Drosophila are often of interest to biologists because of their lifespan, mating habits, and the way in

which there cells are very lab friendly.

As a historical example from post World War 2 Calculus books we refernce a study .* Growth of

a fruit fly population in a controlled experiment ,and examine a population of Drosophila over a 23

day study using Microsoft Excel as our learning device.

To view a very close estimate to the original data set and an initial chart click here


The chart for the data set shows the days (1-50) ploted against the fly population.

We can investigate this further in elementary and intermediate directions.

We now examine the chart of the actual population growth ploted aginst the average growth over the entire period of the 50 day study.


As one may see the average( series 2, pink) is only a useful estimate of the population on a few

isolated instances. The advanced student may attempt to find a function that maps a unique point of

the number of flies for each specific day.

To view the entire data set with all charts click here

This example is used to illustrate the need for higher mathematics when one wants more than just a

general idea about what is happening for the function. Concetps of a limit can be discussed an

estimate of the derivative can be calculated (at least estimated with this data set) and a derivative at a

certain point can be compared to the whole. Below we estimated the instantaneous rate of change

on day 23 (growing about 20 flies per day) and ploted it against the graph of the entire function

and the average growth rate.


To see the entire data set and charts using the estimated derivative click here


Is this growth or rate of increase similar to financial growth or any other type of function ?

* Growth of a fruit fly population in a controlled experiment. (Source: Elements of Mathematical Biology by A.J. Lotka, 1956, Dover, New York, p.69.