Logistic Growth (S-Curve): Populations grow exponentially until resources become scarce, then level off at K.
Carrying Capacity (K): The maximum population size the environment can sustain indefinitely.
Overshoot & Dieback: Rapidly growing populations often exceed K, deplete resources, and suffer a catastrophic population crash.
Tags
PopulationCapactiy (K)OvershootDieback
Carrying Capacity (K)
500 pop
Reproductive Rate (r)
High (Severe Overshoot)
The Reindeer of St. Matthew Island (Classic AP Example):
Introduced to an island with abundant lichen and no predators, the population exploded (exponential growth), vastly exceeding the carrying capacity. They ate the lichen faster than it could regrow. The result was a catastrophic dieback from starvation, permanently lowering the island's K value.
AP Exam Tip
A major misconception is that populations smoothly touch the K line and stop. In reality, practically all species overshoot and oscillate around K. If the overshoot severely damages the habitat (like overgrazing), K itself will drop permanently!