Population growth decreases when the number of individuals in a population declines, and this primarily happens due to mortality and emigration.
Factors Leading to Decreased Population Growth
Here's a breakdown of the factors that reduce population growth:
Mortality
- Definition: Mortality refers to the number of deaths within a population. This is a key factor in reducing population size. The reference specifically mentions "mortality and emigration" as factors that cause a population to decrease.
- Death Rate: A high death rate contributes significantly to decreased population growth. The death rate is the number of individuals that die per 1,000 individuals in a population.
- Causes of High Mortality: Increased mortality can be caused by various factors such as:
- Disease outbreaks: Epidemics and pandemics can drastically reduce populations.
- Famine: Lack of access to food resources leads to starvation and death.
- Predation: High predation rates can diminish populations.
- Natural disasters: Events like floods, earthquakes, and wildfires can cause mass fatalities.
- Environmental degradation: Pollution and habitat loss contribute to increased mortality rates.
Emigration
- Definition: Emigration is when individuals leave a population to live in another location, reducing the population size.
- Reasons for Emigration: Emigration is often triggered by:
- Lack of resources: Individuals may leave if food or water is scarce.
- Poor living conditions: Overcrowding or environmental issues might drive emigration.
- Seeking better opportunities: Individuals might migrate in search of better employment, education, or quality of life.
- Conflict or violence: People might emigrate to escape war or persecution.
- Impact on Population Size: When people leave an area to live elsewhere, the population decreases. Emigration directly reduces the number of individuals within a specific population.
Summary
In summary, both mortality (deaths within the population) and emigration (individuals leaving the population) are primary factors that lead to a decrease in population growth. Understanding these factors is essential for analyzing and managing population dynamics.
