Final answer:
Exponential growth occurs when resources are unlimited, leading to a population increasing rapidly, while logistic growth takes over when resources become scarce, leading to the population leveling off at the environment's carrying capacity. The carrying capacity is affected by both biotic and abiotic factors, which influence the rates of birth, death, immigration, and emigration within a population.
Step-by-step explanation:
Exponential and logistic growth models describe how populations change over time in relation to carrying capacity and the availability of resources. In an environment with unlimited resources, a population grows exponentially, which means the growth rate increases as the population size increases. This is represented by a J-shaped curve and assumes no limiting factors such as food scarcity, space, or predation which would otherwise restrict population growth.
However, in the real world, resources are not infinite and populations may be subject to various limiting factors, both biotic and abiotic, including competition, disease, climate, and habitat destruction. These factors influence births, deaths, immigration, and emigration. When these factors come into play, the population stops growing exponentially and starts following a logistic growth model, forming an S-shaped curve. The logistic model reflects a situation where population growth slows as it approaches the carrying capacity (K), which is the maximum population size that the environment can sustain without being degraded.
Carrying capacity is dynamic and varies annually due to changes in abiotic and biotic factors. For instance, weather can alter the availability of resources, directly impacting the carrying capacity. Additionally, events like natural disasters and interspecific competition also play a role in the fluctuating nature of carrying capacity. Understanding these principles is crucial when studying population dynamics and anticipating the impacts of environmental changes on species populations.