ECOL 182R EXAM 2 CH. 53

evolutionary adaptation

change in allele frequencies can increase fitness in new conditions

_____ are secondary consumers. A. Producers B. Herbivores C. Plants D. Cows E. Carnivores

E. Carnivores *Secondary consumers are animals that eat other animals; thus, they are carnivores.

Where do plants get the carbon they use to make organic molecules? A. glucose B. oxygen C. water D. starch E. carbon dioxide

E. carbon dioxide *Plants use the carbon in atmospheric carbon dioxide to make organic molecules.

Plants use _____ as a source of energy. A. minerals B. fats C. oxygen D. vitamins E. light

E. light *Plants use light as a source of energy.

Which of the following is a source of human-fixed nitrogen? I) industrially produced fertilizers II) cultivation of soybeans III) irrigation agriculture A. only I B. only II C. only III D. only II and III E. only I and II

E. only I and II

Major human impacts on ecosystems include farming, logging, and burning. These processes all result in accelerated nutrient export by what common mechanism? A. Vegetation removal B. Soil compaction C. Loss of animal habitat D. Environmental pollution

A. Vegetation removal

Which of the following statements is an example of a negative feedback loop? A. Warmer conditions lead to increased photosynthetic rates and hence an increase in uptake of CO2, which could decrease the temperature. B. Warmer and drier climatic conditions lead to more fires, which in turn release more CO2, which could lead to more warming. C. Warmer conditions in the tundra increase decomposition rates, so more carbon is released from stored soil organic matter into the atmosphere, which leads to more warming. D. A fire generates more heat, which increases combustion, which would cause more fire.

A. Warmer conditions lead to increased photosynthetic rates and hence an increase in uptake of CO2, which could decrease the temperature.

What element is found in all organic compounds? A. carbon B. oxygen C. helium D. iron E. nitrogen

A. carbon *All organic compounds contain carbon.

Which of the following is normally the longest-lived reservoir for carbon? A. fossil fuels B. atmospheric CO2 C. marine plankton (primary producers and consumers) D. wood

A. fossil fuels

The energy invested in the production of new tissue by autotrophic organisms is __________. A. net primary productivity B. gross primary productivity C. gross photosynthetic efficiency D. maintenance

A. net primary productivity

When a human eats a steak, the human is acting as a _____. A. secondary consumer B. producer C. primary consumer D. detritivore E. tertiary consumer

A. secondary consumer *By feeding on a primary consumer, the human is acting as a secondary consumer.

The main cause of the increase in the amount of carbon dioxide in Earth's atmosphere over the past 150 years is __________. A. the burning of larger amounts of wood and fossil fuels B. additional respiration by the rapidly growing human population C. increased worldwide primary production D. increased worldwide standing crops

A. the burning of larger amounts of wood and fossil fuels

Which biome is most productive in terms of NPP per unit area? A.Coral reefs and algal beds B.Tropical rain forests C.Open ocean D.Bare rock and soil

A.Coral reefs and algal beds

A human who just ate a hamburger is eaten by a shark while swimming. The shark is acting as a _____. A. primary consumer B. secondary consumer C. detritivore D. producer E. tertiary consumer

E. tertiary consumer *The shark that ate the human that ate the cow that ate the grass is the tertiary consumer.

Humans are adding nitrogen to ecosystem through

- nitrogen fertilizers - nitrogen-fixing crops - burning of fossil fuels - bacteria - lighting

Which of the following environmental challenges has so far not shown a slowdown, partial recovery, or significant recovery? A. Global warming B. Phosphate pollution C. Acid rain D. Ozone hole

A. Global warming

Which statement about productivity is true? A. Energy can be converted to tissue. B. All net primary productivity is available as food to herbivores. C. Gross primary productivity is that part of productivity unavailable as food to herbivores. D. Several species can be present in each trophic level. E. Production of biomass is highest at the highest trophic levels.

A. Energy can be converted to tissue.

Trophic feeding level

A feeding level in an ecosystem.

food chain

A relatively simple pathway of energy flow through a few species, each at a different trophic level, in an ecosystem. Might include, for example, a primary producer, a primary consumer, a secondary consumer, and a decomposer. A subset of a food web.

Extinction

A species dies out forever.

