your poster will contain information on all of the 6 kingdoms as well as many of the phyla under each kingdom. Pictures of the following organisms will be helpful, remember you want smallish pictures because you have a lot to fit on your poster :)
ALSO- your poster is your guide map through your test, the more complete your poster is in terms of information, the better you'll do on your test- your team may use the poster at their table, however, you will not be able to help each other- different tests for each of you and NO TALKING.
Animals: worm, sponges, jellyfish (aka Cnidaria), molluscs ( clams, etc), arthropods, insects, fish, amphibians, birds, reptiles mammals.
Plants: moss, ferns, gymnosperms and angiosperms
Fungi: mushrooms
protist: single celled eukaryotic organisms like- amoebas, parmecium, euglena and diatoms
http://www.pbs.org/wnet/nature/episodes/crime-scene-creatures/video-diatom-detective/5208/
archaea- extremophiles - single celled prokaryotic organims that live in "extreme" environments
more info on extremophiles
http://www.pbs.org/wgbh/nova/nature/lives-of-extremophiles.html
Eubacteria- monera- singled celled prokaryotic organisms that live IN and around you - staph, strep..