Energy pyramids: how much energy reaches each level
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Read this first
Use the table
Card (real data, from OpenStax Biology 2e). Biomass in the English Channel.
level biomass (g/m²) producers (phytoplankton) 4 primary consumers (zooplankton) 21 Jun reads real biomass data from the English Channel. Which statement about the pyramids is right?
- The biomass pyramid is upright here, and the energy pyramid is the inverted one
- Both pyramids are inverted here, since the primary consumers hold more than the producers
- Both pyramids are upright, since biomass must fall at each level of a chain
- The biomass pyramid is inverted here, but a pyramid of energy is upright
Kira reads the English Channel data again. How can 4 g/m² of producers support 21 g/m² of primary consumers?
- Energy passes up with no loss, so a higher level can hold more than the one below
- The primary consumers make their own energy from light, so they need few producers
- The primary consumers send their energy back to the producers each day to use again
- The phytoplankton reproduce quickly, so the small mass is replaced fast
Luz reads real counts for a temperate forest. Why can 200 trees support 150,000 primary consumers?
- Energy grows at each step, so the insects hold more energy than the trees below them
- Each tree holds very little energy, so a few trees could support just a few insects
- Large trees capture a lot of energy, so a few can support many small organisms
- The insects send their energy back to the trees, who use it again to grow
Energy pyramid (real data, from OpenStax Biology 2e), not to scale, 4 steps from the bottom. Unit: kcal/m²/yr. Milo compares Silver Springs with the 10 percent rule of thumb. Which statement fits the three steps?
- Each step passes a larger percent than the step before it, rising up the pyramid
- The first two steps pass more than 10 percent and the third passes less
- The three steps each pass less than 10 percent, so the rule of thumb is too high
- The three steps each pass exactly 10 percent, so the rule of thumb matches the data
Use the table
Card (real data, from OpenStax Biology 2e). The first step at Silver Springs.
measure percent passed up TLTE given by OpenStax about 14.48 from the pyramid numbers 3,368 and 20,810 about 16.2 Pia reads two values for the first step at Silver Springs. Which statement is best?
- The values are close but not equal, and both are above 10 percent
- The 16.2 must be wrong, since TLTE is a fixed value of 14.48 percent
- Together they show that exactly 10 percent of the energy passes up the pyramid
- TLTE is the percent of the energy that is lost as heat at the first step
Use this
Energy pyramid (real data, from OpenStax Biology 2e), not to scale, 4 steps from the bottom. Unit: kcal/m²/yr. Bottom step: producers (plants), 20,810. Second step: primary consumers, 3,368. Third step: secondary consumers, 383. Top step: tertiary consumers, 21. Notebook, 3 lines. Line 1: The producers hold 20,810 and the primary consumers hold 3,368, in kcal/m²/yr. Line 2: 3,368 divided by 20,810 is about 16.2 percent. Line 3: So exactly 10 percent must pass up in every ecosystem, and 16.2 is a mistake.
Tala reads a notebook entry about Silver Springs. Which line has a flaw?
- Line 2: the percent should be found by dividing 20,810 by 3,368
- No line has a flaw, since 16.2 percent rounds to 10 percent
- Line 1: the primary consumers should hold more energy than the producers do
- Line 3: 16.2 is not 10, so the rule is a rough guide, not exact
Use this
Energy pyramid (model data), not to scale, 3 steps from the bottom. Unit: kJ. Bottom step: producers (grass), 10,000 kJ. Second step: primary consumers (grasshoppers), 1,000 kJ. Top step: secondary consumers, 100 kJ. Decomposers break down the wastes and remains from the levels. Notebook, 3 lines. Line 1: Producers pass energy to the primary consumers. Line 2: Decomposers break down remains and return matter to the soil. Line 3: They also return the energy, so energy is reused like matter.
Zee reads a notebook entry about decomposers. Which line has a flaw?
- Line 1: producers do not pass any energy on to the primary consumers
- Line 3: matter returns, but energy leaves as heat and is not reused
- No line has a flaw, since energy is reused like matter in an ecosystem
- Line 2: decomposers do not return any matter to the soil or the ecosystem
Use this
Energy pyramid (model data), not to scale, 4 steps from the bottom. Unit: kJ. Bottom step: producers (grass), 10,000 kJ. Second step: primary consumers (grasshoppers), 1,000 kJ. Third step: secondary consumers, 100 kJ. Top step: tertiary consumers, 10 kJ.
Ari's friend says the top level holds the most energy because it is at the top. Which reply is best?
- Disagree: each step up holds less, since heat is lost at each step
- Disagree: the middle steps hold the most energy, with less at the top and bottom
- Agree: energy builds up as it passes up each step, so the top holds the most
- Disagree: the four steps hold equal energy, since nothing is lost on the way up
Bo's friend says a food chain could have any number of levels if the sun keeps shining. Which reply is best?
- Agree: decomposers return energy to the top level, so it can be reused
- Disagree: the energy is destroyed at the top level, which ends the chain
- Agree: energy passes up unchanged, so any number of levels can be supported
- Disagree: heat is lost at each step, so a long chain runs out of energy
Energy pyramid (real data, from OpenStax Biology 2e), not to scale, 4 steps from the bottom. Unit: kcal/m²/yr. Esme's friend says the 10 percent rule means exactly 10 percent passes up in every real ecosystem. Which reply is best?
- Disagree: the real percents are higher than 10 at the first step and at each step after
- Agree: Silver Springs passes about 10 percent at the first step and at each step after
- Agree: a real food chain passes the same percent from one step to the next
- Disagree: it is a rough guide; Silver Springs passes 16.2, 11.4 and 5.5 percent