Ecosystems and Trophic Levels

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Questions and Answers

Which biome is characterized by being the richest ecosystems on earth?

Grassland

Desert

Savanna

Tropical rain forest (correct)

What percentage of the sun's energy is typically fixed by plants?

10%

0.1%

1% (correct)

20%

How much energy from a primary producer is available to a secondary consumer?

10% (correct)

0.1%

100%

What type of vegetation is primarily found in deserts?

Sparse vegetation Signup and view all the answers

Which biome serves as a transitional zone between tropical rain forests and deserts?

Savanna Signup and view all the answers

What limits the number of top-level carnivores in a community?

The loss of energy at each trophic level Signup and view all the answers

Which of the following components is NOT a part of biogeochemical cycling?

Energy Signup and view all the answers

What is the primary reason that most original grasslands have been transformed?

Agricultural use Signup and view all the answers

Which process is part of the organismic water cycle?

Transpiration from plants Signup and view all the answers

How many major and minor biomes are distributed throughout the earth?

Seven major and seven minor Signup and view all the answers

Which characteristic is common across all biomes?

Distinct climate and organisms Signup and view all the answers

What determines the amount of energy available to tertiary consumers?

Energy captured by photosynthesis Signup and view all the answers

Which statement accurately describes the role of water in ecosystems?

Water is reused and cycled in different forms. Signup and view all the answers

What adaptation might animals in a desert biome exhibit?

Water storage in tissues Signup and view all the answers

Where do biomes that occur at high latitudes typically also follow?

Altitudinal gradients along mountains Signup and view all the answers

Which trophic level generally supports fewer individuals?

Top-level carnivores Signup and view all the answers

How does deforestation impact the water cycle?

It prevents water from returning to the atmosphere. Signup and view all the answers

What is the primary source of local rainfall in dense forest ecosystems?

Transpiration from plants Signup and view all the answers

What percentage of freshwater in the United States exists as groundwater?

More than 96% Signup and view all the answers

Which process releases carbon into the atmosphere by burning biomass or fossil fuels?

Combustion Signup and view all the answers

How is carbon returned to the atmosphere from living organisms?

From respiration as a by-product Signup and view all the answers

What occurs to carbon during the process of erosion related to marine organisms?

It is released back to the oceans. Signup and view all the answers

What environmental concern arises from the increasing use of groundwater?

Chemical pollution Signup and view all the answers

What role does photosynthesis play in the carbon cycle?

It traps carbon in organic molecules. Signup and view all the answers

What defines the term 'habitat' in the context of ecosystems?

The place where a community lives Signup and view all the answers

Which statement is true regarding ecosystems?

Energy is captured and used by organisms within ecosystems. Signup and view all the answers

What is the role of producers in an ecosystem?

They capture energy through photosynthesis. Signup and view all the answers

What characterizes a consumer in an ecosystem?

They derive energy by consuming other organisms. Signup and view all the answers

How are organisms assigned to trophic levels?

By the number of consumption steps from the sun. Signup and view all the answers

What is a food chain?

A linear progression of energy transfer between trophic levels. Signup and view all the answers

Which organisms are considered the primary consumers in an ecosystem?

Herbivores that eat producers. Signup and view all the answers

What is the highest trophic level composed of in an ecosystem?

Secondary consumers Signup and view all the answers

What characteristic defines deciduous forests?

They drop their leaves in the winter. Signup and view all the answers

Which of the following best describes the taiga?

An area primarily consisting of coniferous trees. Signup and view all the answers

What is a notable feature of tundra ecosystems?

It usually contains permafrost near the surface. Signup and view all the answers

What environment is chaparral most closely associated with?

Dry, Mediterranean climates. Signup and view all the answers

Which statement is true about polar ice caps?

They are characterized by scarce freshwater and low precipitation. Signup and view all the answers

Which feature is commonly found in the taiga?

Predominantly coniferous trees. Signup and view all the answers

What is the primary climate characteristic of chaparral regions?

Dry summers with mild, wet winters. Signup and view all the answers

Which of the following best describes the vegetation in tundra regions?

Sparse vegetation due to harsh conditions. Signup and view all the answers

What is the primary process by which nitrogen becomes usable by living organisms?

Nitrogen fixation Signup and view all the answers

Where does nitrogen fixation primarily occur?

In oxygen-free environments Signup and view all the answers

What is the consequence of phosphorus pollution in aquatic ecosystems?

Eutrophication Signup and view all the answers

What accounts for up to 30% of the nitrogen cycle?

Industrial fixation of nitrogen Signup and view all the answers

In what form is phosphorus primarily found in ecosystems?

