Effect of temperature on the growth rate of Tetrahymena thermophila

  • Rachael Callaghan
  • Petra Catsi
  • Pravnit Kooner
  • Nevrose Mangat


In this experiment we studied the effect of temperature on the growth rate of Tetrahymena thermophila. T. thermophila are unicellular organisms that have been used in biology for many years and have a complex link with many key organisms in the ecosystem. We allowed the T. thermophila to grow in incubators at 3 separate temperatures, 13℃, 20℃, and 30℃. Samples were collected every hour on the first day and then our last sample was collected the next morning. Once all of our samples were collected we counted the number of cells in each. We predicted that T. thermophila will have the greatest growth at the highest temperature and through analysis of our results we were able to say that the temperatures were significantly different with a pvalue of less than 0.05. The T. thermophila that grew at 13℃ had the slowest growth compared to the growth at 30℃ (P < 0.031). There was not a significant difference in growth between the 20℃ and either of the 13℃ or 30℃ conditions (P < 0.115 and P < 0.574, respectively). Higher temperatures may result in a greater abundance of T. thermophila which could prove be to beneficial for other key organisms in the ecosystem that reply on these species.