The following questions refer to Figure 27.1 below, which is the same as Figure 27.10 in the textbook.
In this 8-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population.

Figure 27.1
-E. coli cells typically make most of their ATP by metabolizing glucose. Under the conditions of this experiment, what should be True of E. coli's generation time (especially early in the course of the experiment, but less so later on)?
A)Generation time should be the same as in the typical environment.
B)Generation time should be faster than in the typical environment.
C)Generation time should be slower than in the typical environment.
D)It is theoretically impossible to make any predictions about generation time, under these conditions.

Question

The following questions refer to Figure 27.1 below, which is the same as Figure 27.10 in the textbook.
In this 8-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population.
  
Figure 27.1
-E. coli cells typically make most of their ATP by metabolizing glucose. Under the conditions of this experiment, what should be True of E. coli's generation time (especially early in the course of the experiment, but less so later on)?
A)Generation time should be the same as in the typical environment. 
B)Generation time should be faster than in the typical environment. 
C)Generation time should be slower than in the typical environment. 
D)It is theoretically impossible to make any predictions about generation time, under these conditions.

Quizplus · Accepted Answer

Under low-glucose conditions, E. coli cells will experience a lower rate of glucose uptake and therefore will have a slower generation time compared to the typical environment where glucose is more abundant. This is because E. coli cells will need to allocate more resources toward scavening small amounts of glucose, slowing their growth rate. While there may be some adaptation over time that could impact generation time, it is expected that early in the course of the experiment, the generation time should be slower than in the typical environment. Therefore, the correct answer is C.

The Following Questions Refer to Figure 27