Echinodermata
common name (examples): sphere-shaped sea urchins, sea cucumbers, starfish, disk-shaped sand-dollars
habitat: ocean floor
body plan (symmetry): radial symmetry
skeletal system: internal skeleton
water vascular system: spiny skin, and a network of tubes and appendages
oral and aboral surfaces: no skeleton, rough, soft
feeding, digestion, and elimintation: enormous surface area exposed to the surrounding water, echinoderms' cells can exchange gases directly with the water
respiratory system: coming soon
nervous system: few nerve cells, adequate sense of taste and smell
reproductive system: seperate sexes that release egss and sperm into the water








Arthropoda
common name (examples): trilobites, man-faced beetle, peripatus
body plan (segmented bodies, jointed appendages, exoskeleton): segmented bodies, jointed appedages, and are surrounded by a tough exoskeleton
metamorphosis: molting not only allows arthropods to change size, as well as allowing them to change their form and shapes
structures: atennae, book gills, spiracles, book lungs, tracheal tubes, gonads, Malpighian tubules
(Subphyla) Chelicerata, Crustacea, Uniramia
characteristics of subphyla: body that is divided into two parts - a cepholothorax and a abdomen. cephalothorax - head and carries the legs. abdomen - most internal organs