Population Dynamics

The “Oh Deer!” activity during Wednesday’s biology class demonstrated the dynamic nature of population within an ecosystem. The activity was designed to simulate the impact on the deer population of a forest under different environmental conditions. The factors that affect the population of a species were broken down into density dependent and density independent factors. Density dependent factors are the factors in which the density of the species plays a significant role in shaping the population size of that species. Population independent factor on the other hand are factors that change the population with no correlation to the density of that particular species.

During the first part of the activity each student was assigned a role in the ecosystem as either a deer or a resource. At first the deer population is very tiny while the resources are abundant; no competition existed amongst the deer. As resources was consumed and more deer were born the resources starts to deplete and competition became increasingly intense. At a certain point the resources in the forest could not support the large population and deer died off and became resources for future deer. An equilibrium was reached where the resources is just enough to maintain the deer population. The competition for limited amount of resources is an example of density dependent factor in population dynamics. A few outside forces was introduced into the ecosystem such as flood, drought and other natural disasters. Each natural disaster was followed by a decline in the deer population. These factors are density independent factors.

In the second part of the activity predators were introduced into the ecosystem and the effect of predation on population was simulated. Similar to the relationship between the deer and forest resources, the wolves had little competition when the wolf population was small compared to the deer’s population and the competition escalated as less deer were available and more competitors entered the hunt.  This phenomenon is once again due to the density dependant factor of intraspecies competition. When the wolf population was not controlled and increased rapidly the deer population in that area was decimated and was eventually driven to extinction. In real life the deer would probably migrate somewhere else to avoid total annihilation, this phenomenon was also evident in our activity when some deer went off the grid to escape the wolves.