Question

Describe three density-dependent factors that prevent populations from growing indefinitely. For full credit, you must fully explain how the factor is density-dependent. Of these factors, which do you feel will most limit the growth of the human world population? Explain.

Answer 1

density-dependent factors that prevent populations from growing indefinitely

in nature the making limiting factors that affect population size is the availability of food, spacer or shelter besides these there are other density-dependent factors that prevent populations from growing indefinitely: competition, predation, parasitism, and disease. These factors become noticeable when the population reaches and exceed the limit.

1. Competition as a density-dependent factor: A habitat can only support a limited number of organisms as it is limited by space and resource availability. When the population size increases, the competition also increases. Therefore, when the population becomes larger and crowded, organisms start competing with each other for food, water, space, light, etc. and other essential factors. For example, animals compete for food, water, shelter, nesting, space while plants compete for sunlight, nutrients, space.

2. Waste accumulation as a density-dependent factor: As the population density increases it leads to more accumulation of harmful waste products that cause the death of individuals, impair reproduction and reduces the population’s growth

3. Disease as a density-dependent factor: diseases tend to spread in densely packed populations as organisms are close to one another. Diseases are less likely to spread in sparse populations. However, the disease will not kill off its host population as it makes difficult for the diseases to survive.
4. Predation as a density-dependent factor: both predator and prey population is influenced by predation as a density-dependent factor. Consider the classic example of lion and deer: as the deer population rises, the lion has more to eat and thus its population increases. As a result, more predatory pressure is applied and causes a decline in the deer population. The drop in food availability drops the predator population.

Of all these density-dependent factors, the one that I think is likely to limit human population growth is waste accumulation. Human population has shown exponential growth and unchecked population growth will bring environmental catastrophe. As the population increased, there is a tremendous increase in the accumulation of harmful waste. As the health of our environment deteriorates, it is likely to cause a decline in the human population, causing the death of individuals due to decrease in potable water, fertile land, forests, etc.