Answer:
When the number of organisms in an ecosystem exceeds the carrying capacity, the population will decrease.
Please see the explanation!
Step-by-step explanation:
The maximum that can be maintained forever is the concept of "carrying capacity." This can only be rationally understood as the highest number that can be maintained using exclusively renewable resources. It can only be exceeded by using resources more quickly than they can be replenished.
The population gets wiped out (not by old age mortality) back to the number that can be maintained using only renewable resources when those resources become limited, as they must by definition.
Remember that every population is trying to expand, therefore if a species finds a resource that it can use more quickly than it replenishes, the population will undoubtedly expand to use that newly discovered capability. Another way to put this is to say that when the species average is x newborns and the subsistence supply is steady, (x-2)/x children must perish. Less offspring must perish than the formula predicts when the species finds a new non-renewable source of food, increasing the subsistence supply.
It should be noted that there are plainly too many people in the world. Over the past few hundred years, we have developed various technologies that have increased subsistence extraction and decreased waste. Of course, we have multiplied to occupy that additional space. In order to provide enough food to sustain 7+ billion people at once, we need fossil fuels and a number of other resources that do not replenish as quickly as we use them. The last time humanity were able to maintain their population on exclusively renewable resources, there were less than 1 billion people. Be aware that we have never been able to raise subsistence production as quickly as we have sought to increase our population. We have always had an average of too many infants, as seen by the starvation-related child mortality that affects some populations.
Thank you,
Eddie