What are biotic factors that affect population growth?

Biotic factors that affect population growth include competition, predation, symbiosis, disease, and food availability.

Biotic factors are living or once-living organisms in the ecosystem that can influence the growth of a population. One of the most significant biotic factors is competition. This can occur within a species (intraspecific competition) or between different species (interspecific competition). For example, two species of birds might compete for the same type of food or nesting sites. The species that is better adapted to these conditions will likely have a higher population growth rate.

Predation is another biotic factor. Predators can control the population of their prey, preventing it from becoming too large. If the number of predators decreases, the prey population might increase rapidly, but if there are too many predators, the prey population could decrease. This relationship between predators and prey is a delicate balance and can significantly impact population growth.

Symbiosis, the interaction between two different organisms living in close physical association, can also affect population growth. This includes mutualism (where both organisms benefit), commensalism (one organism benefits, the other is unaffected), and parasitism (one organism benefits at the expense of the other). For instance, parasites can limit population growth by causing disease or death.

Disease is a significant biotic factor as well. Pathogens can spread quickly through a population, especially if individuals are living in close proximity. This can lead to a rapid decrease in population size. On the other hand, a population with a strong immune response to a particular disease may have a competitive advantage, leading to increased population growth.

Lastly, food availability is a crucial biotic factor. If a population's food source is abundant, the population may grow. However, if the food source becomes scarce, the population may decrease due to starvation. This is often seen in predator-prey relationships, where a decrease in the prey population can lead to a decrease in the predator population.