Deck 29: Energy Flow and Nutrient Cycling in Ecosystems

Question 1

The amount of energy captured by plants and made available to consumers in an ecosystem is called

A) energy pyramid.
B) biological magnification.
C) nutrient cycling.
D) net primary productivity.
E) secondary trophic level.

Answer 1

D

Question 2

If the plants in a community produce 500 grams of organic matter per square meter per year that is available for animals in the community to eat, this amount of energy is known as the

A) availability factor of the community.
B) trophic factor of the community.
C) net primary productivity of the community.
D) secondary productivity of the community.
E) consumership of the community.

Answer 2

C

Question 3

What are the most basic components of all ecosystems?

A) Producers, consumers, and decomposers
B) Volcanoes, wind, oceans, and other abiotic parts
C) Nutrients and energy
D) Communities of organisms
E) The living, or biotic part, and the abiotic

Answer 3

E

Question 4

The amount of energy lost as it passes from one trophic level to another is approximately

A) 90%.
B) 99%.
C) 50%.
D) 63%.
E) 75%.

Question 5

The atoms that make up the molecules in our bodies

A) came from a wooly mammoth.
B) will be lost back to space soon after we die.
C) were once part of a dinosaur.
D) have nearly all been on Earth throughout its entire history.
E) were all formed recently by nuclear fusion on the sun.

Question 6

What proportion of the solar radiation that reaches Earth's surface is visible light?

A) It is captured by plants and used in photosynthesis.
B) About half is visible light.
C) About 90% of it is visible light.
D) Most of the radiation is absorbed by rocks on Earth's crust.
E) A small fraction is visible light.

Question 7

The first trophic level of an ecosystem consists of

A) heterotrophs.
B) secondary consumers.
C) producers.
D) detritus feeders.
E) primary consumers.

Question 8

The are an important and often overlooked group of organisms that release nutrients into the soil or water.

A) heterotrophs
B) decomposers
C) autotrophs
D) tertiary consumers
E) producers

Question 9

The amount of life that an ecosystem can support is determined primarily by the

A) number of producers and their efficiency.
B) number of heterotrophs.
C) efficiency of the consumers.
D) efficiency of the heterotrophs.
E) number of chemoautotrophs.

Question 10

Certain bacteria and fungi that are important in nutrient recycling because they release nutrients from dead organisms back into the ecosystem are

A) recyclers.
B) detritus feeders.
C) carnivores.
D) decomposers.
E) autotrophs.

Question 11

If a fox eats a rodent that ate a smaller insect that ate a plant, the fox is a(n)

A) tertiary consumer.
B) autotroph.
C) secondary consumer.
D) producer.
E) primary consumer.

Question 12

A deer that gets its energy from eating plants is a(n)

A) omnivore.
B) producer.
C) carnivore.
D) tertiary consumer.
E) herbivore.

Question 13

A carnivore is usually a(n)

A) autotroph.
B) primary producer.
C) secondary consumer.
D) primary consumer.
E) secondary producer.

Question 14

If a field contains approximately 1,000 kilocalories of energy in grass, which is eaten by crickets, which are eaten by birds, then approximately how many kilocalories of energy could be in the birds that live in this field?

A) 90
B) 1,000
C) 100
D) 10
E) 900

Question 15

How much of the energy that reaches Earth's outer atmosphere from the sun is available for photosynthesis in plants at Earth's surface?

A) 95%
B) 44%
C) 71%
D) 55%
E) 1%

Question 16

If a bird eats an insect that ate a plant, the bird is considered a(n)

A) primary consumer.
B) secondary consumer.
C) autotroph.
D) producer.
E) tertiary consumer.

Question 17

The photosynthetic bacteria that form the basis of the food chain in the Great Salt Lake are classified as

A) secondary consumers.
B) carnivores.
C) omnivores.
D) herbivores.
E) producers.

Question 18

A carnivorous plant, such as a sundew, may be considered both a when it eats a carnivorous spider.

A) primary consumer and a secondary consumer
B) primary consumer and a tertiary consumer
C) producer and a tertiary consumer
D) producer and a secondary consumer
E) producer and a primary consumer

Question 19

Which level of the energy pyramid has the greatest biomass?

A) Heterotrophs
B) Primary consumers
C) Secondary consumers
D) Producers
E) Carnivores

Question 20

Organisms that must rely on complex, high- energy molecules produced by other organisms for survival are

A) autotrophs.
B) heterotrophs.
C) denitrifying bacteria.
D) producers.
E) cyanobacteria.

