HS-LS2-5. Develop a model to illustrate the role of various processes in the cycling of carbon among the biosphere, atmosphere, hydrosphere, and geosphere.

Carbon is a fundamental element found in all living organisms, and it continuously cycles through Earth's systems, including the biosphere, atmosphere, hydrosphere, and geosphere. This cycling of carbon is vital for maintaining life on Earth and balancing global ecosystems. In this review, we will explore the main processes involved in the carbon cycle, such as photosynthesis, respiration, decomposition, and combustion. We will also discuss how models help illustrate the movement of carbon through different parts of the Earth.

Main Concepts

The Carbon Cycle: The carbon cycle is the process by which carbon moves between the Earth's biosphere (living organisms), atmosphere (air), hydrosphere (water bodies), and geosphere (land and rocks). This cycle ensures that carbon is available to living organisms while also being stored in various forms in the Earth’s systems.

Photosynthesis: Photosynthesis is the process by which plants, algae, and some bacteria take in carbon dioxide (CO₂) from the atmosphere and use sunlight to convert it into glucose, a form of stored energy. Oxygen is released as a byproduct. This process helps remove CO₂ from the atmosphere and stores carbon in the biosphere.

Respiration: Respiration is the process by which living organisms, including plants and animals, break down glucose to release energy. During respiration, carbon dioxide is released back into the atmosphere, contributing to the carbon cycle.

Decomposition: When plants and animals die, decomposers like bacteria and fungi break down their organic matter. This process releases carbon back into the atmosphere as carbon dioxide or into the soil, where it can be stored for long periods.

Combustion: Combustion, or burning, is a process that occurs when organic materials, such as fossil fuels or wood, are burned. This releases stored carbon back into the atmosphere as carbon dioxide, contributing to the carbon cycle.

Modeling the Carbon Cycle: Models, such as simulations, diagrams, and mathematical representations, help illustrate how carbon moves through different Earth systems. These models show the interactions between processes like photosynthesis, respiration, decomposition, and combustion, and how they contribute to the overall carbon cycle.

Review Questions and Answers

1. What is the carbon cycle?

The carbon cycle is the process by which carbon moves between the biosphere, atmosphere, hydrosphere, and geosphere, ensuring that carbon is available to living organisms and stored in various Earth systems.

2. How does photosynthesis contribute to the carbon cycle?

Photosynthesis removes carbon dioxide from the atmosphere and converts it into glucose, storing carbon in the biosphere and releasing oxygen as a byproduct.

3. What happens during respiration in the carbon cycle?

During respiration, living organisms break down glucose to release energy, and carbon dioxide is released back into the atmosphere.

4. What role do decomposers play in the carbon cycle?

Decomposers break down dead plants and animals, releasing carbon back into the atmosphere as carbon dioxide or into the soil, where it can be stored.

5. How does combustion affect the carbon cycle?

Combustion releases stored carbon from organic materials, such as fossil fuels, back into the atmosphere as carbon dioxide, contributing to the carbon cycle.

6. What are the four main Earth systems involved in the carbon cycle?

The four main Earth systems involved in the carbon cycle are the biosphere, atmosphere, hydrosphere, and geosphere.

7. Why is carbon important for life on Earth?

Carbon is a fundamental element in all living organisms and is essential for building the molecules that make up cells and tissues.

8. What is the significance of modeling the carbon cycle?

Modeling the carbon cycle helps us understand how carbon moves through Earth’s systems and the impact of human activities on this cycle.

9. How do human activities, such as burning fossil fuels, impact the carbon cycle?

Human activities, such as burning fossil fuels, increase the amount of carbon dioxide in the atmosphere, which can lead to climate change and affect the balance of the carbon cycle.

10. What is the relationship between the carbon cycle and climate change?

The carbon cycle plays a key role in regulating the Earth’s climate. An increase in carbon dioxide in the atmosphere, due to human activities, can contribute to global warming and climate change.

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Disclaimer: The information provided is intended to serve as a study guide based on a contextual analysis of the NGSS standards for the Life Science Biology assessment. These study guides should be used as a supplement to your overall study strategy, and their alignment to the actual test format is not guaranteed. We recommend that you consult with your instructor for additional guidance on exam preparation.