Phylum Arthropoda: Jointed Legs
Defining Characteristics
- exoskeleton made of chitin (provides strength and protection)
- appendage formation: can be used many different ways
- respiratory system: gills (aquatic), tracheids (terrestrial), book lungs (spiders)
- segmentation: specialized to form many body regions
- reproduction: all sexual, all sexes are separate
- nervous system: one ventral nerve cord and a small brain (cephalization)
- open circulatory system with hemocoel and improved single heart
- 5 classes: Chilopoda. Diplopoda, Crustacea, Arachnida, Insecta
- most dominant phylum on Earth
- jointed walking legs
- bilateral symmetry
- Malphigian tublues
- triploblastic
- antennae
- specialized mouth parts
- food tubes with mouth and anus
- true coelom
- protostomes