What kinds of evolutionary trends are represented by each of the two diagrams below? The x-axis represents an arbitrary scale for a trait value,in this case eyespot diameter on a butterfly's wing.
A)A = active trend; B = passive trend
B)A and B = active trend
C)A = passive trend; B = active trend
D)A and B = passive trend

Question

What kinds of evolutionary trends are represented by each of the two diagrams below? The x-axis represents an arbitrary scale for a trait value,in this case eyespot diameter on a butterfly's wing. 
A)A = active trend; B = passive trend 
B)A and B = active trend 
C)A = passive trend; B = active trend 
D)A and B = passive trend

Quizplus · Accepted Answer

In diagram A, the trend appears to be a passive trend where there is no directional selection pushing the trait in a certain direction. In diagram B, there appears to be an active trend where there is directional selection pushing the trait towards smaller eyespot sizes. Therefore, A represents a passive trend and B represents an active trend.

What Kinds of Evolutionary Trends Are Represented by Each of the Two