3 Factors affecting population growth

Two main groups:

• 1.
• Environmental factors. All living (biotic) and non-living (abiotic) components of the environment: food, water, temperature, disease, predators and space.

• When the environment is rich (plenty of resources), survival and reproduction increase and the population rises.
• When it deteriorates (scarcity, danger, pollution), the population decreases due to lower reproduction, higher death rate, or both.

• 2.
• Genetic factors. The inherited traits that affect an organism's ability to adapt, survive and reproduce.
• Individuals in a population are not identical; the genetic variation gives some a better chance in a given environment.
• Examples: fur colour, resistance to disease, tolerance of heat or cold, sharp eyesight, strong sense of smell, strong beaks for cracking seeds.

Classifying cases:

Resource abundance followed by scarcity: the population first increases, then, as resources run short, competition rises and the population falls until a balance with the available resources is reached.