Exponential growth ends (with a whimper)
Here's a second set of data on meningococcal growth rates. Your instructions are
1) to determine the exponential growth rate of the bacteria, and
2) to determine when growth stops being exponential.
|0 min||4.3 * 106|
|20 min||9.7 * 106|
|40 min||22 * 106|
|60 min||48 * 106|
|80 min||97 * 106|
|100 min||116 * 106|
|120 min||118 * 106|
|140 min||67 * 106|
Just look at the data first... what can you see with your bare eyes, so to speak?
About doubling time:
About the general shape of the population trajectory:
About when growth begins to slow down:
Now try plotting the data. (Applet may take several seconds to load).
Which time period showed exponential growth:
Let's look at an untransformed graph to figure out the doubling time. We could do this on the log-transformed graph above, but its difficult because the y-axis is on a log scale.
Where should we start, and what is the growth rate?
Copyright University of Maryland, 2007
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