1. Arthropods Arthropods (Phylum Arthropoda) make up the largest phylum of animals – 3 out of every 4 animals are arthropods The largest group of Arthropods are the insects, which are rare in the sea The overwhelming majority of Arthropods in the ocean are crustaceans (class Crustacea) – Shrimp, lobster, crabs, copepods, barnacles

2. Phylum Arthropoda Arthropod means “jointed foot” Jointed appendages such as legs and mouthparts Body is segmented and bilaterally-symmetric Arthropods possess a tough, external skeleton, or exoskeleton – Composed of chitin – Secreted by underlying tissue, must molt or shed

3. Evidence of Arthropoda segmentationjointed appendagesexoskeletonKEY