Nutrient Cycles, Food chains and Food Web Basic Science Jss 2 First Term Lesson Notes Week 4
Subject: Basic Science
Class: JSS 2
Term: First Term
Week: 4
Age: 12-13 years
Topic: Nutrient Cycles, Food Chains, and Food Webs
Sub-topic: Understanding Nutrient Cycles, Food Chains, and Food Webs
Duration: 60 minutes
Behavioral Objectives:
By the end of the lesson, students should be able to:
- Define nutrient cycles, food chains, and food webs.
- Describe the flow of energy through food chains and food webs.
- Identify the roles of producers, consumers, and decomposers in nutrient cycles and food webs.
- Draw and interpret diagrams of food chains and food webs.
Keywords:
- Nutrient Cycle
- Food Chain
- Food Web
- Producer
- Consumer
- Decomposer
Set Induction:
Begin the lesson with a short video or animation showing how energy flows through a food chain and food web in an ecosystem. Ask students to observe and discuss the roles of different organisms in the video.
Entry Behavior:
Students have basic knowledge of ecosystems and the roles of different organisms from previous lessons.
Learning Resources and Materials:
- Diagrams of food chains and food webs
- Models or pictures of animals and plants in a food web
- Textbooks
- Workbooks
- Online materials (e.g., educational websites or interactive simulations)
Building Background/Connection to Prior Knowledge:
Discuss how different organisms interact in an ecosystem and how energy is transferred from one organism to another. Link this to the concept of nutrient cycles.
Embedded Core Skills:
- Critical thinking
- Diagram interpretation
- Understanding ecological relationships
Learning Materials:
- Basic Science textbooks
- Science workbooks with exercises on food chains and webs
- Interactive online resources and simulations
Reference Books:
- Lagos State Scheme of Work
- Comprehensive Basic Science for Junior Secondary Schools
- Understanding Basic Science for JSS
Instructional Materials:
- Diagrams showing food chains and food webs
- Models or pictures of various animals and plants
- Visual aids to illustrate nutrient cycles
Content:
Nutrient Cycles:
- Definition and Importance:
- Nutrient cycles describe the movement of nutrients through the environment and living organisms.
- Key cycles include the carbon cycle, nitrogen cycle, and water cycle.
- Example: In the carbon cycle, plants take in carbon dioxide, and animals release carbon dioxide through respiration.
- Key Components:
- Producers: Organisms that produce their own food through photosynthesis (e.g., plants).
- Consumers: Organisms that consume other organisms for energy (e.g., animals).
- Decomposers: Organisms that break down dead plants and animals, returning nutrients to the soil (e.g., fungi, bacteria).
Food Chains:
- Definition and Structure:
- A food chain shows the direct flow of energy from one organism to another.
- Example: Grass → Grasshopper → Frog → Snake → Hawk.
- Each organism in the chain is a link in the chain of energy transfer.
- Roles of Organisms:
- Producers: Start the chain by converting sunlight into energy (e.g., plants).
- Primary Consumers: Herbivores that eat producers (e.g., grasshoppers).
- Secondary Consumers: Carnivores that eat herbivores (e.g., frogs).
- Tertiary Consumers: Top predators that eat other consumers (e.g., hawks).
Food Webs:
- Definition and Complexity:
- A food web is a complex network of interconnected food chains within an ecosystem.
- Example: In a grassland ecosystem, various plants and animals form a complex web of feeding relationships.
- Energy Flow:
- Food webs show how energy and nutrients are transferred between different organisms in an ecosystem.
- They illustrate the interdependence of species.
Evaluation Questions:
- What is a nutrient cycle and why is it important?
a) The movement of nutrients through living and non-living parts of an ecosystem
b) The flow of energy in a food chain
c) The process of photosynthesis
d) The interaction between predators and prey - Which of the following is an example of a food chain?
a) Grass → Grasshopper → Frog → Snake → Hawk
b) Grass → Bird → Snake → Hawk
c) Plants → Insects → Birds
d) Algae → Fish → Shark - What role do producers play in a food chain?
a) They provide energy to consumers
b) They break down dead organisms
c) They consume other organisms
d) They help regulate temperature - In a food web, which organisms are considered primary consumers?
a) Plants
b) Herbivores
c) Carnivores
d) Decomposers - What is the function of decomposers in nutrient cycles?
a) To produce energy
b) To consume plants
c) To break down dead matter and return nutrients to the soil
d) To compete for resources - How does energy flow through a food chain?
a) From producers to consumers to decomposers
b) From consumers to producers
c) From decomposers to consumers
d) From one consumer to another - What is a food web?
a) A single food chain
b) A complex network of interconnected food chains
c) A cycle of nutrients
d) A group of decomposers - In a food web, what does an arrow represent?