In soil or rock Signup and view all the answers

What happens to the oxygen levels in a lake during the eutrophication process?

Oxygen levels decrease as bacteria decompose algae Signup and view all the answers

Which of the following statements about the tropics is accurate?

They receive sunlight at nearly perpendicular angles Signup and view all the answers

What role do nitrogen-fixing bacteria play in agriculture?

They enhance the availability of fixed nitrogen Signup and view all the answers

Study Notes

Ecosystems

A community is a collection of organisms living in a specific place.
A habitat is the place where a community lives.
An ecosystem is the combination of a community and its habitat.
Ecosystems are the most complex level of biological organization.
Earth is a closed system for chemicals but an open system for energy.
Organisms in ecosystems regulate energy capture and expenditure, and the cycling of chemicals.
Producers capture energy, specifically autotrophs like plants, algae, and some bacteria.
Consumers obtain energy by consuming other organisms (heterotrophs).

Trophic Levels

Ecologists assign organisms to trophic levels, a feeding level.
Trophic levels represent the number of consumption steps away from the sun as a source of energy.
Food energy flows through ecosystems from one trophic level to another.
A food chain represents a simple linear sequence of consumption.
Decomposers break down dead organisms, finishing the food chain.

Ecological Pyramids

There are generally more individuals at lower trophic levels than higher ones.
Plants convert roughly 1% of the sun's energy into their parts.
Consumers process about 10% of the available energy from the organisms they consume.
Biomass (total weight of organisms) is typically higher at lower trophic levels.

The Water Cycle

Water is a vital nonliving ecosystem component influencing living things.
Water cycles within ecosystems through two main processes.
- The environmental water cycle involves water vapor condensing and falling as precipitation. Evaporation from water bodies reenters the atmosphere from lakes, rivers, and oceans.
- The organismic water cycle involves water being absorbed by plant roots and released into the atmosphere as transpiration from plant leaves.
Deforestation disrupts the water cycle in regions like tropical rainforests, where vegetation is a significant source of rainfall via transpiration.

The Carbon Cycle

Earth's atmosphere contains plentiful carbon dioxide.
Carbon cycles between the atmosphere and living organisms.
Plants capture carbon in organic molecules through photosynthesis.
Carbon returns to the atmosphere through respiration, combustion, and erosion.
Some carbon is stored as fossils for long periods. Burning fossil fuels releases this stored carbon.
Respiration, combustion, and erosion processes release carbon back to the atmosphere, soil, and oceans.

The Nitrogen & Phosphorus Cycles

Most organisms cannot use atmospheric nitrogen gas (N₂).
Specialized nitrogen-fixing bacteria convert atmospheric nitrogen into ammonia.
Nitrogen fixation occurs in the absence of oxygen.
Farmers often supplement fields with nitrogen fertilizers.
Industrial nitrogen fixation is a substantial part of the nitrogen cycle.
Phosphorus is essential for organisms because it is crucial for ATP and DNA.
Phosphorus is primarily found in soil or rock and is absorbed by plants.
Phosphorus is recycled back to the soil through the decomposition of organisms.

Latitude and Elevation

Temperature varies with elevation and latitude.
Air temperature falls about 6°C for every 1,000 meters increase in elevation, at any given latitude.
Rain shadows are areas on the leeward side of mountains where air loses moisture due to adiabatic cooling and rising. Precipitation is significantly reduced on the leeward side.

Ocean Ecosystems

Oceans are large, deep, cold, and mostly dark environments.
Photosynthesis in oceans is limited to shallow waters due to light penetration.
Organism below the surface level feed on organic material that descends from above.
Ocean ecosystems include shallow waters, open-sea surface, and deep-sea waters.
- Shallow waters are rich in species and include intertidal zones and estuaries;
- Open-sea surface has abundant phytoplankton performing photosynthesis;
- Deep-sea water support diverse, specialized life forms including some that are autotrophic and derive energy from hydrothermal vents.

Freshwater Ecosystems

Freshwater ecosystems, such as lakes, ponds, rivers, and wetlands.
Freshwater habitats are often connected to land habitats.
These ecosystems have distinctive zones like littoral, limnetic, and profundal.
Lakes can be classified as oligotrophic (low nutrients) and eutrophic (high nutrients), with corresponding differences in organic material and oxygen levels.
Thermal stratification and overturns are processes that occur in temperate regions, where stratified conditions are most significant in the spring and fall/winter.

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Description

This quiz explores the fundamental concepts of ecosystems and trophic levels, detailing how communities, habitats, and energy flow interact. Understand the roles of producers, consumers, and decomposers in maintaining ecological balance. Test your knowledge of biological organization and energy regulation within various ecosystems.