## April 4, 2012

### Population Growth Modeling

Formula:

$\large N_{t}=((N_{t-1}\cdot r)+N_{t-1})-(((N_{t-1}\cdot r)+N_{t-1})\cdot D)$
This formula is used to find the number of birds in a certain population.  The first part of the formula is the population of the previous generation multiplied by the rate of increase (constantly 0.1) added to the previous generation's population.  The second part is then subracted from the first part.  The second part of the formula is the population of the previous generation multiplied by the rate of increase (constantly 0.1) added to the previous generation's population and then multiplied by the rate of decrease (D) due to diseases (.15).

This simple graph was constructed using the above formula.  It shows how the population of sparrows changed over 50 years.  Even though the population of sparrows was increasing at a 0.1 rate, the rate of disease exceeded it at a rate of .15.  As time passed by, the sparrow population decreased.  As a whole, this graphing activity was a great learning experience.  As models went from simple to increasingly complex, we learned how useful spreadsheets are for keeping information organized.  It's a good way to do business from a science standpoint because  it's an efficient way to do calculations with several numbers.