Factors that Affect Population Growth

• Density-independent factor is an abiotic event that affects population growth in the same way, regardless of population density, examples include weather, floods, forest fires, and droughts.
• Density-dependent factor is a biotic interaction that varies in its effect on population growth, depending on the density of the populations involved, examples include competition, predation, and disease.
• Intraspecific competition is a situation in which members of the same population compete for resources, examples include trees in a forest that compete for light, nutrition, and water.
• Interspecific competition is a situation in which two or more populations (different species) compete for limited resources, examples include invasive species.
• Allee Effect occurs when a population cannot survive or fails to reproduce enough to overcome the mortality rate due to a low population density, this can produce an increased extinction risk, for example, the Great Auk.
• A population cycle refers to alternating periods of large and small population sizes, resulting in a sinusoidal growth pattern, which is a wavelike oscillating growth pattern that is typical of predator-prey interactions.
• Organisms have adapted to help protect themselves against predators, including protective colouration, camouflage, mimicry, and body colouration used as a warning signal.
• Symbiosis refers to an ecological relationship between two species living in direct contact, this includes parasitism, mutualism, and commensalism.
• Parasitism is when one partner benefits from the relationship while the other is harmed.
• Mutualism is when both partners benefit from the relationship or depend on each other to survive.
• Commensalism is when one partner benefits from the relationship while the other is unaffected.