bly 122 chp 46 learning curve

Imagine that a research team has discovered a leaf fossil from the Cambrian Period that is 500 million years old. They notice that the leaf had very few stomata compared to present-day leaves. What does this tell the researchers about atmospheric CO2 levels during the Cambrian Period? *Atmospheric CO2 levels are not correlated with numbers of stomata. *Atmospheric CO2 levels during the Cambrian Period were equal to present-day levels. *Atmospheric CO2 levels were lower during the Cambrian Period than today. *Atmospheric CO2 levels were higher during the Cambrian Period than today.

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

Which of the statements is true regarding subduction? *It adds new crust to Earth's surface via volcanic activity. *It is unrelated to Earth's plate tectonics. *It permanently removes carbon from Earth's surface. *It permanently adds carbon to Earth's atmosphere. *The carbon it removes is eventually returned to the atmosphere by volcanism

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

Following the 10% rule for energy moving through a trophic pyramid, an increase of 10% at the level of primary producer would increase the biomass supported in the secondary producer trophic level by: 0.01% 0.1% 1% 10%

0.1%

If all volcanic activity were to stop tomorrow, there would be a _____ reduction in carbon flux into the atmosphere. *66% *33% *99%

99%

Which of the answer choices is a reservoir of carbon? *the atmosphere *organisms *oceans *soil *All of these choices are correct.

All of these choices are correct.

Why does the burning of fossil fuels have such a large impact on atmospheric carbon concentrations? *The impact is minimal rather than large because volcanic activity has been raising CO2 levels in the atmosphere at a constant rate since Earth formed. *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. *The impact is large because the CO2 rises to a level in the atmosphere that cannot be utilized by or absorbed by plants through photosynthesis. *Burning fossil fuels does not have a large impact because current plant biomass can absorb the CO2 through photosynthesis.

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.

The majority of carbon stored in abiotic reservoirs is in the form of: *CaCO3. *H2CO3. *C6H12O6. *CH4. *CO2.

CaCO3.

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

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? *There would be a change in CO2 levels in ice cores. *Detecting an increase in CO2 emissions from the burning of fossil fuels would be less likely. *It would suggest that volcano activity was responsible for rising CO2 levels *It would suggest that plants have started incorporating more 13C into their tissues.

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

Which of the statements is true regarding chemical weathering? *It relies on the acid SiO2. *It contributes to the accumulation of CaCO3 in oceans. *It releases CO2 into the atmosphere. *It relies on bacteria to break down rocks. *It plays a major role in the short-term carbon cycle.

It contributes to the accumulation of CaCO3 in oceans.

Why are CO2 levels higher during interglacial periods? *Temperatures are higher during interglacial periods, causing higher CO2 levels. *Lower ice levels cause CO2 trapped in air bubbles to be released, raising temperatures. *There is more land covered by plants, so more CO2 is fixed during photosynthesis. *There are more organisms respiring, so the ratio of CO2 to O2 in the atmosphere is equal.

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

Decaying organic matter is an important source of: *N2. *NH3. *NO2—. *NO3—.

NH3.

Marine trophic pyramids are inverted in terms of biomass but not energy. Which statement best reflects why this is the case? *Organisms near the top of the trophic pyramid don't weigh very much and move over larger areas than organisms at the base of the trophic pyramid. *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. *Organisms near the top of the trophic pyramid don't weigh very much and have high reproductive rates. *Organisms at the bottom of the trophic pyramid are large in size, so they are able to support larger organisms that occupy the higher trophic levels.

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.

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? *Oxygen-based mammalian life evolved on the planet 100,000 years ago, and photosynthetic organisms evolved 50,000 years ago. *Photosynthetic organisms evolved on the planet 50,000 years ago. *Photosynthetic organisms evolved on the planet 100,000 years ago but went extinct 50,000 years ago. *Oxygen-based mammalian life evolved on the planet 100,000 years ago.

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

Recall that during the Paleozoic Era, atmospheric CO2 levels decreased. Why? *Earth's plate tectonics changed dramatically, and subduction increased. *Photosynthetic, woody plants first appeared during this period. *Volcanism decreased during this period. *New, extensive mountain ranges formed and chemical weathering decreased.

Photosynthetic, woody plants first appeared during this period.

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? *There would be no change in atmospheric CO2 levels because the amount released to the atmosphere is too great to be absorbed through photosynthesis. *The year-to-year oscillation in CO2 levels would be more pronounced in that more CO2 could be absorbed each season. *The oscillation would increase because respiration levels would increase.

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

Consider the levels of atmospheric CO2 shown in the graph. Why isn't the point for CO2 concentration the same for April 2015 and April 2016? *There is variation in the instruments that collect CO2 data. *There are seasonal fluctuations in CO2 levels during different seasons in the Northern Hemisphere. *There is a continual rise from one year to the next in CO2 levels on the planet. *Respiration levels remain constant over time, but there is variation in the amount of CO2 produced through respiration.