a) Energy transfer
b) A food source
c) A competition
d) A nutrient cycle - Which of the following is an example of a secondary consumer?
a) Grasshopper
b) Frog
c) Hawk
d) Plant - What is the main difference between a food chain and a food web?
a) A food chain shows direct energy transfer, while a food web shows multiple interconnected chains
b) A food web shows direct energy transfer, while a food chain shows multiple chains
c) A food chain includes decomposers, while a food web does not
d) A food web includes primary consumers, while a food chain does not - How do nutrient cycles benefit ecosystems?
a) They ensure the continuous flow of energy
b) They recycle nutrients back into the environment
c) They control population sizes
d) They provide shelter for organisms - Why is it important to understand food webs?
a) To know how energy is transferred and how species are interdependent
b) To learn about different habitats
c) To study individual organisms only
d) To understand climate change effects - How do producers contribute to the food chain?
a) By consuming other organisms
b) By providing food and energy to other organisms
c) By decomposing dead matter
d) By competing with other organisms - What happens to energy as it moves up a food chain?
a) It increases
b) It decreases
c) It stays the same
d) It transforms into different types - How can human activities impact nutrient cycles and food webs?
a) By polluting water sources and destroying habitats
b) By promoting the growth of plants
c) By increasing biodiversity
d) By improving soil quality
Class Activity Discussion:
- Q: What are nutrient cycles and why are they essential for ecosystems?
A: Nutrient cycles are the processes through which nutrients are recycled in the environment and living organisms. They are essential because they ensure that nutrients are continually available for growth and development. - Q: Can you describe a simple food chain and its components?
A: A simple food chain might be: Grass → Grasshopper → Frog → Snake → Hawk. The components include producers (grass), primary consumers (grasshopper), secondary consumers (frog), tertiary consumers (snake), and quaternary consumers (hawk). - Q: How do food webs differ from food chains?
A: Food webs are complex networks of multiple interconnected food chains, while food chains show a linear path of energy flow from one organism to another. - Q: What role do decomposers play in nutrient cycles?
A: Decomposers break down dead plants and animals, returning nutrients to the soil which are then used by producers. - Q: Give an example of how energy flows through a food chain.
A: In a food chain, energy flows from producers (e.g., plants) to primary consumers (e.g., insects) to secondary consumers (e.g., frogs) and so on. - Q: Why are food webs important for understanding ecosystems?
A: Food webs are important because they show the complex relationships and interactions between different species in an ecosystem, illustrating how energy and nutrients flow through the system. - Q: How do producers and consumers interact in a food chain?
A: Producers provide energy and nutrients to consumers. Consumers eat producers or other consumers to obtain energy. - Q: What is the significance of understanding nutrient cycles?
A: Understanding nutrient cycles helps us recognize the importance of recycling nutrients and maintaining ecosystem health. - Q: How does a disturbance in a food web affect an ecosystem?
A: A disturbance can disrupt the balance of energy and nutrient flow, potentially harming or displacing organisms and affecting the overall ecosystem stability. - Q: What impact can human activities have on food chains and food webs?
A: Human activities such as pollution, deforestation, and habitat destruction can disrupt food chains and food webs, leading to loss of biodiversity and ecosystem imbalance. - Q: How do you interpret a food web diagram?
A: A food web diagram shows various organisms and their feeding relationships. Arrows indicate the direction of energy flow, with producers at the base and various consumers higher up. - Q: Can you explain the carbon cycle briefly?
A: The carbon cycle involves the movement of carbon between the atmosphere, organisms, and the environment. Plants absorb carbon dioxide, animals consume plants, and decomposers break down organic matter, releasing carbon back into the atmosphere. - Q: What is the role of herbivores in a food chain?
A: Herbivores are primary consumers that eat producers (plants) and transfer energy to secondary consumers. - Q: How can we use food web diagrams to study ecosystems?
A: Food web diagrams help us visualize and analyze the complex interactions between species and how changes to one species can impact the entire ecosystem. - Q: Why is it important to maintain balanced nutrient cycles?
A: Balanced nutrient cycles ensure that ecosystems remain healthy and functional, supporting diverse plant and animal life and enabling the proper recycling of essential nutrients.
Evaluation Questions:
- What are the three main types of nutrient cycles in ecosystems?
- Explain how energy flows through a food chain.
- Describe the role of decomposers in nutrient cycles.
- How does a food web differ from a food chain?
- What is the role of producers in a food chain?
- Identify and describe the components of a simple food chain.
- How do food webs illustrate energy flow in an ecosystem?
- What impact do decomposers have on nutrient cycles?
- Why is it important to understand the interactions within a food web?
- Describe a real-world example of a food chain and its components.