If the sun were to suddenly stop providing energy to Earth, most ecosystems would vanish. Which of the following ecosystems would likely survive the longest after this hypothetical disaster? A. Benthic ocean B. Tropical rain forest C. Tundra D. Grassland E. Desert

A. Benthic ocean

Why are changes in the global carbon cycle important? A. Carbon dioxide is a greenhouse gas. B. More atmospheric carbon dioxide means that there is less carbon available for the growth of terrestrial plants. C. Less atmospheric carbon means that there are fewer fossil fuels available. D. The global carbon cycle is the only factor affecting Earth's climate.

A. Carbon dioxide is a greenhouse gas.

Which of the following have been presented as a cause for sudden irreversible shifts, such as those seen in a forested area converting to a grassland? A. Climate change, forest fires, and invasive grasses B. Climate change C. Forest fires D. Invasive species E. Climate change and forest fires

A. Climate change, forest fires, and invasive grasses

Which organisms would be found in the same trophic level? A. Crickets and cows B. A plant and an herbivore C. A pack of wolves and a herd of deer D. Pine trees and garden snakes

A. Crickets and cows

Which of the following is a part of the natural nitrogen cycle? A. Decomposers convert detritus into ammonia. B. Animals take up nitrogen in the water they drink. C. Plants take up atmospheric nitrogen through their stomata and convert it to organic forms. D. When plants decompose, fungi absorb the nitrogen and remove it from the natural cycle.

A. Decomposers convert detritus into ammonia.

Of the many links in a nutrient cycle, which one most often limits the overall rate at which nutrients move through an ecosystem? A. Decomposition of detritus B. Plant nutrient uptake and conversion to tissue C. Animal consumption and conversion to tissue D. Plant and animal death and their addition to the dead biomass

A. Decomposition of detritus

Which of the following is an example of ecosystem studies? A. How the energy in sunlight dissipates as it flows through an ecosystem B. Changes in the abundance of a species over time C. How species interact within the ecosystem D. Study of behavioral interactions of predators and prey

A. How the energy in sunlight dissipates as it flows through an ecosystem

Humans have substantially altered the global nitrogen cycle over the past century. How? A. Humans are responsible for almost doubling the amount of nitrogen available by natural means. B. Global warming has reduced the conversion of nitrogen gas to ammonium and other ionic forms. C. The number of gigatons of nitrogen produced has declined in recent years. D. Humans have dramatically increased nitrogen availability as a side effect of internal engine fuel combustion.

A. Humans are responsible for almost doubling the amount of nitrogen available by natural means.

Which of the following statements about biogeochemical cycles is true? A. If a plant dies, the nutrients and the plant biomass become plant litter. B. Nutrients are taken up directly from soil by animals and incorporated into their tissues. C. Nutrients remain in an animal until the animal's death. D. Nutrients cannot move from one trophic level to a higher trophic level the way energy can.

A. If a plant dies, the nutrients and the plant biomass become plant litter.

Devegetation has what effect on ecosystem dynamics? A. It increases nutrient export. B. It increases rates of groundwater recharge (penetration of precipitation to the water table). C. It increases belowground biomass. D. It increases the pool of soil organic matter.

A. It increases nutrient export.

Which of the following statements is true of net primary productivity? A. Marine productivity is highest along coasts and in areas where water wells up from the ocean floor to the surface. B. Deserts and arctic regions have the highest productivity. C. Temperate areas are more productive than tropical areas. D. There is no productivity in the depths of the oceans.

A. Marine productivity is highest along coasts and in areas where water wells up from the ocean floor to the surface.

In ecosystems, why is the term cycling used to describe material transfer, whereas the term flow is used for energy exchange? A. Materials are repeatedly used, but energy flows through and out of ecosystems. B. Both material and energy are recycled, and are then transferred to other ecosystems, as in a flow. C. Materials are cycled into ecosystems from other ecosystems, but energy constantly flows within each ecosystem. D. Both material and energy flow in a never-ending stream within an ecosystem.

A. Materials are repeatedly used, but energy flows through and out of ecosystems.

How does NPP differ from GPP? A. NPP is the amount of energy available for primary consumers, whereas GPP is the amount of energy produced by plants and other producers. B. NPP is the amount of productivity available for decomposers. C. NPP is the amount of energy available at each trophic level, whereas GPP is the sum of the productivity of all the NPPs. D. NPP is dependent on climate, whereas GPP is an intrinsic attribute of the species producing energy

A. NPP is the amount of energy available for primary consumers, whereas GPP is the amount of energy produced by plants and other producers.

