1. Invertebrates 4
Phylum Arthropoda

2. Phylum Arthropoda: “jointed foot”

3. Basic Arthropod Features (cont.)
Paired, jointed appendages
joints allow for flexibility
Segmentation
In some, have similar segments throughout body
In most: Segments combined into specialized body regions
Crustaceans have 2 regions: cephalothorax, abodomen
Insects have 3 regions: head, thorax and abdomen
Exoskeleton
Same materials also in mouthparts, wings, eye lens

4. Focus on Molting Function: growth New exoskeleton built under old
stretching by water or air in the digestive system and hemocoel
vulnerable to predators while hardening
mating can coincide with soft shell in female crabs
Some arthropods grow all life
Hormonal control

5. Subphylum Crustacea
Examples: Lobsters, crabs, shrimp, barnacles, copepods, etc..

6. Subphylum Unirama
Insects, centipedes, millipedes

7. Subphylum Chelicerata
Spiders, mites, scorpions, horseshoe crabs

8. Various aspects of anatomy, physiology and behavior
Feeding
Class Crustacea
Class Insecta
Subphylum Chelicerata
Circulation/gas exchange
Open circulatory system
Respiration varies amongst subphyla and classes
Class Crustacea: gills
Class Insecta: tracheal system. CARRIES OXYGEN AND CO2
Subphylum Chelicerata: tracheal system, book gills and book lungs
Water/ion balance and ammonia excretion
Crustacea: gills and green glands
Insecta and Chelicerata: Malpighian tubules

9. Various aspects of anatomy, physiology and behavior
Nervous system
Cerebral ganglia
Ventral nerve cord (paired, fused)
Ganglia in each segment , or one ganglion for several segments
Reproductive systems
Usually internal fertilization
Spermatophores
Sperm storage

10. Review: Features