Level 2+: Decomposers Unit

Have you ever thought about how much decaying matter exists on our planet? And what things would be like without anyone to clean it up? Fortunately, we don’t have to—thanks to decomposers! Decomposers are like the cleaning crew of our planet, and this week we’ll get to know a few of the crew’s most prominent members (while flexing our math, science, and literacy muscles!). Print your skills tracker here and let’s get learning!

Note: Occasionally we include project modifications (which can be useful for including younger siblings) and upgrades (for children ready for more). We’ll mark those with the minus (-) or plus (+) symbols.

What you need:

Books (find at your local library or order below on Amazon):

Additional books:

Supplies (use what you have, but here are links to shop if you need anything):

What to do:

We recommend doing the below lessons in this order to build on each skill your child will develop, but don’t feel that you *need* to do them in this order. Do what works for you and your child. If they love an activity, feel free to repeat! Not a winner? Skip and try the next thing. Have fun!

Phonics Guide:

New to our phonics guide? Start here. The Phonics Guide this week will highlight the TI phonogram.

Lesson 1:

Let’s dive into the (often overlooked) world of the decomposer! The book Rotten!: Vultures, Beetles, Slime, and Nature’s Other Decomposers will be the spine for this week’s unit. Begin by reading the intro and chapters 6-8 (or as much as your child is interested in reading). Then, watch this video for more.

Activity 1: Decomposers play a crucial role in every ecosystem’s food chain. In nature, scientists classify animals by how they obtain energy. They are called producers, consumers, or decomposers.

Producers make their own food, which creates energy for them to grow, reproduce and survive. Being able to make their own food makes them unique; they are the only living things on Earth that can make their own source of food energy. Can your child think of a living thing that makes its own food? (Plants are earth’s producers.)

Consumers are living things that have to hunt, gather, and eat their food. Consumers have to eat to gain energy or they will die. There are four types of consumers: omnivores, carnivores, herbivores, and decomposers. Consumers are predominantly animals.

Decomposers and scavengers break down dead plants and animals. They also break down the waste (poop) of other organisms. Decomposers are very important for any ecosystem. If they weren’t in the ecosystem, the plants would not get essential nutrients and dead matter and waste would pile up.

After talking through these roles with your child, let’s ensure their understanding with a hands-on activity. Label three paper plates or baskets with “producers,” “consumer,” and “decomposer.” Next, print these cards and cut them out. Let your child sort the living creatures into their correct place. Are there any animals that could go into multiple baskets? What other creatures can they think of that could go in these categories?

Activity 2: Next, let’s discuss the role of decomposers in the food chain with a game! Using the same cards, deal each player 4 cards. Have someone start by laying down a producer. (If no one has a producer, draw cards until someone gets one.) Then, the next player needs to cover that card with a consumer that eats that producer. The next player covers that card with a creature that eats that consumer. If the next player can’t cover that creature, they draw a card. The game ends when you reach the end of the food chain and lay down a decomposer or someone runs out of cards.

Activity 3: The truth is, no real terrestrial food chain ever ends—that’s because the work of decomposers actually becomes crucial energy for many producers and consumers. The result is something called detritus, or dead and decaying organic matter that includes fallen leaves, dead plant parts and animals, and much of the work is done by microscopic decomposers. Watch this simple video for a visual breakdown of how it all works. If possible, go on a nature walk in your area and help your child identify items that will break down into detritus. Discuss how these things need help to break down into soil or other matter that can be reused.

Next, create this sandwich bag compost. While large-scale compost bins take months to turn into soil, this small-scale version should convert more quickly, giving your child a visual reference to how microscopic decomposers help clean up waste from the planet.

