Cladistic taxonomy is based upon

Question

A. both overall similarity and phylogenetic relatedness.

B. overall similarity only.

C. phylogenetic relatedness only.

D. is incorrect.

E. can only be applied under certain conditions.

Answer 1

For this question, let's start by eliminating answers D. and E. They don't make sense. Cladistic taxonomy is a technique for organizing different organisms, so it doesn't make sense for it to be "incorrect". And by now we should know that this useful technique is applied to all living things, not only in "specific circumstances".

Now we have to evaluate answers A., B., and C. Let's do this by comparing phylogenetic relatedness vs. overall similarity. We will quickly see that overall similarity is too vague to be used in scientific processes. A dolphin and a shark have many similarities, but are not exactly close to each other in terms of evolutionary ancestry or actual homologous physical structures. Using "overall similarity" would not be helpful for organizing organisms evolutionary history, because it would suggest that birds being similar to insects and bats, or snakes being similar to eels and worms means that you can group them together on a clad. You can not.

So, we can eliminate any answer with overall similarity in it, leaving us with answer C. as the correct answer "phylogenetic relatedness".