Order A

• order acarina • order accipitriformes • order actinaria • order actiniaria • order actinomycetales • order actinomyxidia • order aepyorniformes • order agaricales • order alcyonaria • order alismales • order amoebida • order amoebina • order amphipoda • order anacanthini • order anaspida • order andreaeales • order anguilliformes • order anoplura • order anostraca • order anseriformes • order anthocerotales • order anura • order aphyllophorales • order aplacophora • order apodes • order apodiformes • order apterygiformes • order arales • order araneae • order araneida • order aristolochiales • order arms • order artiodactyla • order aspergillales • order auriculariales