p.8
Ecological Pyramids: Number, Biomass, and Energy
What does the pyramid of numbers in a grassland ecosystem illustrate?
Only three top carnivores are supported by nearly 6 million plants.
p.1
Types of Ecosystems: Terrestrial and Aquatic
What are some examples of terrestrial ecosystems?
Forest, grassland, and desert.
p.9
Interactions Between Biotic and Abiotic Components
What does a trophic level represent?
A functional level, not a specific species.
p.9
Interactions Between Biotic and Abiotic Components
How can a species occupy more than one trophic level?
By consuming different types of food at different levels, e.g., a sparrow as both a primary and secondary consumer.
p.16
Definition and Structure of Ecosystems
What are biotic components in an ecosystem?
Producers, consumers, and decomposers.
p.14
Nutrient Cycling: Gaseous and Sedimentary Cycles
What are some sources that release CO2 into the atmosphere?
Burning of wood, forest fires, combustion of organic matter, fossil fuel, and volcanic activity.
p.3
Ecosystem Productivity: GPP and NPP
What factors influence primary productivity?
Plant species, environmental factors, availability of nutrients, and photosynthetic capacity.
p.8
Ecological Pyramids: Number, Biomass, and Energy
What does the apex of each ecological pyramid represent?
Tertiary or top-level consumers.
p.13
Nutrient Cycling: Gaseous and Sedimentary Cycles
What is the standing state in an ecosystem?
The amount of nutrients present in the soil at any given time.
p.3
Ecosystem Productivity: GPP and NPP
How is productivity expressed?
In terms of weight (g m–2) or energy (kcal m–2).
p.2
Interactions Between Biotic and Abiotic Components
What regulates the function of a pond ecosystem?
Solar input, temperature cycles, day-length, and other climatic conditions.
p.3
Ecosystem Productivity: GPP and NPP
What are the two types of primary productivity?
Gross primary productivity (GPP) and net primary productivity (NPP).
p.10
Ecological Succession: Primary and Secondary
What is primary succession?
Succession that starts in an area with no living organisms, like bare rock.
p.11
Ecological Succession: Primary and Secondary
What are the two types of plant succession based on habitat?
Hydrarch (wet areas) and xerarch (dry areas).
p.3
Ecosystem Productivity: GPP and NPP
What is secondary productivity?
The rate of formation of new organic matter by consumers.
p.6
Energy Flow in Ecosystems
What role does the detritus food chain play in aquatic ecosystems?
It is the major conduit for energy flow.
p.4
Decomposition Processes and Importance
What is humus?
A dark colored amorphous substance that is highly resistant to microbial action and undergoes decomposition slowly.
p.8
Ecological Pyramids: Number, Biomass, and Energy
What are the three types of ecological pyramids studied?
(a) Pyramid of number; (b) Pyramid of biomass; (c) Pyramid of energy.
p.8
Ecological Pyramids: Number, Biomass, and Energy
What does the pyramid of biomass show at higher trophic levels?
A sharp decrease in biomass.
p.7
Energy Flow in Ecosystems
What does the 10 percent law state regarding energy transfer?
Only 10 percent of energy is transferred to each trophic level from the lower level.
p.9
Energy Flow in Ecosystems
Why is the pyramid of energy always upright?
Because energy is always lost as heat when flowing from one trophic level to the next.
p.3
Ecosystem Productivity: GPP and NPP
How is net primary productivity (NPP) calculated?
NPP = GPP - R (respiration losses).
p.1
Energy Flow in Ecosystems
What relationships are created within ecosystems due to energy flows?
Cycles, chains, and webs.
p.4
Decomposition Processes and Importance
How does the presence of lignin and chitin in detritus affect decomposition rate?
It slows down the decomposition rate.
p.7
Ecological Pyramids: Number, Biomass, and Energy
What is the standing crop?
The mass of living material at a particular time in a trophic level.
p.13
Nutrient Cycling: Gaseous and Sedimentary Cycles
What is nutrient cycling?
The movement of nutrient elements through various components of an ecosystem.
p.10
Ecological Succession: Primary and Secondary
What is a climax community?
A community that is in near equilibrium with the environment.
p.3
Ecosystem Productivity: GPP and NPP
What is biomass in an ecosystem?
Organic matter produced per unit area over time by plants during photosynthesis.
p.16
Definition and Structure of Ecosystems
What are abiotic components?
Inorganic materials such as air, water, and soil.
p.5
Energy Flow in Ecosystems
What is the flow of energy in an ecosystem?
Unidirectional flow from the sun to producers and then to consumers.
p.16
Ecosystem Productivity: GPP and NPP
What is the difference between GPP and NPP?
GPP is the total production of organic matter, while NPP is the remaining biomass after utilization by producers.
p.16
Nutrient Cycling: Gaseous and Sedimentary Cycles
What is nutrient cycling?
