CASE STUDY: Advanced Population Growth

Directions:

Use the information here to build a working model of population growth. The question being studied is: "how does the population change over a period of time?"

Factors that are important for this model:

(you need to decide which STELLA icon to use and how to connect them!)

Births: the number of people who are born over time

Deaths: the number of people who die over time

Birth fraction: the percentage of the population that is being born

Food: the amount of food that is available for the people to eat

Consumption: the amount of food that is eaten by the people

Food per capita: the amount of food available to each person. "Per capita" means "for each person". What is the mathematical definition of this?

Consumption per day: the amount of food eaten per day. This number depends on how much food there is available per person. The more food per person (per capita), the more consumption per day

Death fraction: in this model, we are assuming that the percentage of the population that dies is directly related to how much food there is per capita (per person). As the food per capita increases, the death fraction decreases.

Model details

Simulation time: 24 years
dt (recommended): 0.125
Initial amount of food: 1500 pounds
Initial number of people: 10
Birth fraction: 30%
Consumption per day: defined as a set of numbers related to food per capita

Food per capita (pounds per person)		Consumption per day (pounds)
0		0
1		0.205
2		0.305
3		0.33
4		0.335
5		0.335
6		0.335
7		0.335
8		0.34
9		0.34
10		0.345

Death fraction:

defined as a set of numbers related to food per capita

Food per capita (pounds per person)		Death fraction
0		100%
1		77.5%
2		22.5%
3		7.5%
4		4%
5		4%
6		4%
7		4%
8		4%
9		4%
10		4%

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