Ch 25 Study Set

Which of the following are reservoirs of carbon?

All are correct

Which of the following statements is true regarding the carbon cycle?

All are correct

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

CaCO3.

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

Photosynthetic, woody plants first appeared during this period.

Carbon moves through the ecosystem on both short- and long-term scales. Which of the following statements best describes the movement of carbon through short-term time scales of the food chain?

Primary producers fix atmospheric carbon into compounds that will be oxidized by secondary consumers.

Which of the following statements explains how an oxygen rich atmosphere was possible?

Rates of oxygen consumption were lower than rates of photosynthesis.

A researcher is comparing atmospheric CO2 levels in Earth's northern and southern hemispheres during June and August. Since more terrestrial plants are present in the northern hemisphere, what do you expect she will find?

Since atmospheric CO2 measurements represent global amounts, measurements in the northern and southern hemispheres will be (approximately) the same.

A botanist is comparing the metabolic pathways for photosynthesis in cyanobacteria and in redwood trees. What do you expect she will find?

These two pathways will actually be quite similar, though subtle differences may exist.

Trout and amoebas are both heterotrophs, and can inhabit similar environments (for example, a freshwater pond). However, these organisms are very different when it comes to their shape and size. Why?

Trout and amoebas utilize different sources of C6H12O6 (or other organic compounds).

Which of the following organisms is considered a primary consumer?

a grasshopper

Recall that photosynthetic rates remain relatively constant in regions near the equator. Imagine that tropical environments persisted throughout Earth's northern and southern hemispheres (i.e., Earth's entire climate mirrored 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 (atmospheric CO2 levels would not seasonally oscillate, but would have increased over time)

Which of the following factors likely contributed to the accumulation of O2 within Earth's atmosphere?

all are correct

Carbon is incorporated into the skeletons of corals and other marine organisms through the process of _____. The CaCO3 making up these skeletons, in turn, becomes a major component of sedimentary rocks after these organisms die.

biomineralization

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

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

chemical weathering

Because the products of photosynthesis are used as the reactants of respiration, both processes are considered:

complementary.

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

correlation.

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

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

Cellular respiration is a process unique to animals and is not undertaken by plants.

false

If all of the tertiary consumers were removed from an environment, the associated food web (and thus the carbon cycle) would collapse.

false

If researchers never evaluated the amount of 14C in the atmosphere, they could still use 13C levels to demonstrate causation between human activities and increased atmospheric CO2.

false

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

The diverse array of photosynthetic plants and microbes is the result of different sources of CO2, and has little to do with environmental conditions.

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 does not depict the flow of carbon through an environment as being dependent on a single primary producer, consumer, and decomposer.

food web

Which of the following is not considered a photosynthetic organism, and so would not remove atmospheric CO2?

human

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 following except:

photosynthesis

The term that describes the movement of Earth's crust and includes the process of subduction is _____.

plate tectonics

Decomposers are vital components of a food web because they: C6H12O6.

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

the burning of fossil fuels

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; it is not immediately reintroduced back into the atmosphere.

true

The ocean, much like the atmosphere, can serve as a sink for man-made CO2. In fact, both Earth's atmosphere and the ocean store roughly equal amounts of man-made CO2.

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