Ch 55

In the transition from each trophic level of the food chain to the next trophic level, there is about a __________. (Concept 55.3) SHOW HINT 90% loss of energy 90% gain of energy 2% loss of energy 2% gain of energy 5% loss of energy

90% loss of energy Ecological efficiencies vary greatly among organisms, but they are estimated to be about 5-20%, meaning that 80-95% of the energy in one level is not available to the next.

Why is the transfer of energy in an ecosystem referred to as energy flow, not energy cycling?

Energy passes through an ecosystem, entering as sunlight and leaving as heat. It is not recycled within the ecosystem.

Which of the following is a primary producer? (Concept 55.1) SHOW HINT lions poison ivy humans shrimp detritivores

poison ivy Primary producers are autotrophs.

When you eat an apple, you are a __________. (Concept 55.1) SHOW HINT primary producer carnivore secondary consumer detritivore primary consumer

primary consumer Apple trees are primary producers.

In general, the biomass in an ecosystem will be greatest at the trophic level comprising __________. (Concept 55.3) SHOW HINT carnivores producers secondary consumers herbivores primary consumers

producers Biomass pyramids generally narrow sharply from producers at the base to top-level carnivores at the apex because energy transfers between trophic levels are so inefficient.

Which of the following is a key part of the carbon cycle? (Concept 55.4) SHOW HINT assimilation of atmospheric CO2 by plant photosynthesis return of CO2 to the atmosphere by burning fossil fuels breakdown by decomposers of carbon-containing dead plants and animals return of CO2 to the atmosphere by animal and plant respiration All of the listed responses are correct.

All of the listed responses are correct. Carbon dioxide is released into the atmosphere by cellular respiration in all aerobic organisms and removed by photosynthesis.

Which of the following best describes the base of a pyramid of net production? (Concept 55.3) SHOW HINT It receives energy from the primary, secondary, and tertiary consumers. Its size depends on the energy available from detritivores. It contains the energy left after the producers have died. It contains the energy captured by photosynthesis. It represents the energy available to secondary consumers.

It contains the energy captured by photosynthesis. The trophic level that ultimately supports all others in an ecosystem consists of primary producers, which use light energy to synthesize organic molecules in photosynthesis.

In an ecosystem, what will eventually happen to all incoming energy? (Concept 55.1) SHOW HINT It will be used in photosynthesis. It will be dissipated into space as heat. It will be transferred to the decomposers. It will be transferred from one trophic level to the next. None of the listed responses is correct.

It will be dissipated into space as heat. Solar radiation is the ultimate energy source for most ecosystems, and respiratory heat loss is the ultimate sink.

Use the second law of thermodynamics to explain why an ecosystem's energy supply must be continually replenished (see Concept 8.1).

The second law states that in any energy transfer or transformation, some of the energy is dissipated to the surroundings as heat. For the ecosystem to remain intact, this "escape" of energy from the ecosystem must be offset by the continuous influx of solar radiation.

Based on the law of conservation of energy, ecosystem ecologists can make which of the following assertions? (Concept 55.1) SHOW HINT Photosynthetic organisms can convert approximately 1% of the solar energy they receive into organic molecules. Elements are not lost on a global scale. Approximately 10% of energy is transferred from one trophic level to the next. The total amount of energy stored in organic molecules plus the amounts reflected and dissipated as heat must equal the total solar energy intercepted by the Earth. All of the listed responses are correct.

The total amount of energy stored in organic molecules plus the amounts reflected and dissipated as heat must equal the total solar energy intercepted by the Earth. Although the total energy budget of the Earth is a very difficult thing to measure, this assertion is true according to the law of conservation of energy.

Which of the following is an ecosystem? (Concept 55.0) SHOW HINT the water, temperature, rocks, and other abiotic components of the aquarium all of the organisms living in your aquarium and the abiotic factors with which they interact all of the organisms living in your aquarium all of the angelfish in your aquarium all of the angelfish on the planet

all of the organisms living in your aquarium and the abiotic factors with which they interact Communities are composed of abiotic and biotic factors.

