Question 4
A student is investigating three organisms to determine patterns of common ancestry. The image shows the similarities in DNA of Organisms X, Y, and Z.
Three segments of D-N-A are labeled X, Y, and Z. Segment X shares six common D-N-A strands with segment Y. Segment X shares two common D-N-A strands with segment Z. Segments Y and Z do not share any common D-N-A strands.
The student wants to create a model to represent the relationships of the three organisms. Which cladogram should the student create?
a
A cladogram has three branches. The first branch is X, the second branch is Y, and the third branch is Z.
This cladogram does not show that organism X and organism Y are more closely related based on the similarities in their DNA.
b
A cladogram has one branch with three branches coming off of it in the order: Y, X, then Z.
This cladogram shows all of the organisms being closely related.
c
A cladogram has two branches. The first branch is Z. The second branch is X. Y branches off of X.
This cladogram correctly shows that the three organisms share some DNA, but that X and Y are more closely related based on the similarities in their DNA.
d
A cladogram has two branches. The first branch is X. Z branches off of X. The second branch is Y.
This cladogram incorrectly shows organism X and organism Z being more closely related.