Characteristics and classes of Arthropods By Michael Dewar
Class Arachnida Spiders, scorpions, mites, and ticks belong to this class. Spiders have 2 body regions, 6 pairs of jointed appendages, no mandibles for chewing 1st pair of appendages are chelicerae, 2nd pair are pedipalps. Make webs from spinnerects,
Class Crustacea Aquatic, exchange gas a water flows over feathery gills. 2 pairs of antennae, have mandibles for chewing. Have two compound eyes, jaws open and close from side to side, 5 pairs of walking legs used for walking, seizing prey, cleaning other appendages. Crabs, lobsters, shrimps, crayfishes, barnacles, water fleas, and pill bugs are in this class. Some crustaceans have 3 body sections others only have two. Sow bugs and pill bugs are the only land crustaceans, must live where there is moisture which aids in gas exchange
Class Chilopoda Centipedes are the only animals in this class. Flattened bodies, many jointed legs. Carnivorous eaters, and eat soil arthropods; snails, slugs, and worms.
Class Diplopoda Millipedes are the only animals in this class. Millipedes eat mostly plants and dead material on damp forest floors. Millipedes do not bite, but they can spray obnoxious-smelling fluids from their defensive stink glands. Have cylinder shape bodies.
Class Mermosota • Horseshoe Crabs belong to this class • Considered to be living fossils • Similar to trilobites b/c they are heavily protected by an extensive exoskeleton • Forage on sandy or muddy ocean bottoms for seaweed , worms, and mollusks • Migrate to shallow water during matting season • Females lay eggs on land, buried in sand above the high water mark • Newly hatched eggs look like trilobites.
Class Insecta/ Insect Reproduction • Mate once or mostly a few times during their lifetimes . • Eggs fertilized internally, in some species form shells around them. • Lay a large number of eggs. • Many females insects are equipped with an appendage that are modified for piercing the surface of the ground or into wood.