In this video, we're going to begin our lesson on generation times. Scientists can actually measure the growth rate of a microbial population by calculating its generation time. The generation time, also sometimes referred to as the doubling time, is the amount of time it takes for a population to double in the number of cells. In other words, the generation time or the doubling time represents how long it takes for binary fission to occur and for binary fission to create a new generation of cells. Recall from our previous lesson videos that binary fission is the process by which prokaryotic cells divide. The generation time is simply how long binary fission takes. Different microbes tend to have different generation times. Some microbes will divide really slowly, whereas other microbes will divide very fast.

If we look at our image below, we can get a better understanding of the different generation times. On the left, notice we are showing you a microbe that divides very slowly, like this turtle, which we know moves very slow. You can see that over a period of 30 minutes, this prokaryotic cell is able to divide into 2 cells. The generation time for this microbe is 30 minutes. On the right side of the image, we're showing you a microbe that divides very fast, like this bunny rabbit you see here. Notice that in half the time, in just 15 minutes, this microbe is able to divide to create a new generation of cells. Over a period of 30 minutes, these cells are able to divide once again. This microbe on the right is going to have a much faster generation time. You can see that shorter times represent faster binary fission, whereas longer times represent more extended binary fission processes.

This concludes our brief introduction to generation times. Later, in our next video, we'll discuss how scientists can use these generation times to predict how many cells there will be after a given amount of time. So I'll see you all in that next video to talk about that.