There is a continual rise from one year to the next in CO2 levels on the planet.

As shown in the graph, we see decreases in CO2 that follow an annual pattern. This pattern is attributed to seasonal fluctuations in photosynthesis from large forests in the Northern Hemisphere. There are no large deciduous temperate forests in the Southern Hemisphere. How would you predict the CO2 concentration figure to change if there were deciduous temperate forests in the Southern Hemisphere as well ? *There would still be an increase year over year, but the magnitude of change in CO2 levels would be smaller. *There would still be fluctuations throughout the year, but the concentration levels for any one month on the graph would be the same from one year to the next. *There would no longer be fluctuations, and the curve would be closer to a flat line. *There would still be an increase year over year, but the magnitude of change in CO2 levels would be greater.

There would still be an increase year over year, but the magnitude of change in CO2 levels would be greater.

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 positrons in 12C, 13C, and 14C *by the number of electrons in 12C, 13C, and 14C *by the number of protons in 12C, 13C, and 14C *by the biomasses of 12C, 13C, and 14C *by the number of neutrons in 12C, 13C, and 14C

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

The equation CaSiO3 + CO2 → CaCO3 + SiO2 takes into account which of these processes associated with the long-term carbon cycle? *subduction *plate tectonics *chemical weathering bacteria-based oxidation *volcanism *bacteria-based oxidation

chemical weathering

Which group in a food web is responsible for returning inorganic compounds back to the environment? *tertiary consumers *decomposers *primary producers *primary consumers *secondary consumers

decomposers

Examining the relationship between primary producers, primary consumers, and secondary consumers is one way to track the flow of _____ through a system. *energy in the form of heat *energy contained in proteins *energy contained in organic compounds *energy contained in fossil fuels

energy contained in organic compounds

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. *true *false

false

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

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. *true *false

false

Nutrient cycling through ecosystems can be depicted using a(n): *ecosystem. *trophic pyramid. *food web. *food chain. *Calvin cycle.

food web.

You would expect to see the lowest rates of primary productivity: *in the rainforest. *in and around a river. *in the open ocean. *in and around a lake. *on a mountain.

in the open ocean.

Measuring the isotopic composition of atmospheric CO2 shows that the burning of fossil fuels has led to _____ CO2 levels over the last 200 years. *increasing *decreasing

increasing

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 *soil < the atmosphere < sedimentary rocks < living organisms *the atmosphere < soil < living organisms < sedimentary rocks *sedimentary rocks < soil < living organisms < the atmosphere *soil < living organisms < sedimentary rocks < the atmosphere

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. *less carbon is moved from the atmosphere into geologic reservoirs than is released from geologic reservoirs into the atmosphere. *the same amount of carbon is moved from the atmosphere into geologic reservoirs as the amount released from geologic reservoirs into the atmosphere.

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; sunlight *energy; nutrients *sunlight; nutrients *nutrients; energy *nutrients; water

nutrients; energy

Which biogeochemical cycle does not include oxidation and reduction reactions that provide energy to microorganisms? *None of the other answer options is correct. *phosphorus *nitrogen *carbon

phosphorus

In a pond, tadpoles eat algae and fish eat the tadpoles. Around the pond, grasshoppers eat grass and, at night, are preyed upon by bats. Other bats eat the fish that eat the tadpoles. In this community, the tadpoles are: *primary producers. *tertiary consumers. *secondary consumers. *primary consumers. *decomposers.

primary consumers

Consider the figure shown. Which organism would have the least effect if removed from the food web? *raccoon *fox *duck *grasshopper

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. *return carbon to sedimentary rocks through sedimentation of shells and skeletons. *return carbon to the atmosphere through volcanic activity. *return carbon to the atmosphere through oxidation of ancient organic matter.

return carbon to the ocean through weathering.

Phosphorous that is incorporated into primary producers returns to geologic reservoirs through the process of: *chemical weathering. *decomposition. *volcanic eruptions. *sedimentation.

sedimentation

Many organisms make up a food web. If snakes are removed from the food web, then: *primary productivity will increase. *tertiary consumer population sizes will decrease. *tertiary consumers will eat fewer birds. *small mammal populations will decrease.

tertiary consumer population sizes will decrease.

Energy flow through ecosystems can be depicted using a(n): *trophic pyramid. *food chain. *food web. *ecosystem. *Calvin cycle.

trophic pyramid.

The evolution of biodiversity on the planet can be linked to patterns in the carbon cycle over time. *true *false

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 *false

true

Of the processes involved in the long-term carbon cycle, which introduces CO2 back into the atmosphere? *volcanism *carbonate precipitation *respiration *chemical weathering *photosynthesis

volcanism

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

yearly; century