BLY 122 ch. 46

What can Antarctic ice core samples tell us about atmospheric CO2 levels? Select all that apply.

- CO2 ice core data confirm CO2 measurements taken directly from the atmosphere. - Ice cores can help scientists estimate atmospheric CO2 levels from hundreds of thousands of years ago.

Because energy transfer is not 100% efficient across trophic levels, an average of about _____ of energy and biomass available at one trophic level is available at the next.

10%

Which of the statements is an accurate reflection of photosynthesis and chemical weathering?

Both processes use CO2 as a reactant; that is, they decrease atmospheric CO2 levels.

Which of the equations is the chemical reaction for cellular respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O

How can scientists distinguish among different sources of CO2 in the atmosphere?

The amount of different carbon isotopes in the CO2 differs based on the source.

Which of these organisms is considered a primary consumer?

a grasshopper

A community of organisms and the physical environment it occupies are known together as a(n):

ecosystem

A _____ takes into account the diverse interactions between primary producers, consumers, and decomposers. It depicts the flow of carbon through an environment as interdependent of primary producers, consumers, and decomposers.

food web

A _____ depicts the flow of carbon through an ecosystem, whereas a _____ depicts the transfer of energy.

food web; trophic pyramid

To some extent, Earth's surface reflects solar radiation (in the form of heat), which is subsequently absorbed by certain _____ gases in the atmosphere, such as methane and CO2.

greenhouse

Recall that in the northern hemisphere, atmospheric CO2 levels are highest in early spring and lowest in early fall. What accounts for this seasonal fluctuation in atmospheric CO2 levels?

photosynthesis

The movement of Earth's crust, plate tectonics, contributes to the long-term carbon cycle through all of the answer choices except:

photosynthesis

Recall that during the Paleozoic Era, atmospheric CO2 levels decreased. Why?

photosynthetic, woody plants first appeared during this period

Cyanobacteria, milkweed plants, and oak trees are all considered:

primary producers

Which of these organisms can incorporate atmospheric carbon directly into C6H12O6, thereby playing a major role in a food web?

primary producers

Decomposers are vital components of a food web because they:

return carbon (as CO2) to the atmosphere

Photosynthesis and respiration both play a major role in the _____ carbon cycle and can affect atmospheric CO2 levels on a seasonal or annual basis.

short-term

Which of the answer choices are reservoirs of carbon? Select all that apply.

soil, oceans, organisms, the atmosphere

Which of the processes is responsible for the change scientists observed in atmospheric concentrations of 12C, 13C, and 14C over the last 200 years?

the burning of fossil fuels

Over the last several decades, what have researchers discovered about atmospheric CO2 levels?

they have increased