Category: arthropods...

finding out that the more than one million species makes arthropods (arachnids, insects, crustaceans, myriapods) the largest group in the animal kingdom -- 84% of the known species of animals!
arthropod meaning jointed feet -- since their flexible leg joints are what allow them to move the way they do
exoskeletons' protection and support, which is nonliving but created by secretions of the epidermis
a bag filled with leaf mold from a forest floor will contain hundreds of arthropods
planktonic copepods reaching densities of 30,000 individuals per cubic meter in the surface waters of the Antarctic
insects breathing through spiracles -- holes in the abdomens
the development by bees and ants of efficient organizations
a spider's "mandala" web
most Arthropoda are characterized by a segmented exoskeleton with jointed limbs, a heart that lies in the upper part of the body, and a nerve cord that runs along the lower part of the body
arthropods include diplopods (millipedes) and chilopods (centipedes)