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Questions and Answers
What term describes the amount of chemical energy in consumers’ food converted to new biomass during a given period?
What term describes the amount of chemical energy in consumers’ food converted to new biomass during a given period?
What fraction of total plant production do herbivores globally consume?
What fraction of total plant production do herbivores globally consume?
When a caterpillar feeds on a leaf, what portion of the potential energy in the leaf is used for secondary production (growth)?
When a caterpillar feeds on a leaf, what portion of the potential energy in the leaf is used for secondary production (growth)?
What ultimately happens to the energy in feces after it is consumed by decomposers?
What ultimately happens to the energy in feces after it is consumed by decomposers?
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What is the main purpose of the energy stored by herbivores as biomass?
What is the main purpose of the energy stored by herbivores as biomass?
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What happens to the energy used for the caterpillar's respiration?
What happens to the energy used for the caterpillar's respiration?
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What is measured to determine the efficiency of animals as energy transformers?
What is measured to determine the efficiency of animals as energy transformers?
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What keeps most of the ecosystem’s production integrated rather than completely consumed by herbivores?
What keeps most of the ecosystem’s production integrated rather than completely consumed by herbivores?
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What is the dry mass of primary producers in a typical trophic level?
What is the dry mass of primary producers in a typical trophic level?
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Why can primary consumers in certain aquatic ecosystems have a larger biomass than their primary producers?
Why can primary consumers in certain aquatic ecosystems have a larger biomass than their primary producers?
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What is the dry mass of secondary consumers according to the trophic levels presented?
What is the dry mass of secondary consumers according to the trophic levels presented?
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What implication does energy flow through ecosystems have on human dietary choices?
What implication does energy flow through ecosystems have on human dietary choices?
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What happens to the relationship between biomass and energy in ecosystems with inverted pyramids?
What happens to the relationship between biomass and energy in ecosystems with inverted pyramids?
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What constitutes assimilation in an organism?
What constitutes assimilation in an organism?
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How does production efficiency differ from respiration in organisms?
How does production efficiency differ from respiration in organisms?
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Which group of organisms typically demonstrates the highest production efficiency?
Which group of organisms typically demonstrates the highest production efficiency?
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What is trophic efficiency?
What is trophic efficiency?
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Why is trophic efficiency always lower than production efficiency?
Why is trophic efficiency always lower than production efficiency?
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What percentage of energy is typically transferred from primary producers to primary consumers?
What percentage of energy is typically transferred from primary producers to primary consumers?
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What factor most limits the number of top-level carnivores in an ecosystem?
What factor most limits the number of top-level carnivores in an ecosystem?
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What characterizes an energy pyramid?
What characterizes an energy pyramid?
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Which type of ecosystem is likely to have an inverted biomass pyramid?
Which type of ecosystem is likely to have an inverted biomass pyramid?
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When calculating net primary production, what factors must be considered?
When calculating net primary production, what factors must be considered?
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Understanding energy flow in ecosystems helps explain why food webs typically include only a limited number of trophic levels. What is this number?
Understanding energy flow in ecosystems helps explain why food webs typically include only a limited number of trophic levels. What is this number?
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Which variable describes the energy captured by primary producers from solar radiation?
Which variable describes the energy captured by primary producers from solar radiation?
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In a salt marsh, how is energy density typically measured in biomass?
In a salt marsh, how is energy density typically measured in biomass?
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What role do decomposers play in ecosystems?
What role do decomposers play in ecosystems?
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Which of the following factors most affects the rate of decomposition in an ecosystem?
Which of the following factors most affects the rate of decomposition in an ecosystem?
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In which ecosystem is organic material likely to decompose the fastest?
In which ecosystem is organic material likely to decompose the fastest?
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What happens to the atoms in an organism's body after it dies?
What happens to the atoms in an organism's body after it dies?
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What conclusion can be drawn about the relationship between temperature and litter decomposition rates?
What conclusion can be drawn about the relationship between temperature and litter decomposition rates?