The storage and movement of nutrient elements through various components of the ecosystem.
p.17
Nutrient Cycling: Gaseous and Sedimentary Cycles
What are the salient features of carbon cycling in an ecosystem?
Involves processes like photosynthesis, respiration, and decomposition.
p.6
Ecological Pyramids: Number, Biomass, and Energy
What do producers, herbivores, and carnivores represent in the trophic levels?
Producers are the first level, herbivores are the second, and carnivores are the third.
p.8
Ecological Pyramids: Number, Biomass, and Energy
What do ecological pyramids express?
Relationships at different trophic levels in terms of number, biomass, or energy.
p.8
Ecological Pyramids: Number, Biomass, and Energy
What does the base of each ecological pyramid represent?
The producers or the first trophic level.
p.7
Decomposition Processes and Importance
What is detritus?
Dead biomass that serves as an energy source for decomposers.
p.2
Definition and Structure of Ecosystems
What are the two main components of the environment studied in ecosystems?
Abiotic and biotic components.
p.9
Ecological Pyramids: Number, Biomass, and Energy
What must calculations of energy content, biomass, or numbers include?
All organisms at that trophic level.
p.11
Ecological Succession: Primary and Secondary
What is secondary succession?
It begins in areas where natural biotic communities have been destroyed, such as abandoned farmland or burned forests.
p.16
Definition and Structure of Ecosystems
What is an ecosystem?
A structural and functional unit of nature comprising abiotic and biotic components.
p.13
Nutrient Cycling: Gaseous and Sedimentary Cycles
What regulates the rate of nutrient release into the atmosphere?
Environmental factors like soil, moisture, pH, and temperature.
p.10
Ecological Succession: Primary and Secondary
How long does it generally take for soil to form on bare rock?
Several hundred to several thousand years, depending on the climate.
p.14
Nutrient Cycling: Gaseous and Sedimentary Cycles
How do human activities affect the carbon cycle?
Rapid deforestation and massive burning of fossil fuels increase CO2 release.
p.3
Decomposition Processes and Importance
What is detritus?
Dead plant remains and animal remains, including fecal matter, that serve as raw material for decomposition.
p.15
Ecosystem Services and Their Economic Value
What are the contributions of recreation and nutrient cycling to the total cost of ecosystem services?
Less than 10 percent each.
p.12
Ecological Succession: Primary and Secondary
Does succession in water and on land lead to different climax communities?
No, it proceeds to a similar climax community – the mesic.
p.7
Ecosystem Productivity: GPP and NPP
How is biomass measured for accuracy?
Biomass is more accurately measured in terms of dry weight.
p.10
Ecological Succession: Primary and Secondary
What are sere(s)?
The entire sequence of communities that successively change in a given area.
p.17
Decomposition Processes and Importance
What are common detritivores in our ecosystem?
Earthworms, fungi, and some bacteria.
p.2
Definition and Structure of Ecosystems
What are the autotrophic components in a pond?
Phytoplankton, some algae, and various aquatic plants.
p.16
Definition and Structure of Ecosystems
What are the two main structural features of an ecosystem?
Species composition and stratification.
p.16
Ecosystem Productivity: GPP and NPP
What is primary productivity?
The rate of capture of solar energy or biomass production of producers.
p.11
Ecological Succession: Primary and Secondary
What is the climax community?
A stable community that remains unchanged as long as the environment remains stable.
p.17
Energy Flow in Ecosystems
What is the difference between a grazing food chain and a detritus food chain?
A grazing food chain starts with producers, while a detritus food chain starts with decomposing organic matter.
p.15
Ecosystem Services and Their Economic Value
How does the value of ecosystem services compare to the global gross national product (GNP)?
It is nearly twice the value of the GNP, which is US $18 trillion.
p.6
Interactions Between Biotic and Abiotic Components
What is a food web?
The natural interconnection of food chains.
p.4
Decomposition Processes and Importance
What conditions favor decomposition?
Warm and moist environments.
p.10
Ecological Succession: Primary and Secondary
What does ecological succession refer to?
The gradual and predictable change in species composition of a given area.
p.8
Ecological Pyramids: Number, Biomass, and Energy
What is unique about the inverted pyramid of biomass?
A small standing crop of phytoplankton supports a large standing crop of zooplankton.
p.2
Ecosystem Productivity: GPP and NPP
What are the four basic components of an ecosystem?
Productivity, decomposition, energy flow, and nutrient cycling.
p.2
Decomposition Processes and Importance
What role do decomposers play in a pond ecosystem?
They break down dead matter, releasing nutrients back for reuse by autotrophs.
p.15
Ecosystem Services and Their Economic Value
What are ecosystem services?
Products of ecosystem processes that provide economic, environmental, and aesthetic benefits.
p.14
Nutrient Cycling: Gaseous and Sedimentary Cycles
What is a major natural reservoir of phosphorus?
