But, bacterial generation time is much faster than that of a blue whale, even though they both can grow exponentially. As populations increase, resources dwindle, predation increases, birth rates decline, and death rates increase. Each environment and population has its carrying capacity, or the maximum number of individuals supported over the long term. But its not that easy.
Wild populations tend to grow and crash, rather than show steady population numbers.
The wolf population crashed around 1980, due to canine parvovirus. The moose population increased, then crashed when they overgrazed their food resources. The moose need the wolves. Can exploit unstable environments. Are competitive in stable environments.