Arthropods By Aaron Williams

Characteristics Typical arthropod is segmented They are bilateral symmetry, have an exoskeleton, and jointed appendages Pollinate many of the plants on Earth Molt because they out grow their exoskeleton In most arthropods they have 3 body segments: head, thorax, and abdomen Arthropods can exchange gas in 3 different ways: gills, book lungs, or tracheal tubes Have well developed nervous system: double ventral nerve cord, anterior brain, and ganglia Reproduce sexually, but some arthropods exhibit parthenogenesis which is a form of asexual reproduction

Arachnids Arachnids are spiders, scorpions, ticks, and mites Arachnids have 6 pairs of limbs First pair are called chelicerae, which is located near the mouth, often modified as fangs or pinchers Second pair is called pedipalps, used for handling food and for sensing The other 4 pairs are used for locomotion

Crustaceans Includes crabs, lobsters, cray fish, pill bugs, shrimp, and barnacles Exchange gas thru gills Two compound eyes usually located on stalks Most live in aquatic environments, if not, they are found in moist environments Many have 5 pairs of walking legs Have mandibles for crushing food

Chilopoda Chiloods are centipedes Have flattened bodies Found in damp environments Are carnivorous and eat soil arthropods Have Malipighian tubules for waste excretion Have tracheal tubes for gas exchange

Diplopoda Diplopods are millipedes Eats mostly plants and dead material Live in damp/moist environments Have thousands of legs Are able to spray obnoxious-smelling fluids to escape predators

Merostomata Merostomata are horseshoe crabs Found in oceans Have been unchanged since the Cambrian period 4 known species Migrate to shallow waters during mating season Females lays their eggs on land, underneath the sand

Insecta Includes butterflies, beetles, grasshoppers, bees, and a lot more Largest group of arthropods 750,000 known species Reproduce sexually and go thru metamorphosis “Incomplete and complete”