Phylum Arthropoda
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Excrectory System
Some release liquid waste in the form of ammonia Some release it in form of uric acid Most contain nephridia which ac as "little kidneys" Respiratory System Wide variety of forms of respiration Small arthropods diffuse oxygen directly through skin Other may have gills, books lungs or tracheae Nevous System Have "ladder-like" nevous system Brain is in head, located above the esophagus Two main nerve cords running length of the body connect as from of ganglia in each segmeant Sensory Organs Compound eyes some can only direct the direction light is coming, but spiders, for instance, can form images Also can comtain antenna or setae that sense touch Reproduction Usually use sexual reproduction most are dioccious(males or females); very few are hermaphroditic Some use external fertilization, others use interal fertilization Most lay eggs Many use metamorphosis Major Subphyla Chelicerata contains arachnids(spiders0 and horseshoe crabs Mandibulata contains several major classes: Crustacea (crabs, lobster, crayfish) Insecta (insects) Chilopda (centipedes) Diplopoda (millipedes) |