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What type of organism primarily feeds on detritus in an ecosystem?
What type of organism primarily feeds on detritus in an ecosystem?
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Why is the decomposition process crucial for plant growth?
Why is the decomposition process crucial for plant growth?
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What evidence supports that decomposition rates differ across ecosystems in Canada?
What evidence supports that decomposition rates differ across ecosystems in Canada?
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What is the primary form of phosphorus that plants absorb for use in biological processes?
What is the primary form of phosphorus that plants absorb for use in biological processes?
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What is the role of wind-blown dust in the phosphorus cycle?
What is the role of wind-blown dust in the phosphorus cycle?
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Which human activity has significant effects on the nitrogen cycle through reactive nitrogen gas release?
Which human activity has significant effects on the nitrogen cycle through reactive nitrogen gas release?
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What process primarily contributes to the addition of inorganic phosphorus to soil?
What process primarily contributes to the addition of inorganic phosphorus to soil?
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What was the effect of deforestation in the Hubbard Brook Experimental Forest on water runoff?
What was the effect of deforestation in the Hubbard Brook Experimental Forest on water runoff?
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What mineral demonstrated a significant increase in concentration in runoff after deforestation in the Hubbard Brook study?
What mineral demonstrated a significant increase in concentration in runoff after deforestation in the Hubbard Brook study?
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Which statement about the phosphorus cycle is accurate?
Which statement about the phosphorus cycle is accurate?
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What is a consequence of nutrient cycling in the Hubbard Brook Experimental Forest as identified by researchers?
What is a consequence of nutrient cycling in the Hubbard Brook Experimental Forest as identified by researchers?
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What percentage of water added to the Hubbard Brook ecosystem is estimated to exit through the stream?
What percentage of water added to the Hubbard Brook ecosystem is estimated to exit through the stream?
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Why is the flow of nutrients controlled primarily by plants in forest ecosystems?
Why is the flow of nutrients controlled primarily by plants in forest ecosystems?
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Which process does NOT contribute significantly to the movement of phosphorus in the atmosphere?
Which process does NOT contribute significantly to the movement of phosphorus in the atmosphere?
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What is one of the largest reservoirs of phosphorus in the biosphere?
What is one of the largest reservoirs of phosphorus in the biosphere?
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What is the primary factor for the variations in nitrate concentration in deforested versus control watersheds in the Hubbard Brook study?
What is the primary factor for the variations in nitrate concentration in deforested versus control watersheds in the Hubbard Brook study?
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Which factors, besides temperature, might influence decomposition rates in different forest ecosystems?
Which factors, besides temperature, might influence decomposition rates in different forest ecosystems?
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In tropical rain forests, where is a majority of the ecosystem's nutrients stored?
In tropical rain forests, where is a majority of the ecosystem's nutrients stored?
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What is a primary consequence of slow decomposition rates in temperate forests?
What is a primary consequence of slow decomposition rates in temperate forests?
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What role does peat play in the decomposition process within certain ecosystems?
What role does peat play in the decomposition process within certain ecosystems?
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Which factors can inhibit decomposition in swamp sediments?
Which factors can inhibit decomposition in swamp sediments?
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How do biogeochemical cycles differ for gaseous elements compared to heavier elements?
How do biogeochemical cycles differ for gaseous elements compared to heavier elements?
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What connection exists between reservoir A and reservoir B regarding organic materials?
What connection exists between reservoir A and reservoir B regarding organic materials?
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Which of the following elements is primarily cycled globally within ecosystems?
Which of the following elements is primarily cycled globally within ecosystems?
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Which process is primarily responsible for moving inorganic materials from reservoir D to reservoir C?
Which process is primarily responsible for moving inorganic materials from reservoir D to reservoir C?
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What is primarily illustrated by nutrient cycle diagrams?
What is primarily illustrated by nutrient cycle diagrams?
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What happens to organic materials that are not assimilated by living organisms?