Photosynthetic organisms are called __________. (Concept 55.1) SHOW HINT herbivores autotrophs carnivores heterotrophs consumers

autotrophs Autotrophs are generally photosynthetic organisms that use light energy to synthesize sugars and other organic compounds.

The main decomposers in an ecosystem are __________. (Concept 55.1) SHOW HINT fungi and prokaryotes prokaryotes and plants plants and animals plants and fungi prokaryotes and animals

fungi and prokaryotes Fungi and prokaryotes are the groups most involved in the conversion of organic compounds to inorganic nutrients.

The gas carbon dioxide (CO2) is an input to photosynthesis and an end product of cellular respiration. end product of photosynthesis. input to cellular respiration. end product of both photosynthesis and cellular respiration.

input to photosynthesis and an end product of cellular respiration. In photosynthesis, energy from light is captured and converted to chemical energy that is stored in sugar and other organic molecules. Photosynthesis also generates oxygen. The oxygen and organic molecules produced in photosynthesis are used by the mitochondria of eukaryotes (including plants and algae) as fuel for cellular respiration. Respiration breaks this fuel down, generating ATP. The waste products of this type of respiration, carbon dioxide and water, are the raw materials for photosynthesis.

The biggest difference between the flow of energy and the flow of chemical nutrients in an ecosystem is that __________. (Concept 55.1) SHOW HINT energy is recycled, but nutrients are not nutrients are recycled, but energy is not organisms always need nutrients, but they don't always need energy organisms always need energy, but they don't always need nutrients the amount of energy is much greater than the amount of nutrients

nutrients are recycled, but energy is not Chemical nutrients can be recycled within ecosystems through biogeochemical cycles. Energy is lost from an ecosystem in the form of heat.

In ecosystems, organisms at the highest trophic levels usually contain less collective biomass than the organisms at lower trophic levels because __________. (Concept 55.3) SHOW HINT top-level predators use so much energy to catch their food organisms are inefficient at converting the energy they consume into biomass producers (for example, plants) tend to be heavier than consumers (for example, birds) biomass shrinks as it rises most of the solar energy hitting Earth is reflected back into space

organisms are inefficient at converting the energy they consume into biomass Ecological efficiencies vary greatly among organisms, but they are estimated to be about 5-20%, meaning that 80-95% of the energy in one level is not available to the next

In the food web shown here, which of the following lists includes a primary producer, a primary consumer, and a secondary consumer? Diagram shows organisms connected to other organisms with arrows. From the bottom, phytoplankton lead to copepods and krill, which both lead to fishes which lead to leopard seals which lead to smaller toothed whales. Diagram shows organisms connected to other organisms with arrows. From the bottom, phytoplankton lead to krill and copepods. Krill lead to carnivorous plankton, fishes, birds, crabeater seals, and baleen whales. Copepods lead to krill, carnivorous plankton, fishes, squids, and birds. Carnivorous plankton lead to fishes, birds, and squids. Birds lead to leopard seals and smaller toothed whales. Fishes lead to birds, leopard seals, sperm whales, squids, and elephant seals. Squids lead to fishes, leopard seals, birds, smaller toothed whales, elephant seals, and sperm whales. Crabeater seals lead to smaller toothed whales. Leopard seals lead to smaller toothed whales. Elephant seals lead to smaller toothed whales. phytoplankton; copepods; fishes phytoplankton; carnivorous plankton; birds carnivorous plankton; copepods; leopard seals carnivorous plankton; squids; leopard seals

phytoplankton; copepods; fishes Most primary producers are photosynthetic organisms such as plants, multicellular algae, and the phytoplankton shown in this food web. Organisms that feed directly on primary producers are called primary consumers, such as the krill and copepods shown in this food web. Organisms that feed on primary consumers are called secondary consumers; in this food web, seven groups of secondary consumers are shown, including fishes, baleen whales, crabeater seals, and carnivorous plankton.

Which of the following organisms is incorrectly paired with its trophic level? cyanobacterium—primary producer grasshopper—primary consumer zooplankton—primary producer fungus—detritivore

zooplankton—primary producer