Populations and Abiotic Factors

Populations and Abiotic Factors


  • A population refers to a group of organisms of the same species living in a particular area and interacting within their environment.

  • Population size can be determined by birth rate (natality), death rate (mortality), immigration (movement into an area) and emigration (movement out of an area).

  • The distribution of a population is affected by abiotic factors, biotic factors, and the interactions between members of the population.

  • Random distribution tends to occur in environments where resources are plentiful and evenly distributed, with no competition between individuals or predators.

  • Uniform distribution is characterised by individuals spaced evenly across the environment. It may occur due to competition for resources or social interactions.

  • Clumped distribution occurs when individuals group together in certain parts of their environment. This pattern can occur due to resource availability or group behaviour.

Abiotic Factors Influencing Populations

  • Light intensity affects the distribution of photosynthetic organisms. Areas with high light intensity can support larger populations of these species due to increased photosynthetic rates, leading to greater food production.

  • Temperature can directly affect the survival and distribution of a species. Some species are adapted to thrive in specific temperature ranges and will form larger populations in these areas.

  • Water availability has a profound effect on population distribution. Species that require large amounts of water, for example, will be more abundant in areas where water is readily available.

  • Oxygen concentration significantly impacts animal populations. Aquatic organisms, for example, are often distributed based on the level of dissolved oxygen in their environment.

  • Soil type can influence the distribution of plant populations. Some plants are adapted to grow better in certain soil types due to the availability of specific nutrients or pH levels.

Population Responses to Abiotic Factors

  • Organisms respond to changes in abiotic factors by adapting, moving, or altering their behaviour to increase their chances of survival.

  • Physical adaptations, such as the thickness of fur in mammals or the type of roots in plants, can influence how well a species can survive in its environment.

  • When faced with unfavourable abiotic conditions, animals might migrate to areas with more favourable conditions, this can happen both on a seasonal and temporary basis.

  • Animals can also undergo behavioural changes in response to abiotic factors. For instance, during a drought, some animals might become nocturnal to reduce water loss.