Limits to Growth

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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 environmental factor that controls the growth of a population, determining its carrying capacity.

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Example: This diagram shows a chemical reaction where hydrogen (H₂) is the limiting factor. The reaction stops when all the hydrogen is used, leaving extra oxygen (O₂) unused.

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Carrying Capacity Noun

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

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Carrying Capacity

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The maximum number of individuals of a particular species that a specific environment can sustainably support over time.

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Example: This diagram uses a bucket to represent an environment's carrying capacity. Population increases from reproduction (inflow) while limiting factors like disease and predators (outflows) remove individuals.

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Density-Dependent Limiting Factor Noun

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[den-si-tee di-pen-dent lim-it-ing fak-ter]

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Density-Dependent Limiting Factor

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A limiting factor that operates strongly only when population density reaches a certain level, such as competition or disease.

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Example: As the number of individuals (hands) increases, the competition for a limited resource (bread) becomes more intense, limiting the amount available for each one.

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Density-Independent Limiting Factor Noun

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

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Density-Independent Limiting Factor

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A limiting factor, such as a natural disaster, that affects all populations in similar ways, regardless of their size and density.

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Example: A drop in temperature, an abiotic factor, can limit a mosquito population, regardless of how many mosquitoes there are.

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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 population size per unit area, indicating how crowded a population is in its habitat.

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Example: This diagram shows how an environmental factor affects a population's density. The highest density (most rabbits) is in the 'Optimum' zone, decreasing in 'Stress' zones.

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Competition Noun

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[kom-pi-tish-uhn]

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Competition

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An interaction where organisms or species vie for the same limited resources, such as food, water, or territory.

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Example: This diagram shows two types of competition for resources: intraspecific (within a species) and interspecific (between different species), which can limit population growth.

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Predation Noun

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[pri-dey-shuhn]

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Predation

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A biological interaction where one organism, the predator, hunts, captures, and feeds on another organism, the prey.

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Example: A chameleon (predator) uses its long, fast tongue to catch an insect (prey), showing how one organism hunts another for food.

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Herbivory Noun

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[hur-biv-uh-ree]

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Herbivory

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A biological interaction in which an animal, known as an herbivore, consumes plants as its primary food source.

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Example: This diagram shows that herbivores, like the deer, are animals that get their energy by eating producers, like grass.

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Parasitism Noun

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[par-uh-si-tiz-uhm]

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Parasitism

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A symbiotic relationship where one organism, the parasite, lives on or inside another organism, the host, causing it harm.

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Example: This diagram shows a tick's life cycle, where it must feed on hosts like deer and humans to grow and reproduce, demonstrating a parasitic relationship.

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Extinction Noun

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[ik-stingk-shuhn]

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Extinction

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The process by which a species, family, or other group of organisms ceases to exist entirely.

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Example: This collapsing tower shows how removing key parts of an ecosystem or population makes it unstable, eventually leading to a total collapse, which represents extinction.