Food Chains 

How does a snail get its food? How about a tree? This activity will teach students about the food chain and why it is important.

All living organisms depend on one another for food. By reviewing the relationships of organisms that feed on one another, this lesson explores how all organisms— including humans—are linked. If students understand the relationships in a simple food chain, they will better understand the importance and sensitivity of these connections, and why changes to one part of the food chain almost always impact another.

Grade level: 4-8 grades

'What is the greatest sign of success for a teacher transformed? It is to be able to say, 'The children are now working as if I did not exist.' ' Maria Montessori. Food Chains The source of all food is the activity of autotrophs, mainly photosynthesis by plants. They are called producers because only they can manufacture food from inorganic raw materials. This food feeds herbivores, called primary consumers. Carnivores that feed on herbivores are called secondary consumers. Money evaluated 25 of the biggest fast food chains in the U.S.—brands that had over 300 locations nationwide and offered combo meals. Using sample menus on Ownthemeal.com, Money calculated the average cost of a combo meal (defined as entree, side dish and drink).

Performance Expectations:

• MS-LS2-1 Ecosystems: Interactions, Energy and Dynamics. Analyze and interpret data to provide evidence for the effects of resource availability on organisms and populations of organisms in an ecosystem.
• MS-LS2-2 Ecosystems: Interactions, Energy and Dynamics. Construct an explanation about how the different parts of the food chain are dependent on each other.
• MS-LS2-3 Ecosystems: Interactions, Energy and Dynamics. Develop a model to describe the cycling of matter and flow of energy among living parts of the food chain.
• MS-LS2-4 Ecosystems: Interactions, Energy and Dynamics. Construct an argument, supported by evidence gathered through observation and experience, showing how changes to physical or biological components of an ecosystem affect populations.
• MS-LS2-5 Ecosystems: Interactions, Energy and Dynamics. Evaluate competing design solutions for maintaining biodiversity and ecosystem services.
• MS-ESS3-3 Earth and Human Activity. Answer questions about how pollution affects food chains by applying scientific principles to design a monitoring plan for minimizing the human impact on the environment.

For alignment, see: Food Chains and Webs NGSS Summary

Lesson Objectives

• Describe the difference between herbivores, carnivores and producers.
• Answer questions about the interdependence of herbivores, carnivores and producers as members of a food chain.
• Answer questions about how pollution affects food chains.

Background

A food chainis a simplified way to show the relationship of organisms that feed on each other. It's helpful to classify animals in a simple food chain by what they eat, or where they get their energy.

Green plants, called producers, form the basis of the aquatic food chain. They get their energy from the sun and make their own food through photosynthesis. In the Great Lakes, producers can be microscopic phytoplankton (plant plankton), algae, aquatic plants like Elodea, or plants like cattails that emerge from the water's surface.

Herbivores, such as ducks, small fish and many species of zooplankton (animal plankton) eat plants. Carnivores (meat eaters) eat other animals and can be small (e.g., frog) or large (e.g., lake trout). Omnivores are animals (including humans) that eat both plants and animals. Each is an important part of the food chain.

In reality, food chains overlap at many points — because animals often feed on multiple species — forming complex food webs. Food web diagrams depict all feeding interactions among species in real communities. These complex diagrams often appear as intricate spider webs connecting the species.

This lesson demonstrates that changes in one part of a food chain or web may affect other parts, resulting in impacts on carnivores, herbivores, and eventually on producers. An example of this might be the harmful effects of pollution. The point that should be made is that when something disrupts a food web, humans should try to understand and minimize the disturbance. Students should also come to recognize that humans, too, are part of this complex web of life.

Food Chains and Food Webs – Parts and Pieces

Food Chains

• Producers
  Plants form the base of Great Lakes food chains. They're called producers, because they make their own food by converting sunlight through photosynthesis. They also act as food, providing energy for other organisms. In the Great Lakes, most producers are phytoplankton, or microscopic floating plants. An example of phytoplankton is green algae. Large rooted plants, another type of producer, provide food and shelter for different organisms, fish and wildlife.
• Primary Consumers
  The next level in the food chain is made up of primary consumers, or organisms that eat food produced by other organisms. Examples of primary consumers include zooplankton, ducks, tadpoles, mayfly nymphs and small crustaceans.
  
