Gnotobiology is ecology.
D000821:Animal Feed; D000818:Animals; D001419:Bacteria; D002175:Candida; D004463:Ecology; D004926:Escherichia coli; D005243:Feces / Q000382:microbiology; D005856:Germ-Free Life; D006168:Guinea Pigs; D007778:Lactobacillus; D007958:Leukocyte Count; D007962:Leukocytes / Q000032:analysis; D051379:Mice; D013026:Space Flight; D013210:Staphylococcus