Rock, in the form of phosphates.
p.5
Energy Flow in Ecosystems
What role do herbivores play in the ecosystem?
They are primary consumers that feed on plants.
p.6
Decomposition Processes and Importance
How do decomposers obtain their energy?
By degrading dead organic matter or detritus.
p.16
Ecological Succession: Primary and Secondary
What characterizes a climax community?
It remains stable as long as the environment remains unchanged.
p.10
Ecological Pyramids: Number, Biomass, and Energy
What is a limitation of ecological pyramids?
They do not account for the same species belonging to multiple trophic levels.
p.2
Definition and Structure of Ecosystems
What does stratification in an ecosystem refer to?
The vertical distribution of different species occupying different levels.
p.5
Energy Flow in Ecosystems
What do plants and photosynthetic bacteria do with solar energy?
They fix the Sun’s radiant energy to make food from simple inorganic materials.
p.10
Ecological Succession: Primary and Secondary
What are seral stages?
The individual transitional communities in ecological succession.
p.11
Ecological Succession: Primary and Secondary
Why is succession faster in secondary succession compared to primary succession?
Because some soil or sediment is already present.
p.9
Ecological Pyramids: Number, Biomass, and Energy
What paradox is observed in the pyramid of biomass in the sea?
The biomass of fishes exceeds that of phytoplankton, resulting in an inverted pyramid.
p.13
Nutrient Cycling: Gaseous and Sedimentary Cycles
Why are nutrients never lost from ecosystems?
Because they are recycled time and again indefinitely.
p.11
Ecological Succession: Primary and Secondary
What is xerarch succession?
Succession that occurs in dry areas, progressing from xeric to mesic conditions.
p.5
Energy Flow in Ecosystems
What are secondary consumers?
Animals that eat primary consumers.
p.16
Decomposition Processes and Importance
What are the three processes involved in decomposition?
Fragmentation of detritus, leaching, and catabolism.
p.14
Nutrient Cycling: Gaseous and Sedimentary Cycles
What is a key difference between the carbon and phosphorus cycles?
Atmospheric inputs of phosphorus through rainfall are much smaller than carbon inputs.
p.17
Decomposition Processes and Importance
What is decomposition?
The process by which organic substances are broken down into simpler organic or inorganic matter.
p.6
Interactions Between Biotic and Abiotic Components
What connects the detritus food chain with the grazing food chain?
Some organisms of the DFC are prey to GFC animals.
p.7
Energy Flow in Ecosystems
What happens to the amount of energy at successive trophic levels?
The amount of energy decreases.
p.4
Decomposition Processes and Importance
What inhibits decomposition?
Low temperature and anaerobiosis.
p.1
Definition and Structure of Ecosystems
What is the biosphere regarded as by many ecologists?
A global ecosystem, composed of all local ecosystems on Earth.
p.10
Ecological Succession: Primary and Secondary
What are the two types of ecological succession?
Primary succession and secondary succession.
p.3
Ecosystem Productivity: GPP and NPP
What does gross primary productivity (GPP) measure?
The rate of production of organic matter during photosynthesis.
p.11
Ecological Succession: Primary and Secondary
What is hydrarch succession?
Succession that occurs in wet areas, progressing from hydric to mesic conditions.
p.5
Energy Flow in Ecosystems
Who are the primary consumers?
Herbivores that feed on producers.
p.2
Ecosystem Productivity: GPP and NPP
What is primary production?
The amount of energy produced by autotrophs in an ecosystem.
p.11
Ecological Succession: Primary and Secondary
How does primary succession in water progress?
From small phytoplanktons to rooted-submerged plants, rooted-floating angiosperms, and eventually to trees.
p.14
Nutrient Cycling: Gaseous and Sedimentary Cycles
How do plants obtain phosphorus?
Through the dissolution of phosphates in soil solution from weathered rocks.
p.17
Ecosystem Productivity: GPP and NPP
What is primary productivity?
The rate at which energy is converted by photosynthetic and chemosynthetic autotrophs to organic substances.
p.16
Ecological Succession: Primary and Secondary
What is ecological succession?
The sequential order of changes in a biotic community over time.
p.17
Nutrient Cycling: Gaseous and Sedimentary Cycles
What are the important features of a sedimentary cycle in an ecosystem?
Involves the cycling of nutrients through biological, geological, and chemical processes.
p.4
Decomposition Processes and Importance
What climatic factors are most important in regulating decomposition?
Temperature and soil moisture.
p.7
Energy Flow in Ecosystems
What are the typical levels in a grazing food chain?
Producer, herbivore, primary carnivore, secondary carnivore.
p.1
Definition and Structure of Ecosystems
What is the significance of studying the structure of ecosystems?
