lab notebook
Investigating Bacterial Growth

PREDICTION

Predictions of Bacterial Growth in Aerobic and Anaerobic Conditions
Explain whether or not you think all bacteria need oxygen in order to grow.

OBSERVATIONS 

Record your observations for each bacteria type in aerobic (with oxygen) and anaerobic (without oxygen) conditions.

Table 1. Observations of Bacterial Growth in Aerobic and Anaerobic Conditions
Bacteria species	Observations	
	Amount of growth in medium A (environment with oxygen) 	Location of growth in medium B (environment without oxygen)	
B. stearothermophilus 
Vial 1			
C. sporogenes
Vial 2			
E. coli
Vial 3			

RESULTS

Based on the observations you recorded, complete the table below. Enter one of the following: “bacteria need oxygen,” “bacteria don't need oxygen,” or “bacteria can grow with or without oxygen” for each species of bacteria listed below.

Table 2. Oxygen Needs
Bacteria species	Oxygen needs	
B. stearothermophilus 
Vial 1		
C. sporogenes
Vial 2		
E. coli
Vial 3		

ANALYZE AND CONCLUDE

1. Conclude Based on your observations, is it possible that bacteria can thrive in a sealed can and cause vegetables to spoil?

2. Compare and Contrast How did the presence of oxygen affect bacterial growth?

3. Evaluate What factors in addition to oxygen might influence the growth of different types of bacteria?

4. Infer Scientists hypothesize that bacteria may have been among the first living organisms on Earth. If this is true, which type of bacteria do you think was the first to develop on Earth: bacteria that need oxygen or bacteria that don't need oxygen? Explain your answer.

5. Infer What might the results of this lab mean in terms of the ability for microbes to live and thrive on other planets or moons that don't have oxygen in their atmospheres?