Ecosystem Structure and Function Quiz

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Questions and Answers

What are the two main categories of ecosystems?

Terrestrial and Aquatic

What do you call the vertical distribution of different species occupying different levels in an ecosystem?

Stratification

The breakdown of complex organic matter into inorganic substances like carbon dioxide, water and nutrients is called ______.

decomposition

What is defined as the rate of formation of new organic matter by consumers?

Secondary Productivity Signup and view all the answers

Primary productivity depends solely on the availability of sunlight.

False Signup and view all the answers

The amount of energy in an ecosystem always increases as you move up through the trophic levels.

False Signup and view all the answers

Which type of pyramid typically shows an inverted shape due to the large biomass of phytoplankton supporting a smaller biomass of zooplankton?

Pyramid of Biomass Signup and view all the answers

What is the name of the dark-colored amorphous substance formed during humus accumulation?

Humus Signup and view all the answers

What is the process by which producers convert light energy into chemical energy in the form of organic matter?

Photosynthesis Signup and view all the answers

In the context of ecosystems, what is the significance of decomposers?

They break down dead organic matter, releasing nutrients back into the ecosystem for reuse by producers. Signup and view all the answers

What is the main conduit for energy flow in aquatic ecosystems?

Grazing Food Chain (GFC) Signup and view all the answers

What is the definition of standing crop?

The amount of living material present at a particular time in a unit area. Signup and view all the answers

The transfer of energy between trophic levels always follows the 10% rule, meaning that 10% of the energy is transferred to the next trophic level.

False Signup and view all the answers

What are ecological pyramids?

Graphical representations that show the relative number, biomass, or energy at different trophic levels in an ecosystem. Signup and view all the answers

Name three limitations of ecological pyramids.

They don't account for food webs, the same species can occupy multiple trophic levels, and saprophytes are often excluded. Signup and view all the answers

Study Notes

Ecosystem Structure and Function

An ecosystem is a functional unit of nature, encompassing living organisms interacting with their physical environment.
Ecosystems vary greatly in size, from small ponds to large forests or seas.
The biosphere is considered a global ecosystem, a composite of all local ecosystems.
Studying entire ecosystems is complex, thus they are classified into terrestrial and aquatic categories (e.g., forests, grasslands, deserts; ponds, lakes, wetlands).
Man-made ecosystems include crop fields and aquariums.

Ecosystem Components

Ecosystem components include abiotic (non-living: air, water, soil) and biotic (living: producers, consumers, decomposers).
Producers (plants and photosynthetic bacteria) capture solar energy to produce organic matter.
Consumers (herbivores and carnivores) obtain energy by consuming producers or other consumers.
Decomposers (fungi and bacteria) break down dead organisms and waste materials into inorganic substances.

Productivity

Primary productivity is the rate of biomass production by producers during photosynthesis.
Gross primary productivity (GPP) is the total rate of primary production.
Net primary productivity (NPP) is GPP minus the energy used by producers in respiration.
Secondary productivity is the rate at which consumers produce new organic matter.

Decomposition

Decomposition is the breakdown of complex organic matter into simpler inorganic substances (carbon dioxide, water, nutrients).
Detritivores (e.g., earthworms) fragment detritus.
Nutrient leaching.
Catabolism (decomposing detritus into simpler compounds) occurs by bacteria and fungi.
Humification builds up the dark, colloidal humus.
Mineralisation releases inorganic nutrients back into the ecosystem.
Decomposition rates vary based on detritus composition and environmental factors (temperature, moisture).

Energy Flow

The sun is the primary energy source for most ecosystems.
Photosynthetic organisms capture a small portion of solar energy for food production.
Energy flows unidirectionally through ecosystems, from producers through various trophic levels (producers, primary consumers, secondary consumers, tertiary consumers).
Energy is lost as heat at each trophic level.
The detritus food chain begins with dead organic matter, and decomposers are responsible for breaking it down.

Ecological Pyramids

Ecological pyramids depict the relationship between trophic levels.
Pyramids of numbers, biomass, and energy are used to represent the structure of an ecosystem.
Pyramids of numbers show the number of organisms at each level; pyramids of biomass depict the total mass of organisms at each level; pyramids of energy show the energy flow.
Ecological pyramids are generally upright in most ecosystems, but they can be inverted in certain situations, such as aquatic ecosystems where the biomass of producers is smaller than that of secondary consumers.

Important Concepts

Standing crop: The total mass of living organisms at a particular trophic level at a given time.
Ecosystem Services: Processes that occur in an ecosystem, for example, purification of air and water by forests.

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Description

Test your knowledge on the structure and function of ecosystems. This quiz covers the components of ecosystems, including abiotic and biotic factors, as well as the classification of ecosystems into terrestrial and aquatic categories. Explore the relationships between producers, consumers, and decomposers within various ecosystems.