Question 3
A scientist is performing an investigation using biochemistry to show the evolutionary relationship between an unknown species and four known species. She compares the DNA of the same protein found in all five species.
Her data is shown in the table.
Species Sequence
unknown ACT GCA CCC
species I ACA GCA CCG
species II ACT GGT GGA
species III ACA GCA GGG
species IV ACT GCA CCG
The scientist claims that all living organisms are related by way of common descent. The comparison of which two species BEST supports her claim?
a
species I and species III
b
the unknown species and species IV
c
the unknown species and species II
d
species II and species IV
b. the unknown species and species IV
This is because the unknown species and species IV have identical DNA sequences for the protein being compared, suggesting a closer evolutionary relationship between the two species.