Lesson Notes By Weeks and Term - Senior Secondary 1

TERM – 1^ST TERM

WEEK TEN

Class: Senior Secondary School 1

Age: 15 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Biology

Topic: NUTRIENT CYCLING IN NATURE

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

1. Explains nutrient cycling
2. Discuss the processes of nutrient cycling
3. Draw and describe carbon cycle
4. Draw and describe oxygen cycle
5. Explain how carbon and oxygen are balanced in nature

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

NOTE

NUTRIENT CYCLING

Nutrient cycling carbon and oxygen

Nutrient cycling, also known as biogeochemical cycling, refers to the movement and exchange of essential nutrients and elements through various components of an ecosystem. These elements, including carbon, nitrogen, phosphorus, sulfur, and others, are essential for the growth and development of living organisms.

The nutrient cycling process involves several stages:

1. Uptake: Nutrients are taken up by plants from the soil or water. In aquatic ecosystems, phytoplankton play a crucial role in nutrient uptake.
2. Consumption: Herbivores and other organisms consume plants, incorporating nutrients into their tissues. This continues up the food chain as predators consume herbivores.
3. Decomposition: When organisms die, decomposers like bacteria and fungi break down their organic matter. This decomposition releases nutrients back into the soil or water.
4. Mineralization: Decomposition converts organic matter into inorganic forms, making nutrients available for plants to uptake once again.
5. Leaching: Nutrients can be lost from the system through leaching, where water carries dissolved nutrients away from the soil or vegetation.
6. Runoff: Nutrients can also be transported via runoff, especially in terrestrial ecosystems, affecting water quality in rivers and oceans.
7. Human Impact: Human activities, such as deforestation, agriculture, and industrial processes, can disrupt nutrient cycles, leading to imbalances and environmental issues.

Carbon cycle

The carbon cycle is a natural process that describes the movement of carbon among the Earth's atmosphere, oceans, soil, rocks, and living organisms. It is a vital component of Earth's biogeochemical systems and plays a crucial role in regulating the planet's climate.

Oxygen cycle

The oxygen cycle is the continuous movement of oxygen through Earth's various spheres—atmosphere, lithosphere (Earth's crust), and biosphere (living organisms).

Importance of Nutrient Cycling

The following are the importance of nutrients cycling in nature:

1. Sustaining Ecosystem Health: Nutrient cycling is crucial for maintaining the health and functionality of ecosystems. It ensures a continuous supply of essential elements necessary for the growth and development of plants and other organisms.
2. Supporting Plant Growth: Nutrients like nitrogen, phosphorus, and potassium are vital for plant growth. Nutrient cycling ensures that these elements are recycled in the ecosystem, providing a constant supply for plants.
3. Soil Fertility: Nutrient cycling contributes to soil fertility by recycling organic matter and releasing nutrients back into the soil. This enhances the soil's ability to support plant life and agricultural productivity.
4. Biodiversity: Healthy nutrient cycling supports diverse plant and animal communities. Different organisms play roles in nutrient cycling, contributing to the richness and diversity of ecosystems.
5. Water Quality: Nutrient cycling influences the quality of water in rivers, lakes, and oceans. Proper cycling helps prevent nutrient runoff, which can lead to water pollution and harmful algal blooms.
6. Waste Decomposition: Nutrient cycling involves the decomposition of organic matter by microorganisms. This process breaks down waste materials and recycles nutrients, preventing the accumulation of organic debris.
7. Energy Flow in Ecosystems: Nutrient cycling is integral to the flow of energy in ecosystems. It ensures that nutrients are transferred through the food web, supporting the growth and functioning of different trophic levels.

Carbon-oxygen balance

The carbon-oxygen balance refers to the equilibrium between the cycles of carbon and oxygen in the Earth's atmosphere and ecosystems. These two cycles are interconnected and play crucial roles in maintaining environmental stability and supporting life on the planet. The following are the important aspects of the carbon-oxygen balance:

1. Photosynthesis and Respiration: The carbon-oxygen balance is closely tied to the processes of photosynthesis and respiration. During photosynthesis, plants absorb carbon dioxide and release oxygen, contributing to oxygen production. In contrast, during respiration, organisms, including plants, consume oxygen and release carbon dioxide.
2. Carbon Sink and Source: Plants act as carbon sinks during photosynthesis, storing carbon in the form of carbohydrates. On the other hand, during respiration, both plants and animals become carbon sources as they release carbon dioxide back into the atmosphere.
3. Global Carbon Cycle: The balance is crucial on a global scale as the carbon cycle influences atmospheric carbon dioxide levels. Disruptions to this balance, such as increased carbon emissions from human activities like burning fossil fuels and deforestation, can contribute to climate change.
4. Human Impact: Human activities, particularly the burning of fossil fuels and deforestation, have disrupted the carbon-oxygen balance. Excessive carbon dioxide emissions contribute to the greenhouse effect, impacting global temperatures and weather patterns.
5. Ocean's Role: Oceans play a significant role in maintaining the carbon-oxygen balance. They absorb carbon dioxide from the atmosphere, helping regulate atmospheric levels. However, increased carbon dioxide absorption can lead to ocean acidification, affecting marine ecosystems.
6. Forests and Biodiversity: Forests contribute to the carbon-oxygen balance by acting as carbon sinks. Deforestation disrupts this balance, reducing the number of trees available for photosynthesis and contributing to increased carbon dioxide levels.

EVALUATION: 1. What is nutrient cycling

2. Discuss the carbon cycle
3. How is carbon and oxygen balanced in nature

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively