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Biodiversity: Test Your Understanding
Teacher's Guide
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ward
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1. Most researchers estimate the total number of species in the world to range from 3 to 30 million. Why do
some researchers hypothesize that this number may be orders of magnitude higher?
Species that live in the ocean and in soils remain largely unknown. The ocean is extremely deep in parts
and difficult to physically explore. Similarly, soil horizons extend deep into the ground and can vary
dramatically, even within a single ecosystem.
2. Why is species biodiversity important to human endeavors?
Sample answer: Biodiversity largely impacts the type of resources available for human use, including
food, energy, and medicinal constituents.
3. Critical Thinking: Would you categorize humans as a keystone or redundant species? Why?
Sample answer: Humans would most likely be considered a keystone species, in that if they were
removed from the ecosystem, it would change dramatically.
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