ARTHROPODS Ch. 24

General Characteristics  Segmented bodies  Jointed appendages  Hard external skeleton (exoskeleton made of chitin)

General Characteristics  Molting  Open circulatory system  Brain with ganglia  Compound eyes

General Characteristics  Some aquatic arthropods have gills  Terrestrial arthropods have trachae (exchange CO 2 and O 2 change through holes called spiracles).

Examples of Arthropods  560 million years old  Crustaceans- live in the ocean  Crayfish, crabs, lobsters, barnacles  Arachnids  Spiders, ticks, scorpians, mites  Insects  Myriapods- many legs  Centipedes, millipedes

Extinct Arthropods  Trilobites  Eurypterids **Horseshoe crabs are the only closest living relatives.

Review  1) List 3 characteristics of arthropods that unite them as a single large group.  2) Name 1 group of arthropod that is now extinct. Name at least 3 groups still in existence today.

INSECTS

Keys to Insect Success  Ability to fly (1 or 2 pairs of wings)  Diverse feeding habits  Many types of mouthparts  Digestive enzymes to eat unusual food

Keys to Insect Success  Video clip Video clip Video clip  Metamorphosis- body form changes from juvenile to adult  Larva, pupa, adult

Impact of Insects  Bees & flowers  Termites & wood  Insect Medicine? Insect Medicine? Insect Medicine?  Diseases/ pests  Entomology- study and classification of insects

Insect Collection  Some Major Orders of Insects Some Major Orders of Insects Some Major Orders of Insects

Lubber Grasshopper Dissection

Grasshopper Head  Compound eyes  Simple eyes  Mandible  Palps  Antennae

Grasshopper Thorax  Tympannic membrane  Jumping legs  Walking legs  2 pairs of wings

Grasshopper Abdomen  Spiracles  Ovipositor (if female)

Grasshopper Internal Anatomy