ARTHROPODS

Arthropods have segmented bodies that are bilaterally symmetrical. There are paired, jointed appendages that usually end in claws. The hard exoskeleton is mostly chitin. There is a ventral nerve cord and a simple dorsal heart.

We want to be able to recognize 5 classes of Arthropods

  • Diplopoda - Millipedes or "thousand-legged-worms
    • 1 pair of antennae
    • 1 chewing mouthparts
    • 2 pair of legs per body segment
    • body segments round cross section
    • usually feed on decaying organic matter but may feed on roots or leaves touching the ground

  • Chilopoda - Centipedes
    • 1 pair of antennae
    • 1 pair of fangs or "poison legs"
    • 1 pair of legs per body segment
    • body segments flat in cross section
    • predators - generally beneficial

    Crustacea Pillbugs, sowbugs crayfish (crawdads), shrimp, lobsters, and crabs.

    • 2 pairs of antennae
    • 2 main body regions
    • 5 pairs of walking legs
    • breathe with gills, sowbugs and pillbugs are the main terrestrial forms- need high humidity
    • usually feed on deacying organic matter but may feed on roots or leaves touching the ground

  • Arachnida - spiders, ticks, mites, scorpions, daddy-longlegs
    • no antennae
    • head and thorax joined into 1 section (cephalothorax)
    • 4 pairs of walking legs
    • venemous jaws

  • Insecta
    • 1 pair of antennae
    • 3 body parts
    • 3 pairs of legs
    • chewing, rasping, or pirecing-sucking mouthparts
    • some have wings in the adult stage

Orders we are covering include