This is the Brown Bear population in Alaska. At the beginning of the graph, the population is increasing slightly, because the have just enough resources to survive. Also, they have a low population so not many babies can be produced. But, as the population grows, they start reproducing more and they have a enough resources available to sustain a larger population. But as the population starts to even out, they reach their carrying capacity. This means that the environment they live in has reached the maximum amount of the bear population with the available resources. If the population of fish were to go down, then the brown bear population would go down because they would have to compete for their main source of food.
Brown Bear feeding on its main source of food.
There are multiple ways that can influence the population of Brown Bears. One way is immigration, which is when bears come into the population. Bears can join other populations because they may want to go to a place where there is more food available. Also, bears can emigrate. This means that they can leave their population, causing that population to reduce. Another way that the bears population can be influenced is by the death rate of the bears. If there is limited resources, some bears will not survive because they cannot get food. One last way that the bears population can be influenced is by the birth rate. If the bears population has a plentiful amount of resources and no competition, then the bears can reproduce and cause the population to increase.
Two density dependent factors that could alter the population size are intraspecific competition with other Brown Bears, and disease. Competition with other bears in the area cause some of them to be short of food causing them to not make it to reproductive age to multiply and for them to die off earlier. Diseases can be spread throughout the fish population, the main source of food for brown bears, which is then eaten by the bears and spread throughout the population again killing the bears and limiting them from reproducing.
Two density independent factors that can change the population are temperature changes and storms. If the temperature drops down more than usual it could cause the fish to go down further into the water where it is warming making it harder for the bears to get the food necessary to survive. If storms where to happen, then a mix very cold temperatures and possibly blizzards and other dangerous storms could make i harder for the bear population to live and find food in the heavy sowed area.