ScienceDaily: Biologists at the universities of York and Exeter have published new research which shows that an ancient symbiosis is founded entirely on exploitation, not mutual benefit. The researchers concluded that a single-celled protozoa called Paramecium bursaria benefits from exploiting a green algae which lives inside it, providing its host with sugar and oxygen from photosynthesis. Scientists have been debating for decades whether symbioses, like the Paramecium-Chlorella association, are based on mutual...