S-shaped Growth Form

The S-shaped, or sigmoid, growth form describes a population — small mammal populations are the chapter's example — that grows slowly to begin with, then accelerates into a faster growth phase, and finally slows down again as environmental resistance builds up around it. Unlike the abrupt stop of the J-shaped curve, this deceleration is gradual, and the population eventually settles into, and then maintains, an equilibrium close to the environment's carrying capacity, producing the characteristic elongated 'S' shape when plotted over time — a growth pattern that better represe …