Lesson 2:

Today, we’ll look at decomposers slightly bigger than the microscopic: beetles! A variety of beetle-like creatures play an important role in breaking down plant and animal matter into something useful, as well as clearing away the earth’s natural garbage. If you haven’t already, you may want to revisit our dung beetle lessons from our Level 2: Insects + Spiders Unit. (Chapter 1 of our Rotten! book also discusses these fascinating insects!) Next, we’ll focus on another important decomposer that looks like an insect, but is actually something else entirely in the book I’m a Pill Bug (or you can read it here on OpenLibrary).

(+) If your child loves bugs, you may also wish to read The Decomposers: The Insects that Run Our World today.

Activity 1: Pillbugs (or roly-polys, as they’re sometimes called) are often favorites of children because of their unique defensive ability to roll themselves into little balls. If you can find them in your area, create a habitat where your child can observe some of their behaviors throughout the week (just don’t forget to gently release them when we’re done!).

You may also wish to conduct a few experiments to determine the likes and dislikes of your pillbugs. For example:

  • Determine if pill bugs prefer damp or dry environments by putting a damp paper towel and a dry paper towel in a deep baking dish. Place your pillbugs in the dish and see where they migrate.
  • Determine which foods your pill bugs prefer by placing dead leaves, fresh leaves, slices of fruit, or other plant matter in the dish and seeing where they crawl first.
  • Determine if your pillbugs prefer dark or light environments by placing the dish in a well-lit spot and adding scrap cardboard or leaves that they could choose to hide under, if desired. After 10-30 minutes, see where most of the pillbugs have crawled.
  • How long does a pillbug stay rolled up? Give them a gentle poke to encourage them to form a ball, and then use a timer to see how long it takes for them to relax. Repeat the experiment 3-4 times and find the average of your times.

What other tests can your child come up with? (Reminder: Only conduct tests that won’t hurt the pillbugs!)

Activity 2: Let’s make a pillbug craft to record some of the facts we’ve learned about these amazing crustaceans. Begin by printing two copies of this template onto dark brown or dark gray paper. Cut out the segments. Use a silver or white pen or pencil to write one pillbug fact on seven of the segments.

To build your pillbug, stack the segments with the blank segment on the top of the pile and the top point of the triangles pointed down. Stick a brad through this point to hold the segments together. Now the pillbug should open and close! Use lighter brown or black paper to create legs (glue them to the first and last segment) and antennae. Finish with a googly eye! It should look something like this:


Activity 3: As we read, pillbugs aren’t actually bugs or insects—they are crustaceans! Crustaceans are a type of invertebrate. Invertebrates are animals without a backbone or bony skeleton. They range in size from microscopic mites and almost invisible flies to giant squid with soccer-ball-size eyes. (source) We learned about vertebrates (or animals with a backbone) in our Level 2+: Australia Unit. Today, we’ll recreate our Animal Detective Game to identify the six main types of invertebrate. First, let’s learn what they are:

  • poriferans: More commonly known as sponges, the phylum name Porifera means pore-bearing. Sponges take their name from small holes that cover their bodies. They live in the water and don’t move around on their own.
  • cnidarians: These are water animals that have a simple, usually symmetrical, body with a mouth opening, including jellyfish, anemones, hydras, corals and polyps. All cnidarians have stinging cells, and many are able to reproduce without mating and by mating. Cnidarians are either bell-shaped and mobile, like the jellyfish, or tubes anchored to one spot, like coral and sea anemones. (source)
  • echinoderms: A group of animals that live in on the ocean floor. Examples of echinoderms include starfish, brittle stars, echinoids, sea cucumbers, and sea lilies. They are grouped together because they all have spiny or bumpy skin, live in the ocean, are invertebrates, and have radial symmetry, or symmetry around a central point. (source)
  • mollusks: A mollusk is a kind of animal with a soft body. Most mollusks have a hard shell that protects the body. There are more than 100,000 species, or types, of mollusk. Octopuses, oysters, snails, and squid are just a few examples. Most live in water, but some live on land and prefer moist places. A mollusk’s soft body has a covering called the mantle. In most kinds of mollusk, the mantle makes a shell. (source)
  • annelids: The animals in the Annelida are segmented worms, like earthworms or leeches. They have no legs, and no hard skeleton. Unlike mollusks, annelid bodies are divided into many little segments, like rings joined together. There are many other kinds of worms, but only annelids are segmented this way. (source)
  • arthropods: The term “arthropod” means “jointed legs.” The phylum included invertebrates with an exoskeleton and jointed legs and lives on land and in the water. Scientists have identified more than a million different types of arthropod, and there may be many more. Insects, crustaceans, and arachnids are three of the largest arthropod groups. The exoskeleton is made of a material called chitin. It is hard and cannot bend. The bodies of most arthropods are therefore jointed at various points to allow them to move. At several times throughout their lives, arthropods form a new exoskeleton and shed the old one. (source)

