How is information about evolutionary or phylogenetic relationships useful in Classifications?

Answer 1

If you understand the evolutionary relationships of an organism, you can easily look at it's ancestors and those following it to try and classify the animal. If you were trying to classify as specific type of Jellyfish (Cnidarian), you could look at the sponges (Profiera) before it, and flatworms (Platyhelminthes) after it, and see that sponges are much less complex, but flatworms are much more so. Therefor, you can easily see what class they fall into, and where in the evolutionary time scale. Hope that helps!

Answer 2

It is useful in classification because it allows biologists to group organisms into categories that represent lines of evolutionary descent, or phylogeny, not just physical similarities.