AP Biology Unit 8: Ecology

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What is net primary productivity (NPP)?

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NPP is the amount of energy available for trophic levels above producers, calculated as the total solar energy converted to chemical energy by producers minus the energy used in respiration.

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What are pioneer species?

Back

Pioneer species are the first organisms to colonize previously disrupted or damaged ecosystems, such as mosses and lichens in primary succession.

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What does a stable population pyramid indicate?

Back

A stable population pyramid indicates that the population is in a steady state, with birth rates and death rates balanced.

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What is species richness?

Back

Species richness is a measure of the number of different species living in an ecosystem, indicating the amount of biodiversity.

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What are density-dependent factors?

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Density-dependent factors are factors that limit population growth based on the population density, such as predation, food competition, and birthrate.

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What is the difference between primary and secondary succession?

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Primary succession occurs in lifeless areas where soil has not yet formed, while secondary succession occurs in areas where a disturbance has destroyed an existing ecosystem but soil and some organisms still remain.

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What is biodiversity?

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Biodiversity refers to the variety of life in a particular habitat or ecosystem, including the number of species, genetic diversity, and ecosystem diversity.

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What role do producers play in an ecosystem?

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Producers, such as plants and algae, convert solar energy into chemical energy through photosynthesis, forming the base of the food web.

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What is a trophic level?

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A trophic level is a position in a food chain or food web, defined by how organisms obtain energy, such as producers, primary consumers, and secondary consumers.

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What is the significance of keystone species?

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Keystone species are species that have a disproportionately large effect on their environment relative to their abundance, playing a critical role in maintaining the structure of an ecosystem.