After sharing this information with your child, print this invertebrate version of our Animal Detective Game. Laminate at least the first page and cut out the animal cards. Give your child the first page and a dry erase marker. Show them an animal card and read the description as they check off information on their checklist. At the end, can they determine which type of invertebrate this animal is? Repeat as many times as your child has interest!

Lesson 3:

One of our favorite decomposers? The earthworm! Let’s learn more about them by reading Wiggling Worms at Work (or you can read it here on OpenLibrary), and/or you can read chapter five in our Rotten! book. If you are learning along with a younger sibling, you may wish to incorporate some activities from our Level 2: Spring Unit, Lesson 3.

Activity 1: Watch this video to learn more bout the might earthworm. Next, print these pages to learn about the worm’s anatomy and get some copywork practice.

Activity 2: Want to observe some real worms this week? Follow these steps to create a wormery, or you could purchase this worm farm.

Activity 3: Ready for a worm race? Follow the instructions in this post to create your paper worms. Add a math element by measuring out a race track on the floor with masking tape before you race. You could also add more measurement by seeing how far a single blow could take your worm, and then calculating how many blows it will take to reach the finish line. Test your math with an actual race!

Activity 4: Finish the day with this cute “worm and dirt” snack, or you can make these glow-in-the-dark gummy worms!

Lesson 4:

Not all decomposers are animals. Today, we’ll take a look at how fungi assists in breaking down the world’s dead and rotting matter. Check out chapter three of our Rotten! book, and/or read Mushroom Rain.

For younger children, don’t miss Lesson 2 of our Level 2: Forest Unit. You can also learn more about fungi in our Level 2+: Germs, Viruses + Fungi Unit.

Activity 1: Most fungi are decomposers called saprotrophs. They feed on decaying organic matter and return nutrients to the soil for plants to use. Fungi are the only decomposers that can break down wood and the cellulose in plant cell walls, so they are the primary decomposers in forests. (source) Let’s learn more about how they do this in this video.

Fungi are critical parts of most ecosystems and an important part of the diet of many students (and teachers). Mushrooms in the genus Agaricus are raised commercially and sold in most grocery stores. The mushroom is actually the fruiting body or reproductive structure of a fungus. Print these pages for a visual reminder of the mushroom anatomy and life cycle. (You may already have them from a past unit. If so, you can decide with your child if they want to do the copywork or skip it.)

Let’s dissect a mushroom to become more familiar with it’s parts. You will need a mushroom (preferably one with the stem still attached—we recommend a mushroom from the grocery store to ensure it is safe to touch), a knife, tweezers (optional), paper towel, magnifying glass (optional).

Get your mushroom and place it on a plate or cutting board in front of you. Examine it closely. On a separate sheet of paper or in your nature journal, draw a diagram of your mushroom, labeling the cap, stem and gills. If the gills are not visible, remove the tissue (it’s called a veil) protecting them gently with your tweezers.

