Which statement differentiates exponential population growth from logistic growth?

Which statement differentiates exponential population growth from logistic growth?

• A. Exponential growth is unlimited; logistic growth levels off as resources become limiting; carrying capacity is the maximum population size the environment can sustain indefinitely.
• B. Exponential growth has a carrying capacity; logistic growth has no limit.
• C. Exponential growth shows declines with time; logistic growth increases linearly.
• D. Exponential growth occurs only in bacteria; logistic only in plants.

Answer: (A)

When population growth is described, the key idea is how resource limits shape the curve. Exponential growth happens when resources are plentiful, so the population increases rapidly in proportion to its current size, producing a steep, unchecked rise. Logistic growth brings in the reality that resources are limited; as numbers climb, growth slows and the population levels off near the carrying capacity—the maximum number the environment can sustain indefinitely. This distinction is exactly what the statement conveys: exponential growth is unlimited, while logistic growth levels off because resources become limiting, with carrying capacity defining that sustainable limit. The other ideas don’t fit: exponential growth doesn’t inherently have a carrying capacity, the notion of exponential declines and linear increases misstates how these curves behave, and growth modes aren’t exclusive to particular groups like bacteria or plants.