
The Phylum, Arthropoda (Arthropods) include the classes of Insects, Arachnids, Millipedes, Centipedes and Crustaceans.
All Arthropods are invertebrates (animals with no backbone). All have jointed legs and an exoskeleton (skeleton on the outside).
In addition to the above requirements for generally describing an Arthropod (jointed legs, exoskeleton):
The insects have 6 legs (in their adult stage), 3 body parts (head, thorax, abdomen) and one pair of antennae.
The Arachnids include spiders, scorpions, ticks, mites, solpugids ("sun spiders"), amblypigids (tailess whip scorpions), uropigids (vinegaroons), and many others. They all have 8 legs and 2 body parts and no antennae.
Millipedes have several body segments, two pairs of legs per apparent body segment, one pair of antennae. They are generally harmless scavengers, herbivores and detritus feeders.
Centipedes have several body segments, one pair of long running legs per body segment, one pair of long antennae. They are generally predators and are venomous.
Crustaceans are mainly aquatic or marine arthropds and include crabs, lobsters, shrimp, barnacles etc. They have 3 segments, 10 legs and 2 pair of antennae. We are all familiar with the Terrestrial (land dwelling) Crustaceans, Rolie-polies and Sow Bugs.
|