Deck 28: How Do Ecosystems Work

Question 1

Only a small percentage of the energy that arrives at the outer atmosphere of Earth reaches the surface and is then captured within ecosystems. What percentage is captured by photosynthetic organisms?

A)5%
B)3%
C)1%
D)0)03%
E)0)0001%

Answer 1

D

Question 2

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

Answer 2

E

Question 3

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

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

Answer 3

B

Question 4

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)25%
B)21%
C)14%
D)5%
E)1%

Question 5

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

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

Question 6

The atoms that make up the molecules in our bodies:

A)cannot be rearranged to make different molecules under any circumstances.
B)have nearly all been on Earth throughout its entire history.
C)traveled to Earth as electromagnetic waves.
D)were all formed recently by nuclear fusion on the sun.
E)will be lost back to space soon after we die.

Question 7

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

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

Question 8

Which level of the energy pyramid has the greatest biomass?

A)heterotrophs
B)producers
C)carnivores
D)primary consumers
E)secondary consumers

Question 9

What happens to 99% of the energy that reaches Earth's atmosphere?

A)It is captured by plants and used in photosynthesis.
B)It is destroyed by the atmosphere.
C)It is used as heat by animals.
D)It is absorbed by rocks on Earth's crust.
E)It is reflected or absorbed by the atmosphere, clouds, and Earth's surface.

Question 10

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

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

Question 11

The majority of the energy on Earth originates from:

A)coal.
B)nuclear sources.
C)volcanoes.
D)the sun.
E)oil.

Question 12

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

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

Question 13

The first trophic level of an ecosystem consists of:

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

Question 14

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

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

Question 15

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

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

Question 16

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

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

Question 17

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

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

Question 18

A carnivore is usually a(n):

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

Question 19

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

Question 20

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

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

Question 21

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

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

Question 22

Chemicals that mimic the effect of reproductive hormones are:

A)macronutrients.
B)biodegradable.
C)micronutrients.
D)detritus.
E)endocrine disruptors.

Question 23

Detritus feeders consume:

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

Question 24

Autotrophs gain energy from:

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

Question 25

If a couple was attempting to get pregnant, which foods should they eat to avoid endocrine disruptors?

A)organic grains, fruits, and vegetables
B)high-fat salmon
C)DDT-treated vegetables
D)high-level carnivores like tuna
E)meals microwaved in plastic bags

Question 26

The three major reservoirs of carbon are:

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

Question 27

Which trophic level has the least bioaccumulation?

A)heterotrophs
B)primary producers
C)secondary consumers
D)primary consumers
E)tertiary consumers

Question 28

Which nutrient cycle lacks an atmospheric reservoir?

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

Question 29

Carnivores are usually:

A)secondary consumers.
B)primary consumers.
C)autotrophs.
D)detritus consumers.
E)consumer producers.

Question 30

Net primary production is:

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

Question 31

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

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

Question 32

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

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

Question 33

_______ is/are a crucial nutrient reservoir of phosphorus that is available to organisms.

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

Question 34

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

Question 35

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)1,000 grams.
B)100 grams.
C)10 grams.
D)1 gram.
E)0)1 gram.

Question 36

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

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

Question 37

The community of heterotrophic protists and invertebrate animals, such as earthworms, pillbugs, mites, and pseudoscorpions, that live in the leaf litter on the shady floor of a deciduous forest obtains its energy and nutrients primarily from:

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

Question 38

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. People who ate which of the following seafoods would you expect were most affected?

A)kelplarge, multicellular, photosynthetic protists
B)krillsmall crustaceans that eat tiny microscopic algae
C)mussels that feed on 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 39

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

A)the atmosphere
B)some rocks and soil
C)producers
D)consumers
E)decomposers

Question 40

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

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

Question 41

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 those same climatic conditions be found?

A)farther north
B)farther south
C)farther west
D)in the same place; global warming will not affect the location of climatic regions
E)nowhere; those conditions will not occur anywhere on the continent

Question 42

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

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

Question 43

Acid precipitation is the result of interference with the ________ cycles.

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

Question 44

The greenhouse effect is:

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

Question 45

A major ecological concern, the greenhouse effect, is caused by:

A)the release of heat energy from burning fossil fuels.
B)the release of carbon dioxide from the burning of wood, coal, and oil.
C)the destruction of ozone in the upper atmosphere.
D)overuse of fertilizers in farming.
E)global warming.

Question 46

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

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

Question 47

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

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

Question 48

The assaults of acids dissolved in precipitation and dry particles of sulfuric acid are together known as:

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

Question 49

In nitrogen-limited ecosystems, legumes often dominate over other plants because they:

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

Question 50

Micronutrients:

A)are needed in smaller quantities than macronutrients but are just as essential.
B)are smaller molecules than macronutrients.
C)benefit organisms if they are present but are not essential.
D)include water, carbon, nitrogen, and phosphorus.
E)are rarely found in the environment.

Question 51

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

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

Question 52

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)Acid rain makes the gulf's water too acidic to support fish.
B)Global warming is making the river water too hot for the fish to tolerate.
C)There are high levels of mercury in the river water.
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 53

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

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

Question 54

What are the sources of sulfur in the atmosphere?

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

Question 55

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

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

Question 56

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 plant respiration.
D)reducing photosynthetic rates.
E)increasing the amount of radiation from Earth's surface.

Question 57

The hydrologic cycle is different from other nutrient cycles in that:

A)water is chemically unchanged throughout the cycle.
B)the ocean is involved.
C)the atmosphere is involved.
D)the soil is not involved.
E)water is not recycled, but flows one way through ecosystems.

Question 58

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

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

Question 59

Nitrogen fixation:

A)is due to a lack of decomposers and causes nitrogen to accumulate in dead organic matter.
B)is the conversion of ammonia to nitrate.
C)is the conversion of nitrate to ammonia.
D)is undertaken by denitrifying bacteria.
E)is the synthesis of ammonia from nitrogen gas by certain bacteria.

Question 60

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

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

Question 61

Many climatologists blame the recent extremes in weather on global warning. True or False?

Question 62

Iron is a limiting factor in many aquatic ecosystems. If the iron level is increased, the amount of phytoplankton decreases. True or False?

Question 63

Horses and cows are primary consumers. True or False?

Question 64

Plants often grow poorly in sterilized soils because the soils lack nitrogen-fixing bacteria. True or False?

Question 65

Detritus feeders remove nutrients from the food chain. True or False?

Question 66

Burning high-sulfur coal increases acid deposition. True or False?

Question 67

Fossil fuels are the major reservoir in the phosphorus cycle. True or False?

Question 68

The aquifers are underground reservoirs in the hydrologic cycle. True or False?

Question 69

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

Question 70

Once used by an organism, carbon and nitrogen ions are unavailable for other organisms. True or False?

Question 71

The major reservoir in the nitrogen cycle is the water. True or False?

Question 72

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

Question 73

Minerals that are needed in only trace amounts are macronutrients. True or False?

Question 74

Deforestation decreases the levels of greenhouse gases in the atmosphere. True or False?

Question 75

The primary source of Earth's energy is the sun. True or False?

Question 76

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

Question 77

The primary consumers in marine food chains are zooplankton. True or False?

Question 78

The level of environmental toxins like DDT decreases as you move into the higher trophic levels. True or False?

Question 79

When a rabbit eats the lettuce in your garden, the rabbit uses all of the energy in the lettuce. True or False?

Question 80

Carbon dioxide is the only greenhouse gas. True or False?