Final answer:
Arthropods are categorized based on their characteristics, such as whether their appendages are uniramous or biramous. Crustaceans have biramous appendages, while insects and myriapods have uniramous appendages. Trilobites, which are extinct, also had biramous appendages.
Step-by-step explanation:
Arthropods are a phylum of animals that have a segmented body and jointed appendages. Drawing an arthropod dichotomy involves categorizing arthropods based on their characteristics. One way to do this is by identifying whether their appendages are uniramous (one-branched) or biramous (two-branched).
For example, crustaceans have biramous appendages, whereas insects and myriapods have uniramous appendages. Trilobites, which are now extinct, also had biramous appendages. By taking into account other features such as mouthparts, body subdivisions, and modifications of appendages, we can further classify arthropods into various groups.