Ecology Trophic Levels and Cycles Quiz

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Questions and Answers

What does a food web illustrate in an ecosystem?

The complexity of the nitrogen cycle

How energy is created

Only one route of energy transfer

All possible feeding relationships at each trophic level (correct)

An ecological pyramid can represent how energy flows through an ecosystem.

True

What do autotrophs represent in the ecological pyramid?

The base or first trophic level

The process of cycling elements among living organisms and the abiotic environment is referred to as the ______ cycle.

biogeochemical Signup and view all the answers

Match the following trophic levels with their roles:

Autotrophs = Producers of energy Heterotrophs = Consumers of energy Decomposers = Break down dead material Herbivores = Primary consumers Signup and view all the answers

Which of the following statements best describes the second Law of Thermodynamics in the context of energy transfer?

Some energy is transformed into unusable heat during transfers. Signup and view all the answers

A food chain is more complex than a food web.

False Signup and view all the answers

Identify one role of decomposers in an ecosystem.

To break down dead organic material Signup and view all the answers

Which process in the water cycle follows evaporation?

Condensation Signup and view all the answers

Nitrogen-fixing bacteria convert nitrogen gas directly into proteins.

False Signup and view all the answers

What primarily characterizes the tundra ecosystem?

Treeless regions with harsh climatic conditions Signup and view all the answers

What role does carbon dioxide (CO2) play in the carbon cycle?

It is used by plants during photosynthesis to create organic molecules. Signup and view all the answers

Savannas have a forage component that is mainly from grasses that only grow during the wet season.

False Signup and view all the answers

Phosphorus moves through the food web and returns to the soil during __________.

decomposition Signup and view all the answers

What is the primary difference between steppes and savannas regarding forage availability?

Steppes provide forage only during the wet season, while savannas have forage from grasses that grow in both wet and dry seasons. Signup and view all the answers

Match the following biogeochemical cycles with their primary characteristics:

Nitrogen Cycle = Involves nitrogen-fixing bacteria Water Cycle = Circulates water through evaporation and precipitation Carbon Cycle = Transports carbon through photosynthesis and respiration Phosphorus Cycle = Relies on weathering of rocks for phosphate Signup and view all the answers

Which of the following is NOT a step in the water cycle?

Photosynthesis Signup and view all the answers

The primary nutrient that both mining and agriculture add to the environment is __________.

phosphorus Signup and view all the answers

Match the following types of ecosystems with their characteristics:

Tundra = Treeless regions with permafrost Freshwater = Includes lakes and rivers Oceanic marine = Saltwater environment of the continental shelf Grasslands = Dominated by grasses and few trees Signup and view all the answers

Carbon sinks are areas where carbon is stored for long periods of time.

True Signup and view all the answers

What are the primary gases involved in the nitrogen cycle?

Nitrogen gas (N2) and ammonia (NH3) Signup and view all the answers

Which of the following statements about the freshwater environment is correct?

It is subdivided into standing-water and running-water habitats. Signup and view all the answers

All ecosystems have similar amounts of nutrient availability.

False Signup and view all the answers

What is a defining characteristic of the oceanic marine environment?

It is characterized by saltwater and includes the shallow waters of the continental shelf. Signup and view all the answers

Study Notes

Trophic Levels and Ecological Concepts

Higher trophic levels are positioned above one another in an ecological hierarchy, forming a pyramid structure.
Each organism in a food chain represents a feeding step, or trophic level, indicating energy and material transfer.
A food chain illustrates a single route for matter and energy through an ecosystem, while a food web depicts multiple feeding relationships at each trophic level.

Cycles of Life

Water Cycle: The hydrologic cycle includes evaporation, condensation, transpiration, and precipitation, maintaining the circular movement of water on Earth.
Nitrogen Cycle: Essential for producing organic molecules like amino acids; nitrogen is mostly gaseous (N2) in the atmosphere. Nitrogen-fixing bacteria convert it into ammonia, either living in plant nodules or in soil.
Carbon Cycle: Carbon cycles through the atmosphere mainly as carbon dioxide (CO2), absorbed by green plants for photosynthesis to create glucose. Carbon can be stored in carbon sinks and is released back through fossil fuel combustion.
Phosphorus Cycle: Phosphates are released from rock weathering and cycle through the food web, returning to soil during decomposition, with some leaching into groundwater.

Energy Flow in Ecosystems

Energy flow is vital to ecological understanding; it adheres to the First Law of Thermodynamics (energy is transformed, not created or destroyed) and the Second Law (some energy is lost as heat during transfers).
An ecological food pyramid illustrates energy flow, with autotrophs forming the base, representing the first trophic level.

Ecosystem Types

Terrestrial Ecosystems: Land-based environments consisting of various biomes, including grasslands, forests, savannas, and deserts.
Tundra: A treeless, barren ecosystem with severe cold climates, characterized by short summers, scant snowfall, permafrost soil, and low nutrient availability.
Aquatic Ecosystems:
- Freshwater: Includes standing-water habitats like lakes and running-water habitats such as rivers.
- Oceanic Marine: Composed of saltwater, broadly divided into shallow continental shelf waters and deeper ocean zones.

Food Chain and Food Web

A food chain is a simplified model showing nutrient and energy flow from autotrophs to heterotrophs and eventually to decomposers.
Arrows in food chains indicate energy transfer direction, typically containing 3 to 5 trophic links. A food web offers a more complex view of energy interactions within a community.

Nutrient Cycling

In self-sustaining ecosystems, nutrients cycle between biotic (living) and abiotic (non-living) environments, forming a complex biogeochemical cycle essential for ecosystem health.

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Description

Test your knowledge on the ecology of trophic levels and the essential cycles of life, including the water and nitrogen cycles. This quiz covers the processes involved in these cycles and their significance in ecosystems. Perfect for students studying environmental science or ecology.