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9.6: Review

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    After completing this chapter you should be able to...

    • Define biodiversity.
    • Distinguish among ecosystem, species, and genetic diversity, explaining the value of each.
    • Define and provide examples of ecosystem services.
    • Distinguish between species richness and species evenness.
    • Provide an approximate estimate of the number of species on Earth as well as the percentage of species that have been identified.
    • Explain the criteria for biodiversity hotspots and their role in conservation.
    • Identify the characteristics of endemic species.
    • Summarize hypotheses explaining high biodiversity near the equator.

    Biodiversity exists at multiple levels of organization and is measured in different ways depending on the goals of those taking the measurements. These measurements include ecosystem diversity, species diversity, and genetic diversity. The number of described species is estimated to be 1.5 million with about 17,000 new species being described each year. Estimates for the total number of species on Earth vary but are on the order of 10 million. Biodiversity is negatively correlated with latitude for most taxa, meaning that biodiversity is higher in the tropics. The mechanism for this pattern is not known with certainty, but several plausible hypotheses have been advanced.


    Modified by Melissa Ha from Conservation & Biodiversity from Environmental Biology by Matthew R. Fisher (licensed under CC-BY)

    This page titled 9.6: Review is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by Melissa Ha and Rachel Schleiger (ASCCC Open Educational Resources Initiative) .