ch 46 learning curve

Which of the answer choices is a reservoir of carbon?

- soil - the atmosphere - oceans - organisms - All of these choices are correct.

Which of the statements is true regarding atmospheric CO2 levels during the last 400,000 years?

Atmospheric CO2 levels fluctuate periodically, with the highest levels occurring during interglacial periods.

Imagine that a researcher has discovered a leaf fossil from the Cambrian Period that is 500 million years old. He notices that the leaf had very few stomata compared to present-day leaves. What does this tell the researcher about atmospheric CO2 levels during the Cambrian Period?

Atmospheric CO2 levels were higher during the Cambrian Period than today.

A researcher is measuring Earth's atmospheric CO2 levels, gathering data on CO2 levels in northern and then southern hemispheres. What do you expect that she will find?

Because atmospheric CO2 measurements represent global amounts, measurements in the Northern Hemisphere and Southern Hemisphere will be approximately the same.

The majority of carbon stored in abiotic reservoirs is in the form of:

CaCO3

Which of the statements is true regarding chemical weathering?

It contributes to the accumulation of CaCO3 in oceans.

Which of the answer choices is a form of nitrogen that can be utilized by plants?

NO3-

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

Photosynthetic, woody plants first appeared during this period.

Which of the statements is true regarding subduction?

The carbon it removes is eventually returned to the atmosphere by volcanism.

Which of these organisms is considered a primary consumer?

a grasshopper

Recall that photosynthetic rates remain relatively constant in regions near the equator. Imagine that tropical environments persist throughout Earth's northern and southern hemispheres; that is, that Earth's entire climate mirrors that near the equator. If Keeling had collected his atmospheric CO2 data on such an Earth, what would you expect the Keeling Curve to look like?

a straight line sloping upward, indicating that atmospheric CO2 levels would not seasonally oscillate, but would increase over time

Which of the answer choices would not be expected to affect primary production?

biomass of primary consumers

A scientist studying a material has determined that 12C, 13C, and 14C occur in the material in a ratio of 1000:10:1. How did he most likely differentiate between these forms of carbon?

by the number of neutrons in 12C, 13C, and 14C

The observation that atmospheric CO2 levels were typically low during glacial periods in Earth's history is an example of:

correlation.

Which group in a food web is responsible for returning inorganic compounds back to the environment?

decomposers

Hans Suess's work (and subsequent studies carried out by other researchers) determined that the amount of 13C in Earth's atmosphere has _____ and the amount of 14C in the atmosphere has _____.

decreased; also decreased

Nearly 150 years ago, man-made CO2 was introduced into the atmosphere primarily through _____. Currently, _____ is the main contributing factor to increased levels of human-produced CO2 in the atmosphere.

deforestation; the burning of fossil fuels

In terrestrial ecosystems, nitrogen is returned to the atmosphere by:

denitrifying bacteria.

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

ecosystem

Examining the relationship between primary producers, primary consumers, and secondary consumers is one way to track the flow of _____ through a system.

energy contained in organic compounds

In marine ecosystems, phosphorus is added to the ecosystem primarily from:

erosion of rocks on land.

Currently, atmospheric CO2 levels are the highest they have ever been in Earth's 4.6 billion-year history.

false

The rate of exchange of carbon between the atmosphere and the oceans represents a carbon:

flux

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

Nutrient cycling through ecosystems can be depicted using a(n):

food web.

Which of these relationships best depicts the amount of carbon stored in the atmosphere, sedimentary rocks, living organisms, and soil?

living organisms < the atmosphere < soil < sedimentary rocks

Which biogeochemical cycle does not include oxidation and reduction reactions that provide energy to microorganisms?

phosphorus

Which of the answer choices are not geological processes that drive the long-term carbon cycle?

photosynthesis and respiration

The equation 6CO2 + 6H2O → C6H12O6 + 6O2 represents the process of:

photosynthesis.

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

photosynthesis.

A heterotrophic organism that consumes primary consumers is called a(n):

predator

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

primary producers

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

primary producers.

The equation C6H12O6 + 6O2 → 6CO2 + 6H2O represents the process of:

respiration.

Energy flow through ecosystems can be depicted using a(n):

trophic pyramid

Phosphorus released from sedimentary rocks through chemical weathering can be immediately assimilated by primary producers and contributes to the biomass of primary producers in an ecosystem.

true

Primary consumers obtain carbon, nitrogen, and phosphorus through ingestion of primary producers.

true

The long-term and short-term carbon cycles are connected by the fact that some of the carbon contained in C6H12O6 (or other organic molecules) in plants is incorporated into sedimentary rocks or oil; carbon in sedimentary rock and oil is not immediately cycled back to the atmosphere.

true

The carbon and nitrogen cycles are related to one another because:

- both are required to make the primary biological molecules (carbohydrates, fats, proteins, and sugars). - both are liberated into the environment when organisms decompose. - microorganisms have important roles in the cycling of each. -All of these choices are correct.

If 5000 kilograms (kg) of biomass are available at the primary consumer level, how many kg of biomass would be available to the tertiary consumers?

5

Of the processes involved in the long-term carbon cycle, which removes CO2 from the atmosphere?

chemical weathering

The equation CaSiO3 + CO2 → CaCO3 + SiO2 takes into account which of these processes associated with the long-term carbon cycle?

chemical weathering

A researcher is measuring atmospheric CO2 levels on cloudy and sunny days. He notices that on cloudy days, CO2 levels appear slightly higher than on sunny days. This is an example of:

correlation

An increased rate of photosynthesis is the most likely explanation as to why atmospheric CO2 levels appear lowest during glacial periods of Earth's history.

false

Glacial ice core data can provide scientists with information about atmospheric CO2 levels for the last 500 million years of Earth's history.

false

Most phosphorus on the planet is found in living organisms.

false

Photosynthesis and respiration were the main causes of fluctuations in atmospheric CO2 levels over the last 500 million years.

false

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

Which of the answer choices is not considered a photosynthetic organism and, therefore, does not remove atmospheric CO2?

human

Whereas food chains show linear energy transfer between organisms, food webs depict more realistically what occurs in an ecosystem.

true

Your body, your house, and your pets are all considered carbon reservoirs.

true

Of the processes involved in the long-term carbon cycle, which introduces CO2 back into the atmosphere?

volcanism

Photosynthesis and respiration affect atmospheric CO2 levels on a _____ timescale, whereas volcanic eruptions affect atmospheric CO2 levels on a _____ timescale.

yearly; century