What happens to organic materials that are not assimilated by living organisms?
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Which condition is most likely to enhance decomposition in an ecosystem?
Which condition is most likely to enhance decomposition in an ecosystem?
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Why do aquatic ecosystems have a distinct nutrient cycling process?
Why do aquatic ecosystems have a distinct nutrient cycling process?
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Which process predominantly drives the water cycle in terrestrial ecosystems?
Which process predominantly drives the water cycle in terrestrial ecosystems?
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In the carbon cycle, which is considered the largest reservoir of carbon?
In the carbon cycle, which is considered the largest reservoir of carbon?
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Which factor primarily limits nitrogen availability to terrestrial plants?
Which factor primarily limits nitrogen availability to terrestrial plants?
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What is a crucial biological process for removing carbon dioxide from the atmosphere?
What is a crucial biological process for removing carbon dioxide from the atmosphere?
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Which human activity has significantly impacted the global nitrogen cycle?
Which human activity has significantly impacted the global nitrogen cycle?
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Primary production rates in ecosystems are heavily influenced by the availability of which resource?
Primary production rates in ecosystems are heavily influenced by the availability of which resource?
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Which statement accurately describes the role of decomposition in the carbon cycle?
Which statement accurately describes the role of decomposition in the carbon cycle?
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What is the main driving force for evaporation in the water cycle?
What is the main driving force for evaporation in the water cycle?
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Which of the following is a significant form of nitrogen that plants can assimilate?
Which of the following is a significant form of nitrogen that plants can assimilate?
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Which process contributes to carbon emissions through human activity?
Which process contributes to carbon emissions through human activity?
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What role do phytoplankton play in the carbon cycle?
What role do phytoplankton play in the carbon cycle?
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How do terrestrial plants contribute to the water cycle?
How do terrestrial plants contribute to the water cycle?
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What is a major human-induced source of additional carbon in the atmosphere?
What is a major human-induced source of additional carbon in the atmosphere?
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In which reservoir is most of the Earth's freshwater stored?
In which reservoir is most of the Earth's freshwater stored?
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Study Notes
Secondary Production in Ecosystems
- Secondary production refers to the conversion of chemical energy from food into biomass by consumers during a specific timeframe.
- Herbivores, or primary consumers, typically consume only about one-sixth of total plant production in ecosystems.
Energy Transfer and Production Efficiency
- A caterpillar utilizes only one-sixth of the energy from the leaves it eats for growth, with the rest used in respiration or lost in feces.
- Energy from feces can be temporarily retained in the ecosystem but is mostly lost as heat when consumed by decomposers.
- Production efficiency is determined by the percentage of energy from assimilated food saved for growth and reproduction rather than lost to respiration.
- Birds and mammals have low production efficiencies (around 4-30%), while fishes have efficiencies of 10-20%, and insects and microorganisms exceed 40%.
Trophic Efficiency and Energy Flow
- Trophic efficiency is the percentage of production that transfers from one trophic level to another, always lower than production efficiency due to losses at each stage.
- Average trophic efficiencies range from 5% to 20%, meaning a significant amount of energy (approximately 80%-95%) is lost between levels.
- Example: If 10% of energy is transferred from primary producers to primary consumers, only 1% of net primary production is available to secondary consumers.
Energy Flow in Salt Marsh Ecosystem
- John Teal’s study on a salt marsh showed the energy flow among producers, consumers, and decomposers, measuring solar radiation and biomass.
- Solar energy incorporated: Gross primary production at 34,580 kilocalories; Net primary production at 6,585 kilocalories.
- Detritus leaving the marsh accounted for 3,671 kilocalories; significant losses occur through respiration of both producers and consumers.
Implications of Energy Loss
- The loss of energy along the food chain limits the number of top-level carnivores an ecosystem can support, usually capping food chains at around four to five trophic levels.
- An energy pyramid visually represents these losses, showing how net production decreases at higher trophic levels.
