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A food web is a tool that illustrates the feeding relationship among species within a specific habitat. It is a connection of multiple food chains to show the interaction between different organisms in an ecosystem.
When you draw multiple food chains together, you end up with a food web. These represent relationships in ecosystems more accurately and gives you a much clearer visualization of how each animal affects others.
Read on to find out how energy is transferred in a food web!
Food chains and food webs both help us better understand how energy is transferred through an ecosystem. However, food chains and food webs have some big differences.
A food chain presents a unique, connected path of energy flow in an ecosystem, whereas a food web explains how food chains overlap. This means a food chain shows a single pathway from the producers to the consumers and how the energy flows in this pathway.
This is an example of a food chain:
However, there are many overlapping food chains in any ecosystem and most plants and animals are part of several chains. In the example above, a shrew isn't just eaten by foxes, and a fox doesn't only eat shrews — you can only see part of the whole picture.
The food web definition in biology can be explained as a visual representation of all the food chains which are connected in a single ecosystem.
An ecosystem contains living things, that are all part of multiple food chains. All of these food chains are then connected to create a food web. This helps us to visualize the path of energy and nutrients between different living organisms.
Animals don't eat the same food every day and like to interact with various prey, so a food chain alone might not be enough to represent the complexity of our ecosystems. This is where food webs come in! By combining multiple food chains, food webs show you how energy travels all-around a habitat.
It is important to give students food web examples, to visually demonstrate how a food web diagram works.
Within the food web example below, there are a number of individual food chains.
For example:
You'll also notice some animals have more than one source of food. This gives them more options for food if one of the others decreases.
The lion, for example, eats both giraffe and rhino. If one were to become unavailable, it will still have a source of food to survive.
The antelope, however, relies on grass for food. If the environment changed and the amount of grass quickly depleted, the antelope would have to adapt and look elsewhere for food.
Every part of the food web is affected by another part. If the population of a predator were to increase, then the prey's population would decrease. If the population of the prey (assuming it's a herbivore) were to increase, then the number of plants and green vegetation would decrease.
To learn more about ecosystems, check out our Animals and Habitats Matching Activity. This teacher-made resource supports students as they learn about animals and the habitats in which they live. To get started with this activity, simply print the habitat mats and cards, and distribute them to your students to use their fine motor skills to cut out the cards.
Once ready, your students can complete the activity either independently or as a small group. The habitat mats and cards in this resource can also be laminated for many reuses, making them perfect for lessons and activity centres when learning about food chains, food webs, and the Earth’s ecosystems.
This resource addresses the following standards: NGSS K-LS1-1; TEKS Science K.9, 2.10.A.
You could even use an educational video like this one to help explain food webs to your elementary students:
What are the different types of food webs?
There are two main types of food webs. These are a grazing food web and a detrital food web.
A grazing food web begins with photosynthetic plants and algae, known as autotrophs. Autotrophs are organisms that have the ability to use simple inorganic substances like carbon dioxide into nutritional organic substances.
A detrital food web is based on decomposers. Decomposers are organisms that break down, rot and decay organic material. An example of a decomposer is fungi. Learn more about decomposers below.
Trophic levels refer to a level or feeding position that an organism occupies in the food chain or food web. There are five main trophic levels within a food chain, which include the following.
Plants and algae are called producers. They create their own food and energy using sunlight, water and carbon dioxide. This process is called photosynthesis. Producers are at the bottom of the food chain and serve as the foundation for all food chains.
The organisms which eat the producers are called primary consumers. The animals in this group are herbivores. Herbivores are animals that get their energy and nutrients from a diet consisting exclusively of producers such as plants and algae. Some examples of primary consumer animals include sheep, cows, deer, horses and some insects. These organisms occupy the second trophic level in the food chain.
Secondary consumers are organisms that feed on primary consumers. They are usually carnivores and occupy the third trophic level in the food chain.
Tertiary consumers are at the very top of the food chain and often do not have any predators. They can be carnivores that feed on other carnivores or omnivores — organisms that eat other animals or plants.
Decomposers are bacteria and fungi that break down dead or decaying plant and animal matter into chemical nutrients like carbon and nitrogen that are released back into the soil, air, and water. This is consumed again by green plants. Examples of decomposers include fungi, bacteria, earthworms, flies, and maggots. They occupy the very bottom trophic level of the food chain.
Energy is transferred in a food web between trophic levels when one organism eats another. This triggers the transfer of molecules that are rich in energy from the prey’s body. Whilst these energy transfers work, they are pretty inefficient, which limits the length of food chains.
When energy enters a trophic level, a portion of it is stored as biomass in organisms’ bodies. This energy is then available to the next trophic level, as only energy that is stored as biomass can be eaten. Generally speaking, only around 10% of the energy that is stored of biomass in 1 trophic level, per unit time, is stored as biomass in the next trophic level, per the same unit of time.
