Final answer:
Synapomorphies such as compound eyes, a chitinous exoskeleton, and jointed appendages define the phylum Arthropoda. This phylum includes a myriad of species with diverse features and adaptations like chelicerae in Chelicerata or biramous appendages in crustaceans.
Step-by-step explanation:
Compound eyes, a chitinous exoskeleton, and jointed appendages are synapomorphies for the phylum Arthropoda. This phylum, which is part of the superphylum Ecdysozoa, represents the most diverse and abundant group of animals on Earth. Arthropods are characterized by their segmented bodies, and traditional classification has been based on various morphological features such as the type and arrangement of appendages.
For example, chelicerae are a modified first pair of appendages in the subphylum Chelicerata, which includes spiders and scorpions. The biology of arthropods is complex, with adaptations like gills, tracheae, and book lungs for respiration, as well as unique life stages in both aquatic and terrestrial species.
The phylum Arthropoda encompasses an extremely diverse range of organisms, all sharing the common features of a chitinous exoskeleton and jointed appendages. Among these organisms are crustaceans, which typically have two pairs of antennae and biramous appendages, and insects that may possess wings or have evolved to be wingless. The functional and structural adaptations seen throughout the phylum illustrate the evolutionary success of these critters.