Biomass Distribution
- Biomass pyramids typically demonstrate decreased biomass from primary producers to top-level consumers, illustrating inefficiencies in energy transfer.
- Inverted biomass pyramids may occur in aquatic systems where rapid consumption and replacement by phytoplankton support larger populations of primary consumers (zooplankton).
Human Consumption and Energy Efficiency
- Consuming meat is less efficient than obtaining energy directly from plants, highlighting food conversion inefficiencies.
- A shift towards plant-based diets could better allocate resources and require less land to support human populations globally.
Ecosystem Energy and Nutrient Cycling
- Ecosystems primarily rely on solar energy, while essential chemical elements are limited and need continuous recycling.
- Organisms regularly assimilate nutrients, releasing waste and returning atoms to the atmosphere, water, or soil upon death.
- Decomposers are key heterotrophs that break down organic matter, liberating nutrients for plants and autotrophs to utilize.
Decomposition Rates
- Decomposition rates vary with environmental factors: temperature, moisture, nutrient availability.
- In warmer ecosystems, decomposers function more efficiently, with litter decomposing significantly faster in tropical rainforests than in temperate forests.
- On average, organic material decomposes in a few months to a few years in tropical rainforests; in temperate regions, it can take four to six years.
Impact of Temperature on Decomposition
- Research conducted by the Canadian Forest Service demonstrated a fourfold increase in litter decomposition rates in warmer ecosystems compared to colder ones.
- Conditions that hinder decomposition include excessive dryness or saturation, particularly in cold, wet areas such as peatlands, leading to significant organic matter storage.
Biogeochemical Cycles
- Nutrient cycling involves both biotic (living) and abiotic (non-living) components, distinguished as global and local cycles.
- Gaseous elements like carbon, oxygen, sulfur, and nitrogen exist globally in the atmosphere; others like phosphorus and potassium cycle more locally.
- Nutrients in living organisms and detritus are transferred to other organisms through food webs and decomposition processes.
Water Cycle
- Water is essential for life, influencing ecosystem processes like primary production and decomposition.
- The oceans contain around 97% of the world's water, with glaciers and polar ice caps holding approximately 2%, and the remaining 1% found in lakes, rivers, and groundwater.
- Key processes in the water cycle include evaporation, condensation, precipitation, and plant transpiration.
Carbon Cycle
- Carbon is a vital building block in organic molecules and is cycled through processes like photosynthesis by plants, cellular respiration by consumers, and fossil fuel combustion.
- Major carbon reservoirs include fossil fuels, soils, ocean sediments, and atmospheric CO2, where geological time scales play a role in carbon storage dynamics.
Nitrogen Cycle
- Nitrogen is crucial for amino acids, proteins, and nucleic acids, with plants utilizing forms like ammonium and nitrate while animals require organic forms.
- Natural nitrogen fixation occurs through bacteria and processes such as lightning. Human activity has increased nitrogen inputs through fertilizers and agricultural practices.
Phosphorus Cycle
- Phosphorus is vital for nucleic acids, ATP, and skeletal structures; its most significant form is phosphate, which plants absorb.
- Phosphorus accumulates primarily in sedimentary rocks, with localized recycling due to soil retention and limited atmospheric movement.
Hubbard Brook Experimental Forest Case Study
- Research has been ongoing since 1963 on nutrient cycling in the Hubbard Brook Experimental Forest, focusing on how vegetation affects drainage and nutrient loss.
- After clear-cutting a watershed, water and nutrient runoff increased markedly, particularly in the concentration of nitrate, leading to concerns about drinking water safety.
- Internal cycling was found to conserve most minerals, while deforestation led to dramatic losses in nutrient retention, highlighting the role of vegetation in ecosystem productivity and nutrient control.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your understanding of the secondary production in ecosystems. This quiz covers the transfer of energy from primary producers to herbivores and highlights the efficiency of energy conversion in food webs. Explore the dynamics of food consumption and biomass production in ecological systems.