• Secondary Consumers
  Secondary consumers make up the third level of the food chain. Secondary consumers feed on smaller, plant-eating animals (primary consumers). Examples of secondary consumers include bluegill, small fish, crayfish and frogs.
• Top Predators
  Top predators are at the top of the food chain. Top predators eat plants, primary consumers and/or secondary consumers. They can be carnivores or omnivores. Top predators typically sit atop the food chain without predators of their own. Examples include fish such as lake trout, walleye, pike and bass, birds such as herons, gulls and red tailed hawks, bears—and humans!
• Food Webs
  In reality, many different food chains interact to form complex food webs. This complexity may help to ensure a species' survival in nature. If one organism in a chain becomes scarce, another may be able to assume its role. In general, the diversity of organisms that do similar things provides a type of safety, and may allow an ecological community to continue to function in a similar way, even when one species becomes scarce. However, some changes in one part of the food web may have effects at various trophic levels, or any of the feeding levels that energy passes through as it continues through the ecosystem.

At the base of the aquatic food web are:

• Plankton
  Plankton are microscopic plants and animals whose movements are largely dependent upon currents. Plankton are the foundation of the aquatic food web. Plankton are vital in the food supplies of fish, aquatic birds, reptiles, amphibians and mammals.
  
• Phytoplankton
  Plant plankton are called phytoplankton and may be single cells or colonies. Several environmental factors influence the growth of phytoplankton: temperature, sunlight, the availability of organic or inorganic nutrients, and predation by herbivores (plant eaters).
  
• Zooplankton
  Animal plankton are called zooplankton. Zooplankton can move on their own, but their movement is overpowered by currents. Zooplankton may be herbivores or plant-eaters (eat phytoplankton), carnivores or meat eaters (eat other zooplankton) or omnivores, which eat both plants and animals (eat phytoplankton and zooplankton).

Assessment & Standards

See separate document: Lesson Assessment, State of Michigan Content Expectations and National Benchmarks (PDF)

Activity

• Linking the Chain
  Summary: Students work with paper cutouts to learn about the parts of a food chain, specifically herbivores, carnivores and producers.
  Time: 30-60 minutes of class time

This lesson talks about food chains and food webs in our environment.

Food Chains

A food chain is a flow of energy from a green plant (producer) to an animal (consumer) and to another animal (another consumer) and so on. In this lesson we are going to talk all about food chains and food webs in the environment.

All organisms need energy to live. Energy is obtained from food. Green plants are the only organisms that can capture energy from sunlight and make their own food.

Try Food Chains Quiz 1 and Food Chains Quiz 2 at the end of the lesson to check your knowledge about food chains and food webs.

A green plant should always be the first link of a food chain. Green plants are the only organisms that can directly get the sun's energy and make their own food through a process called photosynthesis.

Green plants are the best producers in the environment

Herbivores are animals that only feed on plants.

Omnivores are animals that eat a variety of food of both plant and animal origin.

Carnivores and Top Predators in food chains

Carnivores are animals that only feed on other animals.

Carnivores are also known as the top predators as they are at the highest point of the food chain. Top predators have a little or no enemies. They usually consume all lower levels and are not consumed by any other animals until they die.

Fast-food Chains

Lions, tigers, crocodiles, eagles are the best examples of top predators.

Prey

Prey is an animal that a predator feeds on. For example, a lion feeds on a zebra. So, the zebra is the prey of the lion.

All animals depend on plants directly or indirectly for food and energy.

A chart that shows direct and indirect consumers

Primary Consumers in food chains

Primary consumers are the second link of a food chain. They are usually herbivoresthat eat green plants or sometime omnivoresthat eat both plants and animals.

Let's look at some types of food chain in the examples below.

The green plants are the food of all herbivores that are primary consumers.

Example of a food chain with two links showing the producer and the primary consumer

Secondary Consumers in food chains

Secondary consumers are the third link of a food chain. They can be either omnivoresor carnivores.

The herbivores are the food for carnivores that are secondary, tertiary or quaternary consumers.

Example of a food chain with three links showing the producer, the primary consumer and the secondary consumer

Tertiary and Quaternary Consumers in food chains

Tertiary consumers are the fourth link of a food chain while quaternary consumers are the fifth link of a food chain. They are usually the carnivores that are top predators.

Secondary consumers are the food for carnivores or top predators that are tertiary or quaternary consumers.