What is net primary productivity (NPP)? A. Primary producer biomass or organic material that can be consumed B. Minerals and nitrogen that can be fixed C. Solar energy consumed by non-photosynthetic organisms D. Water maintained in the soil

A. Primary producer biomass or organic material that can be consumed *Correct. NPP measures the amount of primary producer material that is available for consumption after the primary producers have used some portion of GPP for cellular respiration or lost it as heat.

Which of the following is true about the components of ecosystems? A. Primary producers are autotrophs or "self-feeders." B. Secondary consumers are in the second trophic level. C. Primary consumers are organisms that feed on dead organisms or their waste products. D. All autotrophs use the sun's energy to produce chemical energy.

A. Primary producers are autotrophs or "self-feeders."

Which of the following statements about food webs is true? A. Several species can be present in each trophic level. B. Food webs show which species are keystone species. C. A food web depicts a single species as it changes demographically. D. The overall average number of trophic levels found in a food web is about seven.

A. Several species can be present in each trophic level.

Which of the following statements about soil organic matter is true? A. Soil organic matter is rich in humic acids. B. Soil is composed entirely of abiotic components. C. Eventually, the nutrients in soil are converted from inorganic to organic matter, which is then available for uptake by plants. D. If nutrients are converted to an inorganic form, they are no longer available for uptake by plants.

A. Soil organic matter is rich in humic acids.

Over the past decade, which of the following has occurred? A. Terrestrial NPP has decreased in some parts of the world but increased in others. B. NPP has increased in terrestrial environments. C. Terrestrial NPP in the Sahara has increased. D. As predicted by global warming, terrestrial NPP has increased with the warmer temperatures.

A. Terrestrial NPP has decreased in some parts of the world but increased in others.

Which of the following statements is true of biomagnification? A. The concentration of toxin can more than double at each level of the food chain. B. Biomagnification is not an environmental problem. C. Biomagnification is more likely to occur for compounds that are easily excreted by consumers. D. Biomagnification is only a problem in terrestrial environments because the ocean dilutes toxins to a negligible level.

A. The concentration of toxin can more than double at each level of the food chain.

The global carbon cycle involves the movement of carbon among ecosystems. Which of the following is the largest reservoir of carbon? A. The ocean B. Human-induced changes C. Terrestrial ecosystems D. The atmosphere

A. The ocean

Which is true of human impacts on the global water cycle? A. The water table is dropping on every continent. B. Asphalt and pavement increase the amount of groundwater by inhibiting evaporation. C. Use of water from rivers for irrigation effectively replenishes groundwater supplies by percolation. D. Croplands aid in water conservation due to their more extensive root systems compared to plants in natural habitats.

A. The water table is dropping on every continent.

Approximately _____% of the energy at one trophic level is passed on to the next highest trophic level. A. 0-5 B. 5-10 C. 10-15 D. 15-20 E. 90-100

B. 5-10 *Approximately 5-10% of the energy at one trophic level is passed on to the next highest trophic level.

Why does it take 10 times more energy to grow a kilogram of beef than a kilogram of wheat? A. Cattle eat only 10 percent of their body weight. B. Cattle only integrate 10 percent of their food into biomass. C. Only 10 percent of wheat is digestible. D. Wheat weighs less.

B. Cattle only integrate 10 percent of their food into biomass. *Much of the energy is spent on body maintenance and is unavailable to the higher-order consumer.

Why might one get mercury poisoning from eating tuna every day, but not from eating sardines from the same water? A. Sardines are able to excrete the mercury. B. Tuna biomagnify the mercury. C. Sardines do not uptake mercury. D. Mercury is more readily available for uptake in tuna.

B. Tuna biomagnify the mercury. *Tuna eat many sardines and concentrate the mercury in their tissues.

Where do plants get the energy to make organic molecules? A. minerals B. glucose C. vitamins D. light E. water

D. light *In photosynthesis, plants use the energy of light to make organic molecules.

Explain why decomposition rates in a field in Nebraska would differ from the decomposition rates in a field in the Amazon. A. The closer to the Arctic the place is, the more Earth's magnetic field affects the rate to speed it. B. Warmer, wetter climates speed decomposition; cool temperatures slow it. C. Lower gravitation in Amazon speeds decomposition; higher gravitation slows it. D. Decomposition rates depend negatively on the proximity to big amounts of water.

