Which taxonomic rank represents a group of closely related classes?

Which taxonomic rank represents a group of closely related classes?

• A. Genus
• B. Phylum
• C. Kingdom
• D. Order

Answer: (B)

In taxonomy, ranks are arranged from broad to specific, with each level grouping organisms that share more specific traits as you go down. A group that contains several closely related classes sits one level above class, which is the phylum. This level gathers multiple classes that share fundamental structural features and a common evolutionary history. For example, the phylum Chordata includes classes such as Mammalia, Aves, Reptilia, and Amphibia, all linked by core traits in their body plans. Another example is the phylum Arthropoda, which groups classes like Insecta, Arachnida, Crustacea, and Myriapoda, all united by features like jointed limbs and an exoskeleton. Because it collects related classes into a broader, cohesive unit, the correct rank is phylum.

In taxonomy, ranks are arranged from broad to specific, with each level grouping organisms that share more specific traits as you go down. A group that contains several closely related classes sits one level above class, which is the phylum. This level gathers multiple classes that share fundamental structural features and a common evolutionary history. For example, the phylum Chordata includes classes such as Mammalia, Aves, Reptilia, and Amphibia, all linked by core traits in their body plans. Another example is the phylum Arthropoda, which groups classes like Insecta, Arachnida, Crustacea, and Myriapoda, all united by features like jointed limbs and an exoskeleton. Because it collects related classes into a broader, cohesive unit, the correct rank is phylum.