Video Transcript
What does this statement best describe? It is a way of identifying organisms using a series of two alternative
descriptions. (A) The Aristotelian system, (B) binomial nomenclature, (C) taxonomic ranking, (D) a
dichotomous key.
This question asks us about an identification system for organisms that involves
separating them using a series of two alternative descriptions. For instance, we could separate the group insects into organisms that have developed
wings, like butterflies, from those that don’t possess wings at all, like fleas. This is a very useful tool to help identify an organism based on its observable
characteristics.
In the case of our insect example, the group of winged insects could further be
divided into those that have large wings, like the butterfly, and organisms with
smaller wings, like mosquitoes. Notice how all these organisms still belong to the overarching group of insects. As you can see, this diagram has a series of junctures with two questions that are
usually opposites of each other.
Let’s go through the answer choices to see which one is correct. Answer choice (A), the Aristotelian system, is incorrect. This was a system proposed by Aristotle back in ancient Greece. This system arranged organisms in levels based on how complex or advanced they
appeared compared to others.
Answer choice (B), binomial nomenclature, is incorrect. This is a system for naming species, such as Homo sapiens for
humans, and is not used to identify organisms based on using alternative
descriptions.
Answer choice (C), taxonomic ranking, is incorrect. This is a system which involves classifying organisms based on their kingdom, phylum,
class, order, and so on.
Answer choice (D), a dichotomous key, is correct. Here, the prefix di- means two. And this is a system of identification that separates organisms by focusing on two
characteristics at a time, just like we can see in this diagram here. Therefore, the option that best describes the provided statement is given by answer
choice (D), a dichotomous key.
