Every species, whether microbial or macrobial, has its own specific niche - i.e. the biotic and abiotic conditions in which it can live, grow, and reproduce. How niche preferences evolve has been studied particularly in macrobes, but fundamental questions about niche evolution in microbes remain unanswered. Here, we use comprehensive ciliate phylogenies along with corresponding metadata about the temperature, precipitation, nutrient conditions and other variables for each ciliate taxon. I will model how these variables evolve along the phylogeny using tools that allow rate variation in time and across lineages. Questions investigated will include: - what is the mode of niche preference evolution? - is there rate variation of niche evolution between lineages? - is there a difference between soil and marine clades?