B. Warmer, wetter climates speed decomposition; cool temperatures slow it.

Plants obtain carbon from _____. A. water B. carbon dioxide C. sugar D. oxygen E. glucose

B. carbon dioxide *Plants obtain carbon from carbon dioxide.

Which of these provides your body with energy? A. minerals B. fats C. oxygen D. vitamins E. light

B. fats *Organic molecules, such as fats, are a source of energy.

Which of these is NOT an organic molecule? A. carbohydrates B. minerals C. proteins D. glucose E. lipids

B. minerals *Minerals are inorganic.

Carbon dioxide functions as a greenhouse gas because it _____. A. creates moist, humid environments similar to a greenhouse B. traps heat that has been radiated from Earth similar to the way the glass of a greenhouse traps heat C. makes tropical plants grow more rapidly than normal, just like in a greenhouse D. (eventually) makes plants grow year-round, just like in a greenhouse

B. traps heat that has been radiated from Earth similar to the way the glass of a greenhouse traps heat *Correct. Carbon dioxide allows visible light to pass but partially blocks heat.

Consider the food chain of grass → grasshopper → mouse → snake → hawk. About how much of the chemical energy fixed by photosynthesis of the grass (100 percent) is available to the hawk? A. 10 percent B. 0.1 percent C. 0.01 percent D. 60 percent E. 1 percent

C. 0.01 percent

10,000 kcal of producer could support approximately _____ kcal of tertiary consumer. A. 1,000 B. 100 C. 10 D. 1 E. 0

C. 10 *This is the number of kcal of tertiary consumer that could be supported.

What happens to the pH of a glass of water when you blow bubbles into it with a straw? A. The pH increases and then decreases. B. There is no change in pH. C. The pH decreases. D. The pH increases.

C. The pH decreases. *Correct! The CO2 in your breath reacts to form carbonic acid.

How are humans impacting the global water cycle when they pave, convert forest to agriculture, and irrigate that agriculture? A. Precipitation is decreasing on every continent. B. The water table is rising on every continent. C. The water table is dropping on every continent. D. Precipitation is increasing on every continent.

C. The water table is dropping on every continent. *Correct. We are reducing the rate at which water penetrates the soil, and withdrawing more groundwater than is being replenished.

An earthworm that feeds on the remains of plants and animals is acting as a _____. A. tertiary consumer B. primary consumer C. detritivore D. secondary consumer E. producer

C. detritivore *The earthworm is feeding on the remains of dead organisms.

A cow eating grass is an example of a _____. A. producer B. detritivore C. primary consumer D. secondary consumer E. tertiary consumer

C. primary consumer *By feeding on a producer, the cow is acting as a primary consumer.

In an ecosystem, phytoplankton are _____. A. secondary consumers B. tertiary consumers C. producers D. primary consumers E. detritivores

C. producers *Autotrophs, such as phytoplankton, are producers.

Why are atmospheric CO2 concentrations low in the Northern Hemisphere in summer and high in the winter? A. Hotter temperatures reduce the ability of CO2 to remain in the atmosphere. B. More driving occurs during the summer months. C. Atmospheric CO2 concentrations do not vary significantly over the season. D. Photosynthetic activity is increased in the summer relative to the winter.

D. Photosynthetic activity is increased in the summer relative to the winter. *Correct! Seasonal changes in the Northern Hemisphere have impacts on atmospheric CO2.

most primary producers use solar energy via photosynthesis: -plants -phytoplnkton -macroalgae

NPP=GPP - R

NPP=GPP - R

Net primary Productiviy = gross primary productivity - respiration

food web

The complex network of interactions among species in an ecosystem formed by the transfer of energy and nutrients among trophic levels. Consists of many food chains.

Acidification

The ocean becomes more acidic as it absorbs CO2, causing a wide range of consequences, such as the slowing of skeletal growth in corals, and coral bleaching.

Why differences between coast and open ocean?

Two sources of nutrients: runoff from land, and ocean sediments

phenology shifts

the change in the timing of seasonal events such as migration, flowering, hatching, and feeding can result in mismatches between species; such as flower and pollinator

geographic range shifts

the geographic redistribution of species to more favorable climate envelopes can change ecological interactions

Which will have more toxins (eg, DDT or mercury) per gram of tissue, a serving of tuna (eats fish), or a serving of sardines (eats plankton)? Hint: sardines eat lower on the food chain)

tuna *tuna eat large fish which eat small fish (sardines) which eat plankton