Grasp the cap firmly with one hand and the stem with the other hand. Gently wiggle and/ or twist the stalk until it breaks away from the cap. Pinch the stalk between your fingers until it breaks into two or more long pieces. Gently pull the pieces apart. The thin, hair-like filaments you will see where you split the stem are the hyphae. What do they look like? Draw and describe them.

Finally, turn your attention to the cap. Look at the underside of the cap to study the gills. Each gill is lined with thousands of small structures called basidia. Using your forceps, you can gently remove one gill from the cap. What do the gills remind you of? Draw them on your page. (source)

Activity 2: Mold is a fungi that your child is likely familiar with. Let’s grow some of our own in a “mold terrarium” so we can see how it breaks down plant matter.

Print these pages for your child’s observations. You may only need the first sheet, or you can use multiple copies of the second page to record observations from additional days.

Begin with a large zippered plastic bag and a paper or plastic plate. On the plate, arrange a few pieces of plant-based food, such as a piece of bread, fruit, crackers, etc. (Do NOT use animal-based foods.) Place the plate inside the bag and seal completely.

On the days indicated on your child’s observation sheet, have them draw what they see. Which foods mold the fastest? Why do they think that happens? When you are done with the experiment, do not open the bag–this could release spores that can be harmful. Instead, throw the entire experiment away while sealed.

(+) Want an upgrade? Create two or three versions of your terrarium, but change the conditions for all but one of them. For example, you might place the food on a damp paper towel in one or expose one terrarium to more heat. Print multiple observation sheets and record how these changes affect the mold growth.

Activity 3: One incredibly ability of fungi that we can read about in Rotten! is its ability to eat pollution. Mycologists (or scientists who study fungi) have found that some fungus can even break down diesel-contaminated soil, reverting these “brownfields” into thriving “greenfields” again. Scientists and engineers are using information like this to repair polluted ecosystems in a process called bioremediation. Let’s break down that word: “Bio” is the study of life. What word does “remediation” sound close to? Remedy is a treatment or cure that corrects something that is wrong or makes you sick. So, bioremediation is basically fixing something that is wrong by using living things. Bioremediation uses decomposers and green plants to return the environment that has been damaged by contaminants or pollution back to its original, healthy state. (source)

Not only is bioremediation a great cause for scientists and engineers to focus on, it’s also a great example of our phonogram this week! Let’s practice some more TI words. Begin by printing these mushroom caps and cutting them out (you may wish to print them on cardstock or thicker paper). On the back of each mushroom cap, write a TI word—we’ve provided a few options below:

  • potion
  • martian
  • patience
  • nation
  • action
  • cautious
  • patient
  • intention
  • mention
  • motion
  • section
  • direction
  • initial
  • information
  • partial

Present them each to your child face down and have them turn over the caps to discover each word. If they read it correctly, they get to keep the mushroom. If not, have them try again or flip it back over to try again later.

Lesson 5:

For our last day of activities, we’ll take a closer look at a special group of decomposers called scavengers. A scavenger is an organism that mostly consumes decaying biomass, such as meat or rotting plant material. Many scavengers are a type of carnivore. Let’s learn about some of the most famous scavengers in (+) Death Eaters: Meet Nature’s Scavengers OR (-) The Ugly Five.

Activity 1: One of our favorite flying scavenger has to be the vulture. Let’s learn a bit more about how they help clean up their environment in this video. Next, let’s bring the vulture’s unique flying ability to life by building this balancing vulture craft.

Activity 2: Our next scavenger is actually a mix of a predator and a scavenger—the hyena! Let’s learn the fact about this carnivore in this video. Next, make this hyena puppet craft.

Activity 3: One more scavenger you might even have in your own backyard? The raccoon! Let’s learn about these masked scavengers in this video.

Raccoons are also famous for scavenging from people! Let’s use that as inspiration for our math activity. Print these pages, cutting out the foods and cutting along the line on the raccoon’s math. (You may want to print more than one of the second page.)

On the food cards, write addition or subtraction problems that your child is ready to work on. Shuffle