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Course: AP®︎/College Environmental science > Unit 1

Lesson 3: Matter and energy flow
Science
AP®︎/College Environmental science
The living world: ecosystems and biodiversity
Matter and energy flow
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Matter and energy flow

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Problem

Suppose that in the food chain shown below, 3,000kcal is available at the secondary consumer level.
Four organisms are arranged in four different vertical levels. On the bottom level is green algae, a producer. An arrow from the algae points up to the second level. The second level shows calanoids, which are primary consumers. An arrow from calanoids points up to the third level where an American eel is shown as a secondary consumer. An arrow from the eel points to a Chinook salmon, which is a tertiary consumer at the top level of the diagram.
Based on the 10% rule of energy transfer, how much energy is available at the level of the green algae?
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi
kcal