7.2 Biodiversity Loss and Extinction

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What is background extinction?

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The extinction of a species one by one, rather than a sudden loss of many species.

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What does it mean when a species is classified as 'threatened'?

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It means they are likely to become endangered.

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How many mass extinctions have occurred on Earth?

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There have been 5 mass extinctions.

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Approximately how long ago did dinosaurs become extinct?

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Dinosaurs became extinct about 65 million years ago.

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What is the primary source of knowledge about early life on Earth?

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Most of what we know of early life comes from fossils.

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What is mass extinction?

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A rapid and widespread decrease in the biodiversity on Earth, resulting in the extinction of a large number of species in a relatively short period.

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What is the difference between background extinction and mass extinction?

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Background extinction occurs gradually over time, while mass extinction happens suddenly and affects a large number of species.

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What factors can lead to species becoming endangered?

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Habitat loss, climate change, pollution, overfishing, and invasive species.

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What is biodiversity?

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The variety of life in the world or in a particular habitat or ecosystem.

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Why is biodiversity important?

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Biodiversity contributes to ecosystem services, resilience, and overall health of the planet.