middle layer of tissue in triploblastic animals; forms lining of coelom, muscles, kidneys, skeleton, circulatory system

animal lacking a cavity between the gut & outer cavity wall; area between the endoderm & ectoderm is filled with mesodermal tissue & organs; flatworms

animal that has a body cavity, but the body cavity is not completely lined by mesodermal tissue; roundworms

animal that possesses a true coelom; earthworms, arthropods, chordates, mollusks

external body covering; includes skin, glands, hair, beak, feathers, scales

skeleton formed inside the body & composed of cartilage &/or bone

skeleton formed on the outside of an animal's body

contractile tissue that allows animals to move; most common type of tissues found in animals

body system responsible for eliminating unnecessary wastes from body to maintain homeostasis

body temperature determined by environment

body temperature regulated internally

period of dormancy in winter

period of dormancy in summer

body system responsible for moving body fluids & nutrients throughout body

body system responsible for keeping the body supplied with oxygen and removing carbon dioxide

body system responsible for breaking down food into absorbable units & eliminating indigestible food stuffs (feces)

specialized body system responsible for reception of stimuli & conduction of impulses from one body region to another; allows an animal to interact with its environment

framework of the body; can be internal or external; allows for muscles attachment and aids in movement

animal body system composed of muscle fibers, muscles, and tendons; the tissues of this body system are contractile and aid in movement

sponges; aquatic suspension feeders; simplest of all animal phyla; body consists of pores, canals, and chambers for filtering water

animals that display radial (circular) symmetry and have tentacles with stinging cells; jellyfish, hydras, corals, anemones

acoelomate animals that have a definite head region and display bilateral symmetry; many are parasitic; flatworms, flukes, tapeworms

pseudocoelomate animals; most abundant of all animals; can be parasitic; includes roundworms, pin worms, hook worms, vinegar eels

soft-bodied animals that have a head-foot region used for feeding, locomotion, and sensory; can be very inactive suspension feeders to highly intelligent predators; snails, slugs, squid, octopus

segmented worms; include earthworms, leeches, and marine polychaetes

animals that have segmented bodies, jointed appendages, and rigid exoskeletons; most diverse phylum; includes arachnids, insects, crustaceans

"spiny skinned" animals; these animals have a calcium carbonate endoskeleton that can penetrate the skin creating spiny projections; includes star fish, brittle stars, sand dollars

animals that have a cartilage or bone endoskeleton; fishes, birds, amphibians, mammals