BIO 1108 CH 46 LC

Which of the answer choices is a reservoir of carbon?

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

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

NO3-

Imagine that scientists have discovered a new planet that is apparently devoid of life but has ice caps located at the poles. These ice caps reveal that the planet's atmospheric O2 levels sharply increased about 1,000,000 years ago but then quickly dropped 50,000 years ago. What could account for these changes in atmospheric O2 levels?

Photosynthetic organisms evolved on the planet 100,000 years ago but went extinct 50,000 years ago.

Which of the statements explains how an oxygen-rich atmosphere became possible on Earth?

Rates of oxygen consumption are lower than rates of photosynthesis.

Which of the statements is true regarding subduction?

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

A botanist is comparing the metabolic pathways for photosynthesis in cyanobacteria and redwood trees. What do you expect that 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, such as a freshwater pond. However, these organisms are very different when it comes to their shape and size. Why?

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

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

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.

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

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

false

Most phosphorus on the planet is found in living organisms.

false

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

The rate of respiration _____ throughout the year.

remains more or less constant

The broad base at the primary producer level in a trophic pyramid is due to all of the answer choices except:

the larger body size of primary producers compared with organisms at other levels.

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

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

volcanism