To understand input (productivity), transfer of energy, and output (degradation and energy loss).
p.2
Definition and Structure of Ecosystems
Who are the consumers in a pond ecosystem?
Zooplankton and free swimming or bottom dwelling forms.
p.5
Energy Flow in Ecosystems
What are the major producers in a terrestrial ecosystem?
Herbaceous and woody plants.
p.10
Interactions Between Biotic and Abiotic Components
What role do saprophytes play in ecosystems?
They play a vital role but are not represented in ecological pyramids.
p.16
Ecosystem Productivity: GPP and NPP
What is secondary productivity?
The rate of assimilation of food energy by consumers.
p.11
Ecological Succession: Primary and Secondary
What factors affect the species that invade during secondary succession?
Soil condition, water availability, environment, and presence of seeds or propagules.
p.3
Decomposition Processes and Importance
What is the role of detritivores in decomposition?
They break down detritus into smaller particles through fragmentation.
p.16
Energy Flow in Ecosystems
How does energy flow in ecosystems?
Energy flow is unidirectional, starting from plants capturing solar energy to food being transferred to decomposers.
p.14
Nutrient Cycling: Gaseous and Sedimentary Cycles
Is there a respiratory release of phosphorus into the atmosphere?
No, unlike the carbon cycle.
p.6
Energy Flow in Ecosystems
How does energy flow through the detritus food chain in terrestrial ecosystems compared to aquatic ones?
A much larger fraction of energy flows through the DFC in terrestrial ecosystems.
p.4
Decomposition Processes and Importance
What factors control the rate of decomposition?
Chemical composition of detritus and climatic factors.
p.1
Definition and Structure of Ecosystems
What is an ecosystem?
A functional unit of nature where living organisms interact among themselves and with the physical environment.
p.5
Energy Flow in Ecosystems
What is the primary source of energy for ecosystems on Earth?
The Sun, except for the deep sea hydro-thermal ecosystem.
p.1
Types of Ecosystems: Terrestrial and Aquatic
What are some examples of aquatic ecosystems?
Pond, lake, wetland, river, and estuary.
p.14
Nutrient Cycling: Gaseous and Sedimentary Cycles
Where is the majority of global carbon found?
71 percent is found dissolved in oceans.
p.1
Types of Ecosystems: Terrestrial and Aquatic
What are man-made ecosystems?
Ecosystems such as crop fields and aquariums.
p.11
Ecological Succession: Primary and Secondary
What are pioneer species?
Species that invade a bare area, such as lichens in primary succession on rocks.
p.17
Nutrient Cycling: Gaseous and Sedimentary Cycles
What is the major reservoir of carbon on Earth?
The atmosphere and oceans.
p.10
Ecological Succession: Primary and Secondary
What is secondary succession?
Succession that occurs in areas that have lost all living organisms.
p.9
Energy Flow in Ecosystems
What does each bar in the energy pyramid indicate?
The amount of energy present at each trophic level over a given time or annually per unit area.
p.2
Energy Flow in Ecosystems
What is the movement of energy in ecosystems?
Unidirectional movement towards higher trophic levels with loss as heat.
p.15
Ecosystem Services and Their Economic Value
What are some examples of ecosystem services provided by healthy forest ecosystems?
Purifying air and water, mitigating droughts and floods, cycling nutrients, generating fertile soils, and maintaining biodiversity.
p.5
Energy Flow in Ecosystems
What is the beginning of the detritus food chain/web?
The death of an organism.
p.6
Decomposition Processes and Importance
What types of organisms are primarily involved in the DFC?
Decomposers, mainly fungi and bacteria.
p.11
Ecological Succession: Primary and Secondary
How does the environment influence ecological succession?
Natural or human-induced disturbances can revert succession to an earlier stage and create new conditions for species.
p.17
Definition and Structure of Ecosystems
What are the components of an ecosystem?
Producers, consumers, decomposers, and abiotic factors.
p.3
Decomposition Processes and Importance
What are the important steps in the decomposition process?
Fragmentation, leaching, catabolism, humification, and mineralisation.
p.3
Decomposition Processes and Importance
What is humification?
A process during decomposition that leads to the formation of humus.
p.17
Ecological Pyramids: Number, Biomass, and Energy
What are ecological pyramids?
Graphical representations showing the distribution of biomass, numbers, or energy among trophic levels.
p.15
Ecosystem Services and Their Economic Value
Why is the value of biodiversity considered difficult to determine?
Because ecosystem services are largely taken for granted as they are free.
p.15
Nutrient Cycling: Gaseous and Sedimentary Cycles
What is the relationship between phosphorus cycling and ecosystems?
Phosphorus exchanges between organisms and the environment are negligible in ecosystems.
p.6
Ecological Pyramids: Number, Biomass, and Energy
What is a trophic level?
A specific place in the food chain based on the source of nutrition.
