Invertebrate animals that have a SEGMENTED body, a tough EXOSKELETON, & JOINTED APPENDAGES. They are the most diverse and most successful animals of all time—3/4 of a million species have been identified.
An external skeleton much like a suit of armor that protects and supports the animal’s body. It is made from protein and a carbohydrate called CHITIN. Some exoskeletons are leathery (like a caterpillar), others are hard, like that of a crab. The exoskeleton does not grow as the animal grows.
are structures such as legs and antennae that extend from the body wall. This is the distinctive characteristic of arthropods, thus their name. The greek word arthron means “joint” and podos means “foot”.
When arthropods outgrow their exoskeletons, they undergo periods of MOLTING. They shed their entire exoskeleton as glands secrete a new exoskeleton.
Arthropods are classified based on the # & structure of their body segments & appendages-particularly their mouthparts.
Growth & development of insects usually involves metamorphosis, a process of changing shape and form. They undergo either complete metamorphosis (hatching into larva that look & act nothing like the parents) or incomplete metamorphosis (immature forms look very much like the adults).
A society is a group of closely related animals of the same species that work together for the benefit of the whole group. Individuals within the group are called castes. Ants, bees, termites, & some of their relatives form complex associations called societies.
28-4 Foldables
These invertebrates are characterized by spiny skin, an INTERNAL SKELETON, a water vascular system, & suction-cup like structures called TUBE FEET. Most adult echinoderms exhibit five-part RADIAL SYMMETRY. (*The larva of echinoderms are bilateral).
Adult echinoderms typically have no anterior or posterior end, & they lack cephalization. Most bodies are two-sided. The side in which the mouth is located is the ORAL surface, and the opposite side is the ABORAL surface.
: which is filled with fluid, carries out many essential body functions in echinoderms, including respiration, circulation, & movement.
Sea urchins & Sand Dollars; Brittle Stars; Sea Cucumbers; Sea Stars; Sea Lilies & Feather Stars;