Which of the following is an abiotic factor that may limit population growth?

Population biology is a field of study that explores populations and how they interact with their environment. Scientists observe all factors influencing a population within an ecosystem when gathering data about specific populations of interest. Often these observations are vital to decisions made about how to protect a species.

Environmental factors

Environmental factors that influence populations are divided into two categories – abiotic and biotic factors. Abiotic factors refer to the non-living physical and chemical elements found in an ecosystem such as rainfall, temperature, pH, sunlight, shelter and day length. Biotic factors refer to the living or once-living organisms in an ecosystem and their impacts such as predation, competition, food supply, human impacts and parasites.

Environmental factors such as rainfall, climate, predators, shelter and food availability can change. Often, these factors play an important role in the survival of populations. Some factors change from day to day or season to season. Some, like food availability and predation, may vary over several years. A species that successfully survives in an environment has adapted to tolerate any minimal or seasonal fluctuations in these factors.

For each factor, there is an optimum range where a species will thrive. If conditions change, organisms that can will move to live within the optimal conditions for survival.

On either side of the optimum range, conditions can become difficult. This is referred to as a stress zone. Beyond the stress zone is the zone of intolerance. In this zone, individuals – and entire populations – may die.

Most environments have one factor that determines the distribution of a species. This is known as Liebig’s law of the minimum. This critical factor is called the limiting factor. For aquatic species, it may be water temperature or tidal exposure. For birds like the takahē, it could be food availability.

The functioning of an organism is limited by the essential environmental factor that is present in the least favourable amount.

Liebig’s law of the minimumn

Interspecific relationships are a biotic factor that describe the interactions between organisms within their environment. These interactions may have negative, positive or neutral effects on either species’ ability to survive and reproduce. The major types of species interactions are predation, competition, parasitism, mutualism, commensalism and amensalism.

Populations dynamics

All the organisms of the same species found in a particular region are called a population. The distribution of a population is determined by limiting factors. A population can vary in density (number of individuals in a population), distribution (the size of the population’s area and how the population is spread out in this area) and age structure.

Populations change over time. Natality (birth rate) and mortality (death rate) are two aspects that control the age structure of a population. The relationship between the two aspects can be plotted on a survivorship curve.

Individuals can also migrate to other groups or start new groups, and this can lead to changes in the genetic make-up of populations. Genetic drift can cause big losses of genetic variation for small populations. Reduced genetic variation can impact the ability for the population to be able to adapt to new selection pressures such as changes in available resources or other abiotic and biotic factors.

Changes to allele frequencies in populations can have dramatic effects such as bottleneck and founder effects. For takahē, the rapid decline of the population meant that the gene pool is limited to the few individuals that survived and reestablished the population.

Limiting factors are those things in an ecosystem that restrict the size, growth, and/or distribution of a population. Biotic or biological limiting factors are things like food, availability of mates, disease, and predators. Abiotic or physical limiting factors are non-living things such as temperature, wind, climate, sunlight, rainfall, soil composition, natural disasters, and pollution.

Carrying Capacity

The population size of a species that can be supported by an ecosystem is called its carrying capacity. When populations increase in size, there is a greater demand for resources which increases competition. Natural selection comes into play and the individuals who are the most capable of competing and adapting will survive while the others die out. This is one of many natural feedback loops that help control the size of populations.
Limiting factors are further subdivided into two categories related to the density of the population—density dependent factors and density independent factors.

Density Dependent Factors

Some abiotic limiting factors affect members of a population because of the population density. These things include disease, food supply, and increased predation. Diseases and parasites are more easily transmitted in larger populations. More individuals mean increased competition for the food that is available. In addition, larger populations attract more predators who seek out individuals that are weak, injured, or diseased.

Density Independent Factors

Other limiting factors affect populations regardless of its density such as drought, floods, earthquakes, human activity, fires, and pesticides. Density independent factors are often abrupt and can kill all members of smaller populations.

Some Abiotic Factors are Unique to Ecosystems

All organisms need food to survive, so this biotic limiting factor is common to all ecosystems. Other environments like freshwater biomes, the desert, tropical rainforests, and the arctic tundra have biotic limiting factors that are unique to that area. For example, arctic foxes and polar bears are unique predators on the arctic tundra. Also, scorpions and cacti are biotic limiting factors in the desert that are not present on the arctic tundra.

What is an abiotic factor that can limit population growth?

Which of the following is an abiotic factor that may limit population growth quizlet?

What are the factors that limit population growth?

Which of the following is a biotic factor that limits the growth of a population in aquatic ecosystems?