How Environmental Factors Affect a Yeast Population’s Ability to Reproduce
The objective of this experiment is to emphasize the influence that limiting factors have on a population. This lab tests yeast, a common component in baking, against two environmental factors (changes in temperature or concentration) to see what effect these have on the population dynamics of the yeast over a period of 72 hours. There are two sections of tests included in this experiment: biotic and abiotic factors.
The abiotic factor being tested here is what effect the temperature of the yeast’s environment has on its ability or inability to reproduce efficiently. The lab tests the yeast in three separate temperature settings: a cold temperature (4ᵒC), room temperature (22ᵒC), and a hot temperature (30ᵒC). Here, the independent variable is the temperature of the yeast habitat and the dependent variable is the amount (in mL) of CO2 gas produced by the yeast.
The biotic factor in this experiment is what effect the concentration of the yeast has on its ability or inability to reproduce efficiently. The lab tests three different concentrations of the yeast: add 0.25 mL, 0.5 mL, or 1 mL of yeast suspension to the test tube. The independent variable is the amount of yeast concentration added and the dependent variable is the amount (in mL) of CO2 gas produced by the yeast.
Yeast is a single-cell fungus that produces carbon dioxide (CO2) as a byproduct of cellular respiration. Therefore, the more yeast cells in an area, the more CO2 they will be able to produce. Yeast has many uses as a common ingredient in many foods and drinks, such as alcoholic beverages like beer and wine, and acts as a leavening agent in baking cakes, bread, and other foods by converting the fermentable sugars in the food into CO2. This is what makes the dough in many foods rise while baking. This lab closely monitors a yeast population over a period
References: Population Size. (n.d.). Retrieved May 26, 2015, from https://www.wou.edu/las/physci/ch371/lecture/popgrowth/carrying.htm