Question 21

In 1956, people in Minamata, Japan, began to exhibit severe neurological disorders and birth defects. This problem was eventually attributed to methylmercury, a water- insoluble and breakdown- resistant chemical formed from mercury dumped into the adjacent bay by a local factory. Which of the following types of seafood would have the highest levels of methylmercury, and therefore cause the severest effects?

A) Kelp (large, multicellular, photosynthetic protists)
B) Mussels that feed on tiny microscopic algae
C) Krill (small crustaceans that eat tiny microscopic algae)
D) Sea urchins that feed on kelp
E) Tuna that feed on smaller fish that feed on krill that feed on algae

Question 22

Which nutrient cycle lacks an atmospheric reservoir?

A) Oxygen
B) Nitrogen
C) Water
D) Carbon
E) Phosphorus

Question 23

is (are) a crucial nutrient reservoir of phosphorus that is available to organisms.

A) The atmosphere
B) Consumers
C) Rocks
D) Autotrophs
E) Oceans

Question 24

What is biological magnification?

A) The process of making small living organisms larger
B) The abnormal growth of organisms
C) The accumulation of toxic substances in a living organism
D) An increase in the size of a population
E) The breakdown of macromolecules into harmless substances

Question 25

Which trophic level has the LEAST biological magnification?

A) Tertiary consumers
B) Secondary consumers
C) Heterotrophs
D) Primary consumers
E) Primary producers

Question 26

Autotrophs gain energy from

A) secondary consumers.
B) the sun and inorganic nutrients.
C) omnivores.
D) secondary producers.
E) primary producers.

Question 27

Bacteria that live in deep- sea thermal vents use energy from inorganic hydrogen sulfide (H₂S) to make organic molecules from carbon dioxide and are thus

A) tertiary consumers.
B) primary consumers.
C) decomposers.
D) secondary consumers.
E) producers.

Question 28

Phosphorus, which is often a limiting nutrient in ecosystems, is important because it

A) is part of the hydrologic cycle.
B) is found only in sedimentary rocks.
C) evaporates quickly.
D) is necessary for the production of cellulose so that autotrophs can grow and provide food for heterotrophs.
E) is needed for molecules such as adenosine triphosphate (ATP), cell membranes, and nucleic acids.

Question 29

Which of the following terms correctly describes carnivores?

A) Autotrophs
B) Detritus consumers
C) Secondary consumers
D) Primary consumers
E) Consumer producers

Question 30

If a couple was attempting to get pregnant, which foods should they eat to avoid ingesting high amounts of toxins?

A) High- level carnivores such as tuna
B) High- fat salmon
C) DDT- treated vegetables
D) Meals microwaved in plastic bags
E) Organic grains, fruits, and vegetables

Question 31

In open- water marine ecosystems, the occupy the same trophic level as the giant sequoias (redwoods) in the forests of California.

A) tiny, multicellular zooplankton ("animal drifters") that feed on phytoplankton
B) fast- swimming, fish- eating tuna
C) giant, squid- eating whales
D) microscopic, single- celled algae (protists) called phytoplankton ("plant- like drifters")
E) microscopic bacteria that decompose all the other organisms once they have died

Question 32

Detritus feeders consume

A) dead organic matter.
B) fungi and bacteria.
C) herbivores.
D) secondary consumers and primary debris.
E) plants and plant debris.

Question 33

In a grassland of Kansas, 1,000 grams of grass are produced per square meter per year by all the different grass species. A theoretical upper limit to the biomass of secondary consumers that can be supported in this ecosystem is

A) 10 grams.
B) 100 grams.
C) 1,000 grams.
D) 0.1 gram.
E) 1 gram.

Question 34

Which of the following components is NOT involved in the phosphorus cycle?

A) Consumers
B) The atmosphere
C) Decomposers
D) Producers
E) Some rocks and soil

Question 35

The three major reservoirs of carbon are

A) oceans, the atmosphere, and fossil fuels.
B) rocks, the atmosphere, and guano.
C) acid precipitation, carbon- fixing bacteria, and oceans.
D) soil, water, and the atmosphere.
E) fossil fuels, legumes, and micronutrients.

Question 36

Net primary production is

A) heterotrophic production minus autotrophic production per unit of land per unit of time.
B) energy made by autotrophs minus energy consumed by heterotrophs, and measured as biomass.
C) energy that photosynthetic organisms make available to other organisms over a given period of time.
D) energy stored by secondary consumers from primary biomass.
E) heterotrophic production per unit of land per unit of time.

Question 37

If you are attempting to minimize the amount of mercury in your diet, you should eat

A) high- level carnivores such as tuna.
B) low- level carnivores such as tilapia.
C) herbivores such as cattle.
D) omnivores such as hogs.
E) producers such as fruits and vegetables.

