The law of conservation of mass states that matter cannot be created, yet matter is sometimes gained or lost to an ecosystem. what is the reason for this seeming contradiction? the law of conservation of mass states that matter cannot be created, yet matter is sometimes gained or lost to an ecosystem. what is the reason for this seeming contradiction? heterotrophs convert heat to energy. chemoautotrophic organisms can convert matter to energy. ecosystems are open systems; therefore, matter can be moved in/out of an ecosystem from/to another ecosystem. photosynthetic organisms convert sugars to more complex organic molecules. detritivores convert matter to energy.