Indicate the scenario(s) that could directly result in sympatric speciation. Check all that apply.A) Two sunflower species cross to form a healthy hybrid individual with equal copies of chromosomes from each parental species.B) A new river channel divides a population of beetles into two populations.C) A large fence blocks the intermingling of two populations of a species.D) A subset of flies within a larger population colonizes a new host plant.

Question

What will be an ideal response?

Answer 1

A, D

Clarify Question
• What is the key concept addressed by the question?
        o This question addresses sympatric speciation.
• What type of thinking is required?
        o This question is asking you to take what you already know and apply it to this unfamiliar situation.

Gather Content
• What do you already know about sympatric and allopatric speciation?
        o A population can diverge into two species because the population has been separated geographically: this is allopatric speciation.
        o Or, the population can diverge into separate species even when the populations are not separated: sympatric speciation.

Choose Answer
• Given what you now know, what information and/or problem-solving approach is most likely to produce the correct answer?
        o Sympatric speciation can only occur when two populations are reproductively isolated but not geographically isolated.
        o The two examples here of geographically overlapping populations are the hybridizing sunflower species and the flies that prefer a new host plant.

Reflect on Process
• Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o The question required you to take what you already know and apply it to this unfamiliar situation.
        o Did you recognize that sympatric speciation occurs when two populations that overlap geographically are reproductively isolated?