Concept: Relationship Between Organisms (Under Unit: Ecology) This is the HD (high-resolution) version with no watermark. If you'd like to save money by using the FREE versions (lower-res, with watermarks), you can find them at the Owlcomics Official Homepage: http://owlcomics.com/ Key Concepts in this Comic: Predation, Competition, Carnivores, Symbiosis, Autotroph, Heterotroph, Specialist, Generalist, Etc.