Population Growth

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Population Noun

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[pop-yuh-ley-shuhn]

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Population

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The total number of organisms of the same species that live in a specific geographical area at the same time.

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Example: This diagram shows a large group of individuals defined as the 'Population,' from which a smaller 'Sample' group is selected for study.

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Immigration Noun

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[im-i-grey-shuhn]

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Immigration

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The process of individuals moving into a population from another area, which increases the population's size.

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Example: This historical photo shows immigrants arriving at Ellis Island. Immigration is the movement of individuals into a population, causing it to increase in size.

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Emigration Noun

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[em-i-grey-shuhn]

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Emigration

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The process of individuals moving out of a population to another area, which decreases the population's size.

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Example: This diagram shows that emigration, the movement of individuals out of a population, is a factor that causes the population's size to decrease.

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Birth Rate Noun

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[burth reyt]

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Birth Rate

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The number of live births per unit of time, often expressed per 1,000 individuals in a given population.

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Example: This chart shows the percentage of new mothers in 2011 based on their education level, not the scientific concept of birth rate (births per 1,000 people).

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Death Rate Noun

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[deth reyt]

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Death Rate

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The number of deaths per unit of time, also called mortality, often expressed per 1,000 individuals in a population.

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Example: This chart shows that a population's total deaths are composed of different causes, such as various diseases, each contributing a certain percentage to the overall mortality.

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Population growth rate Noun

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[pop-yuh-ley-shuhn grohth reyt]

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Population growth rate

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The rate at which the number of individuals in a population increases or decreases during a given period of time.

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Example: This graph shows how the human population grew slowly for thousands of years and then increased very rapidly, demonstrating a dramatic change in the population growth rate.

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Exponential growth Noun

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[ek-spoh-nen-shuhl grohth]

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Exponential growth

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A pattern of rapid population increase that occurs when resources are abundant, often represented by a J-shaped curve.

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Example: This graph shows that as time passes, a population's size increases at a faster and faster rate, creating a characteristic J-shaped curve.

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Logistic growth Noun

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[loh-jis-tik grohth]

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Logistic growth

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A growth pattern that slows and levels off as a population approaches carrying capacity due to limited resources.

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Example: This graph shows how a population's size increases slowly, then rapidly, and finally levels off as it reaches the environment's carrying capacity.

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Limiting factors Noun

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[lim-i-ting fak-terz]

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Limiting factors

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Environmental conditions such as resource availability and disease that prevent a population from growing indefinitely.

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Example: This diagram shows a bucket overflowing to represent a population. The labeled streams leaving the bucket, like 'predators' and 'disease,' are limiting factors.

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Carrying capacity Noun

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[kar-ee-ing kuh-pas-i-tee]

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Carrying capacity

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The largest number of individuals of a particular species that an ecosystem can sustainably support over a long period.

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Example: This graph shows that a population's growth slows and stops when it reaches the carrying capacity, the maximum number the environment can support.