Superphylum Ecdysozoa: Arthropods

Free Response

Describe the various superclasses that phylum Arthropoda can be divided into.


The Arthropoda include the Hexapoda, which are mandibulates with six legs; the Myriapoda, which are mandibulates with many legs and include the centipedes and millipedes; the Crustacea, which are mostly marine mandibulates; and the Chelicerata, which include the spiders and scorpions and their kin.

Compare and contrast the segmentation seen in phylum Annelida with that seen in phylum Arthropoda.


Arthropods have an exoskeleton, which is missing in annelids. Arthropod segmentation is more specialized with major organs concentrated in body tagma. Annelid segmentation is usually more uniform with the intestine extending through most segments.

How do terrestrial arthropods of the subphylum Hexapoda impact the world’s food supply? Provide at least two positive and two negative effects.


Insects are the predominant members of the subphylum Hexapoda.


  • Pollination;
  • Eliminate pests;
  • Cheap food source;
  • Produce food products (ex. honey)


  • Damage to food crops;
  • Transmit disease to agricultural workers;
  • Contaminate/spoil food;
  • Destroy buildings storing food crops