Cycling Through Life: Biogeochemical Cycles in Ecosystems

Biology Grades High School 7:54 Video
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Lesson Description

Explore the essential biogeochemical cycles that sustain life on Earth. This lesson examines the water, carbon, nitrogen, and phosphorus cycles, emphasizing their importance in ecosystems and the biosphere.

Video Resource

Biogeochemical cycles | Ecology | Khan Academy

Khan Academy

Duration: 7:54
Watch on YouTube

Key Concepts

  • Biogeochemical Cycles: Processes where essential elements are recycled through ecosystems.
  • Water Cycle: The continuous movement of water on, above, and below the surface of the Earth.
  • Carbon Cycle: The process by which carbon atoms continually travel from the atmosphere to the Earth and then back into the atmosphere.
  • Nitrogen Cycle: The series of processes by which nitrogen and its compounds are interconverted in the environment and in living organisms, including nitrogen fixation and decomposition.
  • Phosphorus Cycle: The biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere.

Learning Objectives

  • Define biogeochemical cycles and explain their importance in sustaining life.
  • Describe the key processes involved in the water, carbon, nitrogen, and phosphorus cycles.
  • Explain the role of living organisms in biogeochemical cycles.
  • Analyze the impact of human activities on biogeochemical cycles.

Educator Instructions

  • Introduction (5 mins)
    Begin by asking students what they already know about recycling. Then, introduce the concept of biogeochemical cycles as nature's recycling system for essential elements.
  • Video Viewing (10 mins)
    Play the Khan Academy video 'Biogeochemical cycles | Ecology | Khan Academy'. Instruct students to take notes on the key cycles discussed (water, carbon, nitrogen, and phosphorus).
  • Cycle Breakdown (20 mins)
    Divide students into four groups, assigning each group one of the following cycles: water, carbon, nitrogen, or phosphorus. Have each group create a diagram or flowchart illustrating the key processes and components of their assigned cycle. Students will present their cycle and explain it's importance.
  • Discussion (10 mins)
    Facilitate a class discussion about the interconnectedness of the biogeochemical cycles and the potential consequences of disrupting these cycles.
  • Wrap-up and Assessment (5 mins)
    Administer a short multiple-choice or fill-in-the-blank quiz to assess student understanding.

Interactive Exercises

  • Cycle Diagram Creation
    Students create visual diagrams of the water, carbon, nitrogen, or phosphorus cycle, labeling key processes and reservoirs. These diagrams could be created digitally or on paper.
  • Role-Playing: Element's Journey
    Students role-play as a molecule of water, carbon, nitrogen, or phosphorus, tracing their journey through the various stages of their respective cycle.

Discussion Questions

  • How are the different biogeochemical cycles interconnected?
  • What are some human activities that can disrupt biogeochemical cycles?
  • What are the potential consequences of disrupting biogeochemical cycles?
  • How can we minimize our impact on biogeochemical cycles?

Skills Developed

  • Critical Thinking
  • Scientific Communication
  • Data Interpretation
  • Systems Thinking

Multiple Choice Questions

Question 1:

Which of the following is NOT a major biogeochemical cycle?

Correct Answer: Sodium cycle

Question 2:

What is the primary role of photosynthesis in the carbon cycle?

Correct Answer: Removing carbon dioxide from the atmosphere

Question 3:

Which process converts atmospheric nitrogen into a usable form for plants?

Correct Answer: Nitrogen fixation

Question 4:

In the water cycle, what is the process by which water changes from a liquid to a gas?

Correct Answer: Evaporation

Question 5:

Which of the following biomolecules contains phosphorus?

Correct Answer: Nucleic acids

Question 6:

Which of the following processes releases carbon back into the atmosphere?

Correct Answer: Respiration

Question 7:

What is the role of decomposers in biogeochemical cycles?

Correct Answer: To break down organic matter

Question 8:

Which gas makes up most of the atmosphere?

Correct Answer: Nitrogen

Question 9:

What is ATP?

Correct Answer: Adenosine Triphosphate

Question 10:

What type of organism completes photosynthesis?

Correct Answer: Autotroph

Fill in the Blank Questions

Question 1:

The continuous movement of water on, above, and below the surface of the Earth is called the _________ cycle.

Correct Answer: water

Question 2:

_________ is the process where plants use light energy to convert carbon dioxide and water into glucose.

Correct Answer: photosynthesis

Question 3:

The conversion of atmospheric nitrogen into ammonia, a form usable by plants, is called nitrogen _________.

Correct Answer: fixation

Question 4:

Decomposers release carbon back into the environment through the process of _________.

Correct Answer: decomposition

Question 5:

_________ is a molecule that contains phosphorus and is essential for energy transfer in cells.

Correct Answer: ATP

Question 6:

Carbon in the atmosphere is primarly in the form of _________.

Correct Answer: carbon dioxide

Question 7:

Nitrogen is a key component of _________ bases, which make up DNA.

Correct Answer: nitrogenous

Question 8:

Animals obtain nitrogen by consuming _________ or other animals that have consumed them.

Correct Answer: plants

Question 9:

The process by which water vapor cools and changes into liquid form is known as _________

Correct Answer: condensation

Question 10:

A _________ is an organism that can produce its own food from light, water, carbon dioxide, or other chemicals.

Correct Answer: autotroph

Educational Standards

B.LS2.3:Construct and revise an explanation based on evidence for the cycling of matter and the flow of energy in aerobic and anaerobic conditions. B.LS2.5:Develop a model to illustrate the role of photosynthesis and cellular respiration in the cycling of carbon among the biosphere, atmosphere, hydrosphere, and geosphere. B.LS1.6:Construct and revise an explanation based on evidence for how carbon, hydrogen, and oxygen from sugar molecules may combine with other elements to form amino acids and/or other large carbon-based molecules.

Teaching Materials

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