Question 38

The community of detritivores, such as earthworms, millipedes, slugs, and pseudoscorpions, living in the leaf litter on the shady floor of a deciduous forest obtains its energy and nutrients primarily from

A) photosynthesis or algae living in the soil beneath the leaves.
B) predation on one another.
C) chemosynthesis by green and purple sulfur bacteria living on the surface of the leaves.
D) decomposition of the leaves of deciduous trees that fall on the surface of the soil.
E) carbohydrates formed in the roots of the trees that leach out into the surrounding soil.

Question 39

Oceans, the atmosphere, and fossil fuels are large reservoirs of

A) phosphorus.
B) water.
C) carbon.
D) nitrogen.
E) oxygen.

Question 40

A snake that eats a small rabbit that feeds on grass is classified as a(n)

A) primary producer.
B) primary consumer.
C) secondary consumer.
D) autotroph.
E) tertiary consumer.

Question 41

Why is the concentration of carbon dioxide in Earth's atmosphere rapidly increasing?

A) Earth is warming.
B) The ozone layer has become much thinner.
C) More photosynthesis is occurring.
D) The oceans are cooling.
E) Many human activities release carbon dioxide.

Question 42

Forests along rivers in the Pacific Northwest that have lost their salmon populations are less productive because the

A) nitrogen the fish brought from the ocean and contained in their tissues has been lost.
B) dams that prevented the fish from migrating also flooded the forests.
C) fishers who overharvested the salmon compacted the soil in the process.
D) global warming that wiped out the fish has also harmed the trees.
E) pollution that killed the fish has also directly affected the trees.

Question 43

Micronutrients

A) include water, carbon, nitrogen, and phosphorus.
B) benefit organisms if they are present but are not essential.
C) are needed in smaller quantities than are macronutrients.
D) are not naturally occurring and must be synthesized by scientists.
E) are smaller molecules than are macronutrients.

Question 44

In an area with nitrogen- poor soil, legumes often dominate over other plants because they

A) have long taproots that can extract nitrogen from deeper down in the soil.
B) have unique access to the large atmospheric pool of nitrogen thanks to their symbiotic bacteria.
C) inhibit the growth of denitrifying bacteria around their roots, thus keeping more nitrate in the soil.
D) do not need nitrogen at all.
E) obtain supplemental nitrogen by trapping insects and other prey.

Question 45

The greenhouse effect, which has become a major ecological concern, is caused by

A) the increase in atmospheric concentrations of greenhouse gases (CO₂,CH₄, and N2O).
B) overuse of fertilizers in farming.
C) the release of heat energy from burning fossil fuels.
D) the destruction of ozone in the upper atmosphere.
E) global warming.

Question 46

What are the sources of sulfur in the atmosphere?

A) Mostly transportation modes, such as autos, trucks, and planes
B) Decomposition and small amounts from pollution
C) Natural and human sources, in equal amounts
D) Mostly (over 90%) volcanoes and photosynthetic bacteria
E) Volcanoes and hot springs, but mostly (about 75%) human activities such as burning coal

Question 47

When nitrogen oxides and sulfur dioxide combine with water vapor in the air, they are converted to nitric acid and sulfuric acid, respectively. This precipitation that then falls to the Earth is known as

A) nitrogen precipitation.
B) acid fog.
C) decomposition acid.
D) acid deposition.
E) acid precipitation.

Question 48

When you observe a lake that has been affected by acid deposition, you might expect to find

A) excess carbon that will contribute to global warming.
B) low levels of toxic metals and nutrients essential for the growth of biotic organisms.
C) a clear lake with high levels of aluminum, mercury, and lead, but few fish.
D) high levels of dissolved sulfur dioxide.
E) a murky lake with excess algal growth from the deposition of anthropogenic nitrogen.

Question 49

Farmers often include legumes as part of their normal crop rotation. This practice increases the overall production of their crops by

A) suppressing the growth of weeds.
B) helping the soil retain water.
C) making the soil less acidic.
D) adding nitrogen to the soil.
E) adding phosphorus to the soil.

Question 50

The greenhouse effect is the ability of

A) certain gases to retain heat in the atmosphere instead of allowing it to be reflected back into space.
B) structures created by humans to retain solar energy as short- wave radiation.
C) sulfur dioxide and nitrogen oxides to retain heat in the lower atmosphere.
D) sulfur dioxide and nitrogen oxides to retain heat in the upper atmosphere.
E) certain gases to absorb solar heat and reflect the heat to Earth as short- wave radiation.

Question 51

Carbon dioxide and other greenhouse gases cause Earth's temperature to increase by

A) allowing greater transmission of incoming solar radiation.
B) absorbing heat energy and holding it close to Earth.
C) increasing the amount of radiation from Earth's surface.
D) increasing plant respiration.
E) reducing photosynthetic rates.

