Lesson Notes By Weeks and Term - Senior Secondary 2

TERM – 1^ST TERM

WEEK EIGHT

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Biology

Topic: NUTRIENTS CYCLING IN NATURE

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

1. Define nutrients cycling
2. Describe nutrients cycling using either carbon, oxygen or water cycle.

iii. Identify the importance of nutrient cycling in plant, animals and Man

1. Discuss carbon oxygen balance.

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 IN NATURE

Nutrient cycling in nature refers to the continuous movement and recycling of essential elements such as carbon, nitrogen, phosphorus, and others through various biotic and abiotic components of ecosystems. This process involves the uptake, transformation, and release of nutrients by living organisms and physical processes, contributing to the sustainability of ecosystems and supporting life forms at different trophic levels.

Carbon cycle

The carbon cycle is a natural process that describes the movement of carbon through the Earth's atmosphere, oceans, soil, and living organisms. It involves various interconnected processes that continuously exchange carbon between different reservoirs. The processes involved are as follows.

1. Photosynthesis: Plants, algae, and some bacteria use sunlight to convert carbon dioxide (CO2) from the atmosphere into organic compounds, releasing oxygen as a byproduct.
2. Respiration: Both plants and animals engage in respiration, releasing CO2 back into the atmosphere as they metabolize organic compounds to obtain energy.
3. Decomposition: Decomposers like bacteria and fungi break down dead organic matter, returning carbon to the soil in the form of organic compounds and releasing CO2.
4. Combustion: When organic matter, such as fossil fuels or biomass, is burned, carbon is released into the atmosphere as CO2. Human activities, like the burning of fossil fuels, significantly contribute to this process.
5. Ocean Uptake: Oceans absorb CO2 from the atmosphere through dissolution, and marine organisms incorporate carbon into their shells and tissues. This is known as the oceanic sink.

Oxygen cycle

The oxygen cycle is the biogeochemical cycle that describes the movement of oxygen within the atmosphere, biosphere, and lithosphere. It involves several processes:

1. Photosynthesis: Plants, algae, and certain bacteria use sunlight to convert carbon dioxide and water into glucose, releasing oxygen as a byproduct.
2. Respiration: Organisms, including plants, animals, and microorganisms, utilize oxygen for cellular respiration, breaking down organic compounds to produce energy and releasing carbon dioxide as a byproduct.
3. Decomposition: Decomposer organisms break down dead organic matter, releasing carbon dioxide and returning nutrients to the soil. This process can either be aerobic (using oxygen) or anaerobic (without oxygen).
4. Combustion: The burning of fossil fuels and biomass releases carbon dioxide and contributes to changes in atmospheric oxygen levels.

Water cycle

The water cycle, also known as the hydrological cycle, describes the continuous movement and exchange of water on, above, and below the Earth's surface. It involves several key processes:

1. Evaporation: Heat from the sun causes water from oceans, lakes, rivers, and other surface water bodies to turn into water vapor and rise into the atmosphere.
2. Condensation: As the water vapor rises, it cools and condenses into tiny water droplets, forming clouds in the atmosphere.
3. Precipitation: When cloud droplets combine and become heavy enough, precipitation (rain, snow, sleet, or hail) falls back to the Earth's surface.
4. Infiltration: Precipitation that falls on land can either be absorbed by the soil or surface runoff, moving across the land surface.
5. Transpiration: Plants absorb water from the soil through their roots and release water vapor into the atmosphere through tiny pores in their leaves.
6. Runoff: Excess water from precipitation, melting snow, or other sources that does not infiltrate the soil may flow over the surface, eventually reaching rivers, lakes, and oceans.

Importance of nutrients cycling to plants, animals and Man

Nutrient cycling is essential for the health and sustainability of ecosystems, providing vital elements for plants, animals, and humans. Here's a brief overview of the importance of nutrient cycling to these different components:

1. Plants:

I. Nutrients such as nitrogen, phosphorus, potassium, and others are crucial for plant growth, development, and reproduction.

II. Elements like carbon, hydrogen, and oxygen, obtained from nutrient cycling, are essential for photosynthesis, the process by which plants convert sunlight into energy.

2. Animals:

I. Animals obtain essential nutrients indirectly through the food they consume, which is derived from plants or other animals. Nutrient cycling ensures a continuous supply of these essential elements for animal growth and metabolism.

II. Animals contribute to nutrient cycling through processes like excretion and decomposition. The return of nutrients to the environment supports plant growth, closing the nutrient cycle.

3. Humans (Man):

I. Nutrient cycling is fundamental to agriculture as it ensures that crops receive the necessary nutrients for optimal growth. Humans, in turn, obtain these nutrients from plants and animals for their nutrition.

II. Essential nutrients like vitamins and minerals obtained through nutrient cycling are crucial for human health, supporting various bodily functions and preventing nutrient deficiencies.

Carbon-oxygen cycle

The carbon-oxygen balance refers to the equilibrium between carbon and oxygen levels in a given system, often discussed in the context of environmental science and climate change. This balance is crucial for maintaining a stable atmosphere and supporting life on Earth. Factors such as deforestation, combustion of fossil fuels, and industrial processes can disrupt this balance, leading to environmental issues like increased greenhouse gas concentrations and climate change. Maintaining a sustainable carbon-oxygen balance is essential for a healthy planet.

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