Population Density

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Population Ecology Noun

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[pop-yuh-ley-shuhn ee-kol-uh-jee]

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Population Ecology

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The scientific study of populations and how they interact with their environment, focusing on size, density, and distribution.

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Example: This diagram shows how an environmental factor affects a population's density. Most rabbits live in the optimal zone, with fewer in stress zones.

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Population Density Noun

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[pop-yuh-ley-shuhn den-si-tee]

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Population Density

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A measurement of the number of individuals of a particular species living per unit of area or volume.

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Example: This map shows population density by using colors to represent the number of people per square mile, from sparse green areas to dense red cities.

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Immigration Noun

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[im-i-grey-shuhn]

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Immigration

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The movement of individuals into a specific population's area from another location, which increases the population size.

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Example: This historical photo shows a large group of immigrants arriving at a processing center, illustrating how the movement of people into a new area increases its population.

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Emigration Noun

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[em-i-grey-shuhn]

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Emigration

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The movement of individuals out of a specific population's area to another location, which decreases the population size.

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Example: This diagram shows emigration as deer leave the western population, moving through a mountain pass. This movement out of an area decreases its population.

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Limiting Factor Noun

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[lim-it-ing fak-ter]

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Limiting Factor

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Any biotic or abiotic factor that restricts the size, growth, reproduction, or distribution of a population in an ecosystem.

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Example: An environment can only support a certain population size (the bucket's capacity). Factors like disease and predators are limiting factors that remove excess individuals.

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Density-Dependent Factor Noun

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[den-si-tee di-pen-dent fak-ter]

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Density-Dependent Factor

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A limiting factor whose effect on a population is related to the number of individuals in a given area.

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Example: This graph shows how the predator population changes in response to the prey population's density, a key example of a density-dependent factor.

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Density-Independent Factor Noun

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[den-si-tee in-di-pen-dent fak-ter]

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Density-Independent Factor

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A limiting factor that affects a population's size and growth regardless of the population's density.

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Example: This graph shows birth rate decreasing as population grows. This is a density-dependent factor, the opposite of a density-independent factor.

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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 maximum population size that a particular environment can consistently support with its available resources over a long period.

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Example: This graph shows a population's S-shaped growth over time, leveling off at the 'Carrying Capacity,' the maximum number of individuals the environment can support.

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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 in which the growth rate is proportional to the size of the population.

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Example: This graph shows that as time passes, the population 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 pattern of population growth that starts rapidly, slows as it approaches the carrying capacity, and then levels off.

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Example: This graph shows how a population grows over time, starting slow, then fast, and finally leveling off as it reaches the environment's 'carrying capacity'.