Final answer:
The exponential growth model results in a J-shaped curve and occurs when resources are not limiting. Logistic growth, which produces an S-shaped curve, occurs when resources become scarce and the population size levels off at the carrying capacity. Zero population growth happens when the death rate equals the birth rate.
Step-by-step explanation:
The exponential growth model shows a J-shaped curve because the population isn’t limited by resources. Zero population growth occurs when the death rate is equal to the birth rate. Once a population reaches the carrying capacity, the population will stabilize.
Exponential growth is characterized by abundant resources and a rapid increase in population, resulting in a J-shaped curve. However, in the real world, resources are not unlimited, leading to logistic growth. Logistic growth is a more realistic model that shows how population expansion decreases as resources become scarce, producing an S-shaped curve. This curve initially rises steeply during exponential growth, then the growth rate slows down as resources are depleted until finally leveling off when the carrying capacity of the environment is reached.
Carrying capacity, which is denoted by the symbol K, signifies the maximum number of individuals that an environment can sustainably support. When a population size approaches carrying capacity, resources become limited, intraspecific competition increases, and the growth rate slows. It's essential to understand these concepts to predict and manage population dynamics in various ecological contexts.