Choose the best cause and effect sequence for the process of speciation by natural selection.

Question

A.  Variation --> Selection --> Reproductive Isolation --> Mutation --> Speciation
B.  Mutation --> Variation --> Selection --> Reproductive Isolation --> Speciation
C.  Speciation --> Reproductive Isolation --> Selection --> Mutation --> Variation
D.  Variation --> Reproductive Isolation --> Speciation --> Mutation --> Selection
E.  Selection --> Speciation --> Reproductive Isolation --> Variation --> Mutation

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 natural selection and speciation?
 
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

B.  Mutation --> Variation --> Selection --> Reproductive Isolation --> Speciation

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses natural selection and speciation.
· What type of thinking is required?
        o This question is asking you to analyze the information given, using logic, to dissect the problem and determine the answer.
 
Gather Content
· What do you already know about natural selection and speciation?
        o Natural selection often plays a role in speciation.
        o As populations of a species adapt to different circumstances, they likely accumulate many differences that may lead to reproductive isolation. For example, if one population of flies adapts to wet habitats and another to dry areas, then natural selection will favor a variety of corresponding differences in physiological and sensory traits. These differences may produce ecological and behavioral isolation and may cause any hybrids the two populations produce to be poorly adapted to either habitat. Selection might also act directly on mating behavior.
 
Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o The first step in evolution is the random occurrence of a mutation. The mutation in DNA produces variation in phenotype, which is what selection can act upon.
        o The new phenotype may lead to reproductive isolation, by a variety of mechanisms. And reproductive isolation is the necessary prerequisite for speciation.
        o The full sequence is: Mutation --> Variation --> Selection --> Reproductive Isolation --> Speciation.
 
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 analyze the information given, using logic, to dissect the problem and determine the answer.
        o Did you recognize that mutations are the source of variation that selection acts upon?
        o Did you recognize that reproductive isolation leads to speciation?