abdomen acceleration acron aedes ammonia amniote animal annelid anomalocarid anomalocaris anopheles anus appendage arachnid artery arthropod exoskeleton arthropod eye arthropod head problem articulata atelocerata aysheaia barnacle bee bilateria biological classification bird blood blood cell body cavity body plan book lung brachiopod brain branchiopoda brine shrimp burgess shale calcium carbonate cambodia cambrian cambrian explosion carboniferous caterpillar cenozoic centipede cephalocarida chelicerae chelicerata chitin circulatory system cockroach coelom commissure composite material compound convergent evolution copper cornea courtship crab crayfish cretaceous crustacean cuisine culex cuticle dna detritivore devonian digital object identifier dragonfly eardrum ecdysozoa ecological niche ecosystem ediacaran embryo endoskeleton entognatha enzyme epicuticle epidermis esophagus euarthropoda eumetazoa eurypterid euthycarcinoid excretion excretory system exoskeleton external fertilization feather feces felt filariasis foot frog gill gland glucose graham budd gram greek language hallucigenia hemocoel hemocyanin hemoglobin hexagon hexapod hexapoda honey horseshoe crab humidity hydrostatic skeleton inner ear insect insectivore institute of food and agricultural sciences integrated taxonomic information system internal fertilization international code of zoological nomenclature invertebrate invertebrate trachea japanese spider crab joint jumping spider jurassic kerygmachela kidney kinorhyncha late devonian extinction lens livestock lobster lophotrochozoa loricifera malacostraca malaria mammal mandible marrella maxilla maxillopoda membrane metabolism metamorphosis microdictyon millipede mite mitochondrial dna molecular phylogenetics motor nerve myriapoda myriochelata nematode nerve cord nervous system nitrogen opabinia ordovician ostium ostracod oviduct ovum oxford university press oxygen panarthropoda pancrustacea parapeytoia paraphyly parthenogenesis parvancorina pauropoda pedipalp penis peripatus phylogenetics piaroa plankton polarization pollination prawn procuticle prostomium protein protostome rna remipedia reptile respiratory pigment respiratory system scalidophora sclerite scorpion sea spider sediment sensory nerve seta sex sexual reproduction shrimp sidnie manton silurian silverfish smell sperm spermatophore spider spinneret spriggina statocyst subphylum symphyla tarantula tardigrade taste telson tetrapod thorax trilobite trilobitomorpha uniramia university of florida uric acid urine vertebrate wasp wax wikimedia commons wikispecies woodlouse xiphosura yellow fever