BSC 2011 Ch 55

A study of metabolic rates in a terrestrial community showed that the energy released by respiration exceeded the energy captured in photosynthesis. Which of the following situations is most likely?

Community biomass is decreasing.

Identifying trophic levels in a food web Use the following diagram of a food web to sort the items below.

Detritus dead animal rotting log Primary producer living maple leaves Primary consumer or decomposer maggots fungus cricket Secondary consumer earthworm millipede Tertiary consumer Both secondary and tertiary consumer robin alligator lizard

Detritivores are _________.

heterotrophs

The law of conservation of mass is important in ecology because _________.

it allows scientists to determine the gain or loss of a chemical element in an ecosystem

What is the main abiotic reservoir for elements involved in local biogeochemical cycles, such as calcium and phosphorus?

Soil

The phosphorus cycle lacks a(n) __________ component.

atmospheric

Calculating trophic efficiency Calculate the trophic efficiency from each trophic level to the next for the pyramid of productivity (biomass pyramid) shown below.

14.9,10.6,12.0 %

What percentage of the solar energy that reaches the marsh is incorporated into gross primary production?

5.8% The answer is the gross grass production divided by the solar radiation = 34,580 ÷ 600,000 = 0.058 or 5.8%.

What is represented by the distance between two vertical white gridlines on this graph? A 500-fold increase in net primary productivity 500 g/m2/year Each line represents a different ecosystem. A doubling of net primary productivity

500 g/m2/year

Which of the following is an ecosystem?

All of the organisms living in your aquarium and the abiotic factors with which they interact

The net primary productivity of cultivated land is most similar to the net primary productivity of which ecosystem? Boreal forest (taiga) Temperate grassland Tropical rain forest Temperate deciduous forest

Boreal forest (taiga) Temperate grassland

Use the following diagram of a hypothetical food web to answer the question. The arrows represent the transfer of energy between the various trophic levels. Which letter represents an organism that could only be a primary consumer?

C

How do iron levels affect phytoplankton populations in a marine ecosystem?

Iron stimulates the growth of cyanobacteria, which convert atmospheric N2 to nitrogenous minerals, stimulating the growth of phytoplankton.

The net primary productivity of an estuary ecosystem is roughly 12 times the net primary productivity of the open ocean. Supported Not supported Cannot be determined from this graph

Supported

An organism's "trophic level" refers to _____. An organism's "trophic level" refers to _____. the rate at which it uses energy its food source the intensity of its competition with other species where it lives whether it is early or late in ecological succession

its food source

A measure of the total biomass accumulation during a given period of time is called the _________.

net ecosystem production

The direct product of nitrogen fixation is __________.

NH3

Based on the food web diagram, label the following statements as true or false. Drag "True" or "False" to the end of each statement. Phytoplankton are primary consumers. Squids are secondary consumers. Squids are tertiary consumers. Leopard seals are quaternary consumers

Phytoplankton are primary consumers. False Squids are secondary consumers. True Squids are tertiary consumers. True Leopard seals are quaternary consumers. True

Primary producers are _________.

autotrophs

Which of the following statements is true?

Over oceans, evaporation exceeds precipitation.

The longest food chain in this food web includes nine groups of organisms. Which of the following groups is included in that food chain? elephant seals sperm whales birds crabeater seals

birds

If all of the detritus leaving the marsh is plant material, what percentage of all net primary production leaves the marsh as detritus each year?

56% The answer is the amount of energy in detritus leaving the marsh divided by the net grass production = 3,671 ÷ 6,585 = 0.56 or 56%.

Local conditions such as heavy rainfall or the removal of plants may limit the amount of nitrogen, phosphorus, or calcium available to a particular ecosystem, but the amount of carbon available to the system is seldom a problem. Why?

Many nutrients come from the soil, but carbon comes from the air.

In a working ecosystem such as the arctic tundra, all of the following exist except _______.

a reduction in the competition for resources

In an ecosystem, all incoming energy will eventually be __________.

dissipated into space as heat

Eutrophication in lakes is frequently the direct result of __________.

nutrient enrichment such as nitrate and phosphate runoffs from land

The main decomposers in an ecosystem are __________.

fungi and prokaryotes

What percentage of the solar energy that reaches the marsh is incorporated into net primary production?

1.1% The answer is the net grass production divided by the solar radiation = 6,585 ÷ 600,000 = 0.011 or 1.1%.

How much energy is lost as respiration by the insect population?

224 kcal/(m2 • yr) The energy lost by insects as respiration is the gross insect production minus the net insect production = 305 kcal/(m2 • yr) - 81 kcal/(m2 • yr) = 224 kcal/(m2 • yr).

Most of the sunlight that reaches Earth __________.

is not captured for use by living things

Which of the following statements is supported by the trophic relationships shown in the diagram?

Squids eat fishes.

According to this graph, algal beds and coral reefs have the highest net primary productivity. Supported Not supported Cannot be determined from this graph

Supported

Five different baleen whale species are endangered and may go extinct. What would be the most likely effect of removing all baleen whales from this food web? The krill population would increase. The bird population would decrease. The crabeater seal population would decrease. Sperm whales would also go extinct.

The krill population would increase.

The biomass of cultivated land approximately equals the biomass of temperate grassland. Supported Not supported Cannot be determined from this graph.

Cannot be determined from this graph.