Question 52

Phosphate fertilizers have increased the amount of phosphate in lakes and other bodies of water. What effect does this increase have on the phytoplankton in the water?

A) It increases their likelihood of being eaten.
B) It stimulates their growth.
C) It causes them to form toxic compounds.
D) It reduces their photosynthetic capacity.
E) It kills them.

Question 53

Once used by an organism, carbon- and nitrogen- based nutrients are unavailable for other organisms.

Question 54

Each summer, a large "dead zone" devoid of fish and other animals develops where the Mississippi River flows into the Gulf of Mexico. What causes this?

A) There are high levels of mercury in the river water.
B) Global warming is making the river water too hot for the fish to tolerate.
C) Acid rain makes the gulf's water too acidic to support fish.
D) High levels of pesticides are used in the Mississippi River basin.
E) Large quantities of fertilizer run off from Midwestern farm fields into the Mississippi River.

Question 55

Burning coal and oil to release energy also releases , which are overloading Earth's nutrient cycles.

A) oxygen, methane, and sulfur
B) sulfur, carbon, and nitrogen
C) sulfur, oxygen, and acid
D) phosphorus, carbon, and nitrogen
E) nitrogen, phosphorus, and potassium

Question 56

Human- caused disturbances of the cycle may be contributing to global warming.

A) sulfur
B) phosphorus
C) carbon
D) hydrologic
E) oxygen

Question 57

The present range of the sugar maple in North America extends from the Atlantic Ocean west to the Mississippi River and from southern Ontario, Quebec, and New Brunswick south to Tennessee and Virginia. If the global temperature rises 10°C in the future, where will the range of sugar maples be found?

A) Farther west
B) Farther south
C) Farther north
D) In the same place; global warming will not affect the heat tolerance of plants.
E) Nowhere; sugar maples will become extinct.

Question 58

Nitrogen is the most abundant element in the atmosphere, and a crucial component of proteins, vitamins, and nucleic acids. However, plants and other producers cannot use nitrogen in its natural form (N2). Nitrogen has to undergo a process called nitrogen fixation. What does this process involve?

A) Ammonia is converted to nitrate.
B) It is the synthesis of ammonia from nitrogen gas by certain bacteria.
C) Nitrate is converted to ammonia.
D) Nitrogen is accumulated in dead organic matter.
E) It is undertaken by denitrifying bacteria.

Question 59

The hydrologic cycle is different from other nutrient cycles in that

A) the ocean is involved.
B) water is not recycled, but flows one way through ecosystems.
C) the biotic part of the cycle plays only a small role.
D) the atmosphere is involved.
E) the soil is not involved.

Question 60

Acid deposition is the result of interference with the cycles.

A) hydrologic and nitrogen
B) sulfur and hydrologic
C) sulfur and nitrogen
D) sulfur and phosphorus
E) hydrologic and phosphorus

Question 61

Plants often grow poorly in sterilized soils because the soils lack nitrogen- fixing bacteria.

Question 62

The major reservoir in the nitrogen cycle is the water.

Question 63

Many climatologists blame the recent extremes in weather on global warning.

Question 64

Carbon dioxide is the only greenhouse gas.

Question 65

Aquifers are underground reservoirs in the hydrologic cycle.

Question 66

The level of environmental toxins such as DDT decreases as you move into the higher trophic levels.

Question 67

Deforestation decreases the levels of greenhouse gases in the atmosphere.

Question 68

Detritus feeders remove nutrients from the food chain.

Question 69

Iron is a limiting factor in many aquatic ecosystems. If the iron level is increased, the amount of phytoplankton (which feed on iron) decreases.

Question 70

The primary consumers in marine food chains are phytoplankton.

Question 71

Macronutrients are elements or small molecules that are needed in only trace amounts.

Question 72

Horses and cows are primary consumers.

Question 73

One of the basic principles of ecosystems is that moves through the ecosystems in a continuous one- way flow.

Question 74

Autotrophs use solar energy to build their own complex organic molecules from inorganic compounds such as water and carbon dioxide.

Question 75

Plants absorb small amounts of carbon from the soil in the form of simple sugars or monosaccharides.

Question 76

Burning high- sulfur coal increases acid deposition.

Question 77

When a rabbit eats the lettuce in your garden, the rabbit uses all of the energy in the lettuce.

Question 78

The primary source of Earth's energy is the sun.

Question 79

Organisms that produce their own food from inorganic compounds through reactions powered by sunlight are heterotrophs.

Question 80

Fossil fuels are the major reservoir in the phosphorus cycle.