1. Phylum Arthropoda

2. Arthropoda Includes…
Spiders, scorpions, ticks, mites, crustaceans, millipedes, centipedes, insects.

3. Largest Phylum
More than ¾ of all known species
Over 900,000 species

4. Characteristics Exoskeleton—made of at least some chitin
Jointed appendages
Open circulatory system
Complete digestive system
Excretory system
Dorsal brain and well developed sensory organs

5. Body Form Head and trunk OR Head, thorax, and abdomen OR
Cephalothorax and abdomen

6. More Characteristics
Exoskeleton serves as point of attachment for muscles
This allows for a complex muscular system
Respiration occurs through one of the following: gills, trachae, spiracles, book lungs, or body surface

7. Why So Successful?
1. Exoskeleton protects, but does not limit mobility
Exoskeleton must, however, be shed
2. Specialized appendages

8. Why So Successful? 3. Air piped directly to cells
4. Highly developed sensory organs
5. Complex behavior patterns (ants and bees)

9. Why So Successful? 6. Metamorphosis: uses diverse resources
Reduces competition
Each stage lives and feeds on different things

10. Phylum Arthropoda