Using discrete time steps, which is easier to describe that continuous change, the model for population growth is this:
nt = n0 x rate^t
try changing the blue numbers, for "r" (rate) and "n0" (start population) , below.
r: 10 time step (t) (nt) population at end of time step (nt)
n0: 2 0 n0 2
1 n1 20
2 n2 200
3 n3 2000
4 n4 2
5 n5 2
6 n6 2
7 n7 2
8 n8 2
9 n9 2
10 n10 2
try these hypothetical "r" values to begin, then try new numbers of your own
moose: 1.5 wolf: 1.2
rabbit: 5

house fly: 80 cockroach: 40 endangered tiger: 0.8
what does an r of "10" represent?

is this a logistic growth model? why or why not?

what is the value of r which makes the graph extremely steep?
what value makes the line flat?
can you model a declining population?