Arthropoda (Jointed Limbs)

Characteristics of Arthropoda

• Cephalization: well developed head
• Nervous tissue is concentrated towards the head
• Head is specialized for feeding and sensing
• Open circulatory system
• Jointed appendages
• Arthro-pod = "Jointed"-"foot"
• Specialized function
• Walking
• Feeding
• Sensing
• Reproduction
• Defense Example: scorpions tail
• Appendages are added to the main body
• Segmented body
• developed through Hox genes
• Sclerotized cuticle
• Made of chitin (very strong)
• Creates exoskeleton
• Molting needed to grow
• Provides support for muscles to contract against
• Structure enables life on land (fight gravity)
• Tagmatization: grouping of segments for a specialized prupose
• Segmented body and jointed appendages perform specialized functions
• Allows for division of labor
• Increased arthropod diversity (adaptive radiation)
• Cephalothorax: head and thorax are merged