Biology 1108 Chapter 46 LC

Researchers are measuring Earth's atmospheric CO2 levels, gathering data on CO2 levels in northern and then southern hemispheres. What do you expect that they will find?

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

Which point on the graph would reflect increased storage of carbon in carbon sinks due to increased plant diversity?

Point D

Which of the statements is true regarding subduction?

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

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

food web.

If all volcanic activity were to stop tomorrow, there would be a _____ reduction in carbon flux into the atmosphere.

99%

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.

Why does the burning of fossil fuels have such a large impact on atmospheric carbon concentrations?

Burning fossil fuels results in the release of carbon held in sinks for over 350 million years, and there is no other reservoir capable of holding that amount of carbon.

In which period shown on the figure would you expect glacial ice to be the lowest?

Cenozoic

Consider the graph shown. Studies using isotopic CO2 ratios have shown that the ratio of 13C /12C in the atmosphere has declined. What would it indicate if the ratio of 13C /12C had remained constant?

Detecting an increase in CO2 emissions from the burning of fossil fuels would be less likely.

Which of the statements is true regarding the carbon cycle?

It cycles both carbon and H2O, It involves both long- and short-term processes, It evolved before plants appeared on Earth, It was based on microbes during the early stages of Earth's history.

Why are CO2 levels higher during interglacial periods?

Lower ice levels cause CO2 trapped in air bubbles to be released, raising temperatures.

Decomposers release nitrogen to the soil in the form of _____ and phosphorous in the form of _____.

NH3; PO43—

Marine trophic pyramids are inverted in terms of biomass but not energy. Which statement best reflects why this is the case?

Organisms at the bottom of the trophic pyramid have high rates of primary production and replenish biomass eaten by primary consumers with high reproductive rates.

Carbon moves through ecosystems on both short- and long-term scales. Which of the 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.

If we were able to restore the forests in the Northern Hemisphere that have been clear-cut in the past 300 years, what changes to the data shown in the graph would you expect?

The year-to-year oscillation in CO2 levels would be more pronounced in that more CO2 could be absorbed each season.

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).

Which change to an ecosystem is most likely to increase the amount of biomass available to primary consumers?

adding more than 80 kg of nitrogen per hectare (N/Ha)

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

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

If N-fixing bacteria were eliminated, the flux of N through the nitrogen cycle would:

decrease because more N2 would remain in the atmosphere.

If chemical weathering of rocks, a process that releases phosphorous into the environment, were to decrease by 50%, what effect would it have on organisms in a food web?

disrupted cell membrane production in consumers

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

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

false

Scientists can gain information about ancient atmospheric CO2 levels through ice core data. CO2 in ice cores is primarily the result of sediments being trapped in glaciers, which scientists can subsequently assess for different carbon isotopes 13C, 12C, and 14C.

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

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

You would expect to see the lowest rates of primary productivity:

in the open ocean.

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

An examination of geologic processes that drive the long-term carbon cycle shows that:

more carbon is moved from the atmosphere into geologic reservoirs than is released from geologic reservoirs into the atmosphere

Organisms in an ecosystem are linked to their physical environment through the cycling of _____ and the transfer of _____.

nutrients; energy

By eating primary producers, primary consumers are able to obtain _____ for making nucleic acids.

phosphorus

The higher the level of biodiversity of a region, the greater its: Please choose the correct answer from the following choices, and then select the submit answer button. Answer choices

primary productivity

Consider the figure shown. Which organism would have the least effect if removed from the food web?

raccoon

The Olympic Mountain Range is an actively growing mountain range, where two tectonic plates are continuing to move each other, exposing more sedimentary rock. This movement of one tectonic plate contributing to the growth of the mountain chain will primarily:

return carbon to the ocean through weathering.

Many organisms make up a food web. If snakes are removed from the food web, then:

tertiary consumer population sizes will decrease.

Much of the terrestrial animal diversity seen today would not be possible without:

the high diversity of plants in terrestrial environments.

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

trophic pyramid.

An increase in phosphate runoff would increase the amount of biomass available to primary consumers in marine trophic pyramids.

true

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

true

If all organisms that fix nitrogen were eradicated from a forested region, then:

usable forms of nitrogen would only be available from urine or ammonification.