Let’s break that down with an example. If the primary producers of an ecosystem store 50,000 kcal/m squared/year of energy as biomass, this same amount of energy will be available to the primary consumers, which eat the primary producers. The rule of 10% would suggest that the primary consumers would store only 5,000 kcal/m squared/year of energy in their own bodies. This would make energy available to their predators, the secondary consumers, at a significantly lower rate.
This ineffective pattern of energy transfer limits the length of food chains. As the length is limited, after energy has been passed between a number of trophic levels, typically 3 to 6, the amount of energy is too little to support a population at a higher level.
There are a few many reasons as to why energy transferred in a food web exits between trophic levels. Here are the main reasons:
All habitats have a limited amount of the resources needed by plants and animals to survive. For this reason, plants, and animals are forced to compete with one another from time to time for food, water, space, and mates, in order to survive. Often, this competition between animals leads to fights.
Plants are able to generate their own food through the process of photosynthesis, so they do not have to compete for food. However, plants do engage in some competition for resources like water, space and mineral salts.
In a food web, changes in the population of one organism have an impact on the populations of other organisms. This is known as interdependence.
There are a number of practical applications for food webs; they can be very useful in providing an insight into the way nature works. Here are some of the key functions of a food web:
The primary function of a food web is to describe the feeding relationships amongst species in a community. Within a food web, all of the species can be separated into different groups: basal species (autotrophs, like plants), intermediate species (herbivores and intermediate level carnivores), and top predators (high-level carnivores). These feeding groups are called trophic levels (detailed above in ‘What are Trophic Levels?’ section).
Grouping all of the species into different groups or trophic levels makes food webs simpler and, thus, makes it easier for us to understand the relationships between species.
Simply put, indirect interactions happen when 2 species do not interact with each other directly but influence a 3rd species. There is a range of different ways that species can influence one another.
For instance, the rocky intertidal zone of the Pacific Northwest coast is home to several species of starfish, including starfish, barnacles, limpets, and mussels. A food web of this community was constructed and studied, and the results showed that the starfish preyed on a wide range of invertebrate species. When starfish were removed from this community in the Pacific Northwest coast led to a reduction in the diversity of prey species as there was increased competition.
Some other functions of food webs include:
If you're teaching a lesson about what food webs and food chains are, then Twinkl has plenty of resources to support you and enrich your lessons with elementary students!
Our resources are all teacher-made by our experienced team of educators, Common Core-aligned, and ready for instant download today. Take a look at some of our top suggested resources below to discover time-saving ways to engage your students in learning about animals, food chains, and food webs:
This is a great tool for exploring this science topic with your whole class. Packed with interesting information and engaging features, this informative PowerPoint is the perfect resource to introduce your students to food chains.
By using this resource, students will be provided with information about what a food chain is, why they are important, and a range of exciting interactive questions to keep students engaged. This includes an interactive feature for students to guess as a class what a cow, tiger, lion and shark eats, supported by beautiful illustrations.
Learn about animal diets in food webs using our cut-and-paste activity. This hands-on activity helps students to engage in learning about the diets of different types of animals. To use this resource, students will cut-and-paste omnivores, herbivores, and carnivores onto a Venn diagram to create a visual representation of animal diets.
Once complete, students’ Venn diagrams can be used as part of an engaging display on animals, food chains, and food webs. Alternatively, students can keep their completed diagram in their science folders as a handy reference when learning about life science.
Find out about animal adaptations with our research template to develop an understanding of biology. By downloading this resource, your students will be provided with a structure to record information discovered through their research on animal adaptations.
To complete this activity, students are tasked with choosing an animal adaption to research and record the details of their findings on the graphic organizer. This not only helps to expand your students’ knowledge of animals and their adaptations, but also develops their research and writing skills.
Introduce your students to the seven characteristics of living things with this amazing, illustrated PowerPoint. By using this PowerPoint, you can effortlessly present your students with all the unique characteristics of living things. This includes characteristics such as organization, reproduction, growth, adjustment, adaptation, consumption of nutrients, and excretion of waste. Use this presentation as a whole-class activity when learning about life science, food chains, and food webs.
Increase your students’ knowledge about their surrounding ecosystem with our Earth Day Activity Pack. This downloadable resource is packed full of fun and engaging worksheets, craft projects, colouring pages, maths activities, and more to help your students learn while celebrating Earth Day. Within this download, you will also find a handy Earth Day PowerPoint Presentation, helping you to explain what this important day is all about.
If you enjoyed the resources included in this teaching wiki and would like to know where you can find more, visit our fifth-grade Animal resources. Here you will discover plenty more teacher-made resources to enrich teaching and expand your students’ knowledge of animals and the food web.
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