Limited Growth, Moving Ceiling

You'll learnthat real growth is logistic, leveling at a carrying capacity K set by conditions.

A population can look like it will grow forever — a few bacteria doubling every twenty minutes. It never does: the exponential J-curve is a brief opening act, real populations trace an S-curve that levels off at a carrying capacity K, and K itself rises in a wet year and falls in a drought. Eleven short steps; press Next for each one.

11 STEPS · 6 QUICK CHECKS · GROWTH IS LOGISTIC, NOT UNLIMITED · K TRACKS RESOURCES · FASTEST AT K/2 · v6

growth levels off at K · and K itself moves with the resources

Before you start

What you're looking at

A graph of population size against time, starting with a few bacteria doubling in fresh broth.

The question

Does a population grow forever or level off — and is its ceiling a fixed number?

Step 1 / 11