- Meaning of Nutrient Cycle in Nature
- The Water Cycle
- Nitrogen Cycle
- Carbon Cycle
- Food Chain
- Food Web
Meaning of Nutrient Cycle in Nature
A nutrient cycle is a repeated circular form of a particular nutrient or element from the environment through one or more organisms and back to the environment. This Nutrient cycle is necessary for the continued existence of some living organisms so that they will not go into extinction. The organisms that are involved in the nutrient circle benefit from the other organisms in the circle that they feed or depend on. The circle is created by nature in such a way that some organisms are the primary producers, which other organisms feed on. Some creatures are scavengers and clean up remnants in the ecosystem. Sun is the major supplier of solar energy in the ecosystem.
Examples of Other Circles in the Ecosystem
Nutrient circle is the constant circulations of nutrients around the ecosystem. Photosynthesis and respiration drive the movement of oxygen and carbon dioxides to become available all the times.
Water cycle.
We use water every day, where does water comes from, water is found almost everywhere in different forms. Water cycle is the continuous movement of water, from land, rivers and oceans to the atmosphere as vapour and from atmosphere back to land and rivers or oceans as rain.
Nitrogen cycle
We eat food rich in protein such as beans, how does the protein content in it forms? The basic chemical in protein is nitrogen compounds. Nitrogen cycle is the constant flow and replacement of nitrogen in the atmosphere and land and how it gets to plants and animals and back to the soil or atmosphere
Carbon cycle
One of the most abundant elements in the environment is carbon. It exists in the atmosphere as carbon iv oxides (CO₂). Carbon cycle is the processes by which plants and animals use carbon iv oxide and return it back to the atmosphere. Plants absorbs CO₂ from the atmosphere during photosynthesis and releases it back during respiration. Animals takes in carbon stored in plants as food and release it out during respiration. Carbon is also released into the atmosphere through the burning of fossil fuel.
Nutrient cycles in the ecosystem
The nutrient cycle is a system where energy and matter flow between living organisms and non-living parts of the environment. This occurs as animals and plants consume, depend or feed on other creatures as nutrients , and these nutrients are then released back into the environment via death and decomposition.
Importance of Nutrient Circles
- It makes it possible for energy and matter to be transfered between organisms
- It maintains the continued existence of living organisms
- It balance the ecosystem
- Nutrient circle makes it possible to change one form of energy to another
- It is a form of storage of elements, nutrients or energy until they will finally be needed
Food chain
Food chain is the inter connection among organisms in the ecosystem as they depend on each other for survival in respect of food and energy transfer.
For example
Sun aids the growth of carrot.
The carrot is eaten by the rabbit
Rabbit is eaten by fox
And the trend continues like that.
Food Web
This is a more complex food relationship among living organisms. It’s just like the spider web, just as the name implies.
Food web is a diagram that shows the multiple connections between the primary producers and consumers in an ecosystem.
For instant, if the habitat of the organisms in terrestrial, then we know that sun is the major supplier of solar energy in the ecosystem.
The green plants like grasses produce their own food in the presence of sunlight. The process whereby green plants manufacture their food in the presence of sunlight is known as photosynthesis.
In the food web, animals like goats, rams, sheep or donkeys feed on the green plants like grasses.
Or at times the green plants may serve as food for insects like crickets, locusts or grasshoppers. That is why it is called food web. Everything in respect of food connection is interwoven and connected just like the spider’s web.
Lizards feed on locusts and spiders
Lizards serves as food for birds like eagles or hawks
Man feed on sheep and goats
Man dies and bacteria helps in decomposition
EVALUATION
- The roles of bacteria in the nutrient Circle is to help with the _______ of Organisms (à) resurrection (b) decomposition (c) purification
- Burning of bush affect the _______ circle of the atmosphere (a) water (b) carbon (c) sun
- A pathway by which nutrients pass from one stage in form or organism to another stage is known as _____________ (a) Photosynthesis (b) caffeinated (c) nutrient Circle
- Write out four importance of food chain
Conclusion:
Summarize the key points of nutrient cycles, food chains, and food webs. Emphasize the importance of each component in maintaining ecosystem balance. Provide feedback on students’ understanding and assign a related activity or homework for further exploration.
Understanding Nutrient Cycles and the Interconnected Web of Life
Nutrient Cycles, Food Chains, and Food Webs
Learn About Nutrient Cycles, Food Chains, and Food Webs for JSS 2
Explore nutrient cycles, food chains, and food webs with this detailed lesson plan for JSS 2 students. Understand how energy and nutrients flow through ecosystems and the roles of different organisms.
This lesson plan aims to provide students with a comprehensive understanding of how nutrients and energy move through ecosystems, enhancing their grasp of ecological relationships and interactions.