Lesson Notes By Weeks and Term - Senior Secondary 1

TERM – 2^ND TERM

WEEK SEVEN

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. Define and describe the process of carbon cycle
2. Define and describe the process of oxygen cycle
3. Define and describe the process of Nitrogen cycle
4. Define and describe the process of water cycle.
5. Describe tolerance.

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers,

demonstration, videos from source

INSTRUCTIONAL MATERIALS:  Videos, loud speaker, textbook, picture

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

NOTE

NUTRIENT CYCLING IN NATURE

Nutrient cycling in nature refers to the movement and exchange of essential elements, such as carbon, nitrogen, phosphorus, and other minerals, through various biological, geological, and chemical processes within ecosystems. These cycles involve the uptake, utilization, and recycling of nutrients by living organisms, contributing to the balance and sustainability of ecosystems.

Process of Nutrient Cycling in Nature

1. Decomposition: Dead organic matter is broken down by decomposers (bacteria, fungi), releasing nutrients into the soil.
2. Mineralization: Decomposers convert organic nutrients into inorganic forms (e.g., ammonium), making them available for plant uptake.
3. Nutrient Uptake by Plants: Plants absorb nutrients from the soil for growth and development.
4. Consumption and Trophic Levels: Organisms at higher trophic levels consume plants or other animals, incorporating nutrients into their bodies.
5. Excretion and Waste Decomposition: Animals excrete waste containing nutrients. Decomposers break down these wastes, releasing more nutrients.
6. Leaching and Runoff: Excess nutrients in the soil can be leached into groundwater or carried away by runoff, affecting nutrient availability.
7. Denitrification: Certain bacteria convert nitrates in the soil back into nitrogen gas, completing the nitrogen cycle.

Importance of Nutrient Cycling

1. Nutrient cycling sustains life by ensuring a continuous supply of essential elements for plant growth and ecosystem functioning.
2. Balanced nutrient cycles maintain ecosystem health, supporting diverse plant and animal communities.
3. Cycling replenishes soil nutrients, promoting fertility and enhancing agricultural productivity.
4. Proper nutrient cycling minimizes nutrient runoff, preserving water quality in rivers and lakes.
5. Nutrient cycles, especially the carbon cycle, play a role in regulating atmospheric carbon dioxide levels and influencing climate.
6. Nutrient availability contributes to diverse habitats, fostering biodiversity within ecosystems.
7. Nutrient cycling influences the availability of essential nutrients for food crops, impacting human nutrition.
8. Nutrient cycling is integral to the flow of energy through ecosystems, supporting food webs and ecological processes.

Carbon Cycle

The carbon cycle is a natural process that involves the movement of carbon through the Earth's atmosphere, oceans, soil, and living organisms. It is a crucial component of life on Earth and includes the following key processes:

1. Photosynthesis: Plants, algae, and some bacteria absorb carbon dioxide (CO2) from the atmosphere during photosynthesis, converting it into organic compounds like glucose.
2. Respiration: Organisms, including plants, animals, and microorganisms, release carbon dioxide back into the atmosphere through respiration as they break down organic compounds to obtain energy.
3. Decomposition: Dead plants and animals are broken down by decomposers (bacteria, fungi), releasing carbon back into the soil.
4. Combustion: The burning of fossil fuels (coal, oil, and natural gas) releases carbon dioxide into the atmosphere. This process is a significant contributor to the increased concentration of CO2.
5. Ocean Absorption: Oceans act as a large carbon sink, absorbing carbon dioxide from the atmosphere. This absorption is essential for regulating atmospheric CO2 levels.
6. Carbonate Formation: Marine organisms, such as coral and shellfish, extract carbon from the water to form calcium carbonate, which contributes to the carbon stored in ocean sediments.
7. Fossilization: Over geological time, organic matter can become fossil fuels like coal, oil, and natural gas, locking carbon away from the active carbon cycle.
8. Deforestation and Land-Use Changes: Human activities, such as deforestation and changes in land use, can impact the carbon cycle by altering the balance between carbon uptake and release.

The Nitrogen cycle

The nitrogen cycle is a natural process that transforms nitrogen through various forms in the environment. It involves nitrogen fixation by bacteria, nitrification, denitrification, and assimilation by plants. This cycle plays a crucial role in maintaining the balance of nitrogen in ecosystems, supporting plant growth and sustaining life.

The oxygen cycle

The oxygen cycle is a biogeochemical process that involves the movement of oxygen through different components of the Earth's ecosystem. It includes processes such as photosynthesis, respiration, and decomposition. Plants and algae produce oxygen during photosynthesis, which is then released into the atmosphere. Animals, including humans, utilize oxygen through respiration, releasing carbon dioxide. Decomposition of organic matter also plays a role in returning nutrients and oxygen to the environment. This cycle helps maintain the balance of oxygen in the atmosphere, crucial for supporting life.

The water cycle

The water cycle also known as the hydrologic cycle is a continuous process where water evaporates from the Earth's surface, forms clouds in the atmosphere, falls as precipitation, and eventually returns to bodies of water through runoff or infiltration, completing the cycle as described in the diagram below.

Tolerance

In the ecosystem, tolerance refers to the ability of species to endure or thrive in a range of environmental conditions. Biodiversity often depends on the tolerance of different species to various factors like temperature, humidity, and nutrient levels. This adaptability contributes to the stability and resilience of ecosystems.

EVALUATION: 1.What is nutrient cycling

2. Mention 5 importance of nutrients cycling
3. Discuss the carbon cycle
4. Define tolerance.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively