The hundreds of species of Drosophila in Hawaii exhibit different mating rituals. This isolating mechanism is

Question

A.  prezygotic and behavioral.
B.  prezygotic and temporal.
C.  prezygotic and geographical.
D.  postzygotic and mechanical.
E.  prezygotic and ecological.

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?

  Gather Content
· What do you already know about reproductive isolation mechanisms?

  Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
 
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?

Answer 1

A.  prezygotic and behavioral.

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses reproductive isolation mechanisms.
· 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 reproductive isolation mechanisms?
        o Populations are considered to be different species when the members are reproductively isolated from each other.
        o Reproductive isolating mechanisms prevent genetic exchange between species. Some prevent the formation of zygotes – prezygotic isolating mechanisms. Others prevent the proper functioning of zygotes after they form – postzygotic isolating mechanisms.
        o Prezygotic isolating mechanisms include ecological isolation, behavioral isolation, temporal isolation, mechanical isolation, and prevention of gamete fusion.
        o Ecological isolation happens when two species occur in the same area, but use different portions of the environment and thus do not hybridize.
        o Behavioral isolation is when related species differ in their courtship rituals, keeping these species distinct.
        o Temporal isolation is when species reproduce in different seasons.
        o Mechanical isolation is when the morphology of two species prevents mating.
        o Sometimes gametes cannot fuse properly even when they meet.
        o Postzygotic isolation occurs when hybrids between species are either inviable (poor at surviving) or infertile (unable to reproduce themselves).

  Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o In this example of the Hawaiian Drosophila species, they do not interbreed because they have different courtship rituals. This is a behavioral isolating mechanism.
        o Without interbreeding, the sperm and egg never meet at all, so a zygote never has a chance to form. Thus this is a prezygotic isolating mechanism.
 
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 when two species do not interbreed because of incompatible courtship rituals, this is a behavioral, prezygotic isolating mechanism?