between the diverging groups, even when they live in the same area. Without reproductive isolation, continuous gene flow would prevent divergence.

Evaluate the given options

• "Reproductive isolation unnecessary to end gene flow": Incorrect. Reproductive isolation is required to stop gene flow.
• "Presence of a physical barrier": Incorrect. This describes allopatric speciation.
• "Absence of a physical barrier": Correct. Sympatric speciation occurs in the same geographic area.
• "Reproductive isolation necessary to end gene flow": Correct. Halting gene flow via reproductive barriers is essential for speciation.

Answer:

• Reproductive isolation unnecessary to end gene flow
• Presence of a physical barrier
• Absence of a physical barrier (Correct answer)
• Reproductive isolation necessary to end gene flow (Correct answer)