Deforestation of a watershed _______.

dramatically increases the flow of water and minerals out of the watershed

The global hydrologic cycle supports a net flow of atmospheric water vapor __________.

from the oceans to land

A measure of the total primary production in an ecosystem is called the _________.

gross primary production

A measure of production that is calculated by subtracting autotrophic respiration from all primary production in an ecosystem is called _________.

net primary production

The biggest difference between the flow of energy and the flow of chemical nutrients in an ecosystem is that __________.

nutrients are recycled, but energy is not

Important biogeochemical cycles in ecosystems include all of the following except the ________ cycle.

potassium

The percentage of energy stored in assimilated food that is not used for respiration is the _________.

production efficiency

An example of restoration ecology is ________.

restoring seaweed and seagrass beds of fish and shellfish nurseries

Which trophic levels do fishes occupy in this food web? primary producers primary consumers secondary consumers tertiary consumers quaternary consumers

secondary consumers tertiary consumers quaternary consumers

The amount of chemical energy in a consumer's food that is converted to its own new biomass over a period of time is called __________.

secondary production

Which of the following groups can be quaternary consumers in this food web? crabeater seals carnivorous plankton sperm whales baleen whales

sperm whales

The percentage of production transferred from one trophic level to the next-higher level is called ________.

trophic efficiency

Increased rates of decomposition occur in ________ ecosystems.

tropical

Biological augmentation is a process that _________.

uses organisms to add essential materials to a degraded ecosystem

Bioremediation is a process that _________.

uses organisms to detoxify polluted ecosystems

The carbon cycle describes the cycling of carbon between Earth's biotic (living) and abiotic (nonliving) reservoirs. Identify the major reservoirs and processes in the carbon cycle by labeling the diagram below. Drag the labels to their appropriate locations on the diagram of the carbon cycle. First, drag the blue labels to the blue targets to identify the reservoirs in the carbon cycle. Then drag the pink labels to the pink targets to identify the processes in the carbon cycle.

A. CO2 in atmosphere B. Photosynthesis on land C. Photosynthesis in ocean D. Cellular respiration E. Plants F. Burning fossil fuels G. Consumers H. Decomposers

What do the bars on this graph represent? The solar energy available to each ecosystem as determined by its geographic location. The amount of solar energy converted to chemical energy in organic compounds for a given area per year. The percentage of Earth's total primary productivity contributed by various ecosystems. The average amount of solar energy absorbed by various ecosystems.

The amount of solar energy converted to chemical energy in organic compounds for a given area per year.

Suppose that humans increase their consumption of Antarctic fishes, causing a significant reduction in the size of fish populations. What would be the most likely effect of a reduction in the size of Antarctic fish populations? (Drag the terms on the left to the appropriate blanks in the sentences on the right. Terms may be used once, more than once, or not at all.) The carnivorous plankton population would . The elephant seal population would . The sperm whale population would

The carnivorous plankton population would increase. The elephant seal population would decrease. The sperm whale population would decrease.

Analyzing energy flow Which of the following statements about energy flow are true? Select the four statements that are true. -Animals that produce their own body heat and maintain a high body temperature are likely to be less efficient at converting food into biomass than are animals that do not regulate their body temperature. -If the lowest trophic level of an ecosystem--the primary producers--contains 1,200 grams of biomass per square meter, it is reasonable to expect the secondary consumer level to contain about 12 grams of biomass per square meter. -In a trophic pyramid, biomass represents chemical energy. -Energy used in the production of offspring is available to higher trophic levels. -Energy spent on cellular respiration is available to higher trophic levels. -Autotrophs typically capture about 90% of the available energy from the sun through photosynthesis. -Energy contained in feces is available to higher trophic levels.

-Animals that produce their own body heat and maintain a high body temperature are likely to be less efficient at converting food into biomass than are animals that do not regulate their body temperature. -If the lowest trophic level of an ecosystem--the primary producers--contains 1,200 grams of biomass per square meter, it is reasonable to expect the secondary consumer level to contain about 12 grams of biomass per square meter. -In a trophic pyramid, biomass represents chemical energy. -Energy used in the production of offspring is available to higher trophic levels.

The carbon cycle is one of many biogeochemical cycles on Earth. Can you identify the main features of a biogeochemical cycle and show how the carbon cycle exhibits these features? Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Not all terms will be used.

1. In a biogeochemical cycle, a chemical element spends time in different places, called reservoirs. 2. As a chemical element moves through a biogeochemical cycle, it moves between "bio" and "geo." The "bio" in biogeochemical refers to biotic reservoirs, or living organisms. 3. The "geo" in biogeochemical refers to Earth--specifically, to the abiotic reservoirs where a chemical element can be found. 4. In the terrestrial carbon cycle, the abiotic reservoir from which living organisms directly obtain their carbon is the atmosphere. 5. Carbon moves from an abiotic reservoir to living organisms during the process of photosynthesis. 6. Carbon moves from living organisms to an abiotic reservoir during the process of cellular respiration.

How much energy is lost by primary producers as respiration in this ecosystem?

27,995 kcal/(m2 • yr) The energy lost by primary producers as respiration is the gross grass production minus the net grass production = 34,580 kcal/(m2 • yr) - 6,585 kcal/(m2 • yr) = 27,995 kcal/(m2 • yr).

Which of the activities listed below could help limit global warming by slowing the increase in atmospheric carbon dioxide levels? limiting soil erosion so organic matter takes longer to decompose replacing fossil fuels with nuclear energy using more electrical appliances and cars choosing a fuel-efficient car, or bicycling to school or work cutting down forests to build houses burning vegetation to clear land for agriculture

choosing a fuel-efficient car, or bicycling to school or work limiting soil erosion so organic matter takes longer to decompose replacing fossil fuels with nuclear energy