Final answer:
A population reaches its carrying capacity when the growth rate levels off and the population size remains stable due to limited resources. This represents the maximum number of individuals the environment can sustain without ecological degradation.
Step-by-step explanation:
A population has reached the carrying capacity when successive generations show no further improvement. The carrying capacity is the maximum population size that a particular environment can support, considering the availability of resources such as food, water, and space, as well as other ecological limiting factors. When a population reaches its carrying capacity, it levels off because the birth and death rates become stable, leading to an equilibrium where the population size does not increase significantly.
In situations of overpopulation, the condition in which the population size exceeds the capacity of the environment to provide for its needs, populations may experience resource shortages, increased disease transmission, and potential conflict or violence. Conversely, factors like technological advancements and improved resource distribution can sometimes increase the carrying capacity. However, there is a limit to this growth, and eventually, even with reduced consumption and better distribution, the total population may have to stop growing when the carrying capacity is reached.