Sometimes tertiary consumers can be the food for quaternary consumers.

Likewise, step by step, the energy in food flows from the producers to consumers.

This lesson talks about food chains and food webs in our environment.

Food Chains

A food chain is a flow of energy from a green plant (producer) to an animal (consumer) and to another animal (another consumer) and so on. In this lesson we are going to talk all about food chains and food webs in the environment.

All organisms need energy to live. Energy is obtained from food. Green plants are the only organisms that can capture energy from sunlight and make their own food.

Try Food Chains Quiz 1 and Food Chains Quiz 2 at the end of the lesson to check your knowledge about food chains and food webs.

A green plant should always be the first link of a food chain. Green plants are the only organisms that can directly get the sun's energy and make their own food through a process called photosynthesis.

Green plants are the best producers in the environment

Herbivores are animals that only feed on plants.

Omnivores are animals that eat a variety of food of both plant and animal origin.

Carnivores and Top Predators in food chains

Carnivores are animals that only feed on other animals.

Carnivores are also known as the top predators as they are at the highest point of the food chain. Top predators have a little or no enemies. They usually consume all lower levels and are not consumed by any other animals until they die.

Fast-food Chains

Lions, tigers, crocodiles, eagles are the best examples of top predators.

Prey

Prey is an animal that a predator feeds on. For example, a lion feeds on a zebra. So, the zebra is the prey of the lion.

All animals depend on plants directly or indirectly for food and energy.

A chart that shows direct and indirect consumers

Primary Consumers in food chains

Primary consumers are the second link of a food chain. They are usually herbivoresthat eat green plants or sometime omnivoresthat eat both plants and animals.

Let's look at some types of food chain in the examples below.

The green plants are the food of all herbivores that are primary consumers.

Example of a food chain with two links showing the producer and the primary consumer

Secondary Consumers in food chains

Secondary consumers are the third link of a food chain. They can be either omnivoresor carnivores.

The herbivores are the food for carnivores that are secondary, tertiary or quaternary consumers.

Example of a food chain with three links showing the producer, the primary consumer and the secondary consumer

Tertiary and Quaternary Consumers in food chains

Tertiary consumers are the fourth link of a food chain while quaternary consumers are the fifth link of a food chain. They are usually the carnivores that are top predators.

Secondary consumers are the food for carnivores or top predators that are tertiary or quaternary consumers.

Sometimes tertiary consumers can be the food for quaternary consumers.

Likewise, step by step, the energy in food flows from the producers to consumers.

Scavengers and decomposers in food chains

When an organism dies, it is eventually eaten by scavengers and broken down by decomposers like bacteria and fungi, and the exchange of energy continues in the environment.

Pictures Of Food Chains

• Crows
• Vultures
• Hyenas
• Ants
• Worms
• Crabs

Crows, vultures and hyenas are the best examples of vertebrate scavengers while ants are good invertebrate scavengers in the environment. They eat dead bodies of animals and plants.

Facts About Food Chains

Example of a crow who is a best scavenger in the environment

Bacteria, fungi, algae, lichens are the best examples of decomposers. They break down dead bodies of plants and animals and let the essential nutrients in the dead matter mix with the ecosystem again, so that no waste would pile up.

A food chain is a flow of energy from a green plant (producer) to an animal (consumer) and to another animal (another consumer) and so on.

• A food chain shows us a series of living things that depend on each other for food energy.
• A food chain shows us the relationship between the animals and plants in a habitat.
• A food chain shows us the way energy flows through a habitat.

• There are usually three or four organisms in a food chain:

Each of these organisms in a food chain is called a link. These links make a food chain.

• Food chains usually start with a producer or a green plant :

This is the link where energy from the sun enters the food chain.

Examples of Food Chains Diagrams

In nature the food chains are not as direct as we've seen them in our discussion. The food chains are highly cross linked (connected) and highly complicated. In any habitat there may be many kinds of animals that feed on the same plants and there may be many predators that feed on the same kinds of prey. Therefore there will be several food chains in any habitat. These food chains are inter-linked and they form food networks in the habitat.

Examples Of Food Chains

A food web is a type of a food network with several inter-linked food chains in a habitat.

Food Chains For Kids

Food Web Diagram

Food Webs

Try Food Chains Quiz 1 and Food Chains Quiz 2