There are cells which don't live or behave by the accepted set of rules. These cells have evolved adaptations to survive the unusual niches they inhabit, and include bacteria, eukaryotes and other life-forms that do not seem to fit into any neat category. Of course to these cells their niches are not unusual at all - "extreme"  is a rather anthropocentric term, and presumes to define what is normal. We will talk about these cells and their adaptations in great detail, come Wednesday, and try to draw out some basic evolutionary concepts underlying cellular development and the gradual appearance of multi-cellularity. And on Tuesday, Prof. Samir Damare from National Institute of Oceanography, Goa is visiting NCBS to kick off this week's celebration of Xtreme Biology with a talk about the extreme environment of the deep sea and the organisms that dwell there.