Question

.4How might similarities and differences in genetic codes, or the proteins built as a result of these codes, be used to determine how closely related different species are?

Answer 1

DNA sequences and the protein amino acid sequences they encode, change by accumulating mutations over many generations. So the more similar to DNA sequences are, the more recently they shared a common ancestor. This is related to molecular clock. So try to look up molecular clock.

Answer 2

Think of it this way: let's say there was one big species, with very very similar DNA for all the organisms in that species.
Now, over time, this species broke off into different groups. Maybe it happened because they were separated by rivers or mountains, or lots of other possible reasons. So now the species start to adapt slowly through small mutations of their DNA code over the generations. Eventually, there are lots of different species that have all descended from that one "common ancestor."
So if you take two species in present day and you test their DNA, and you find out that their DNA is similar, what might you guess about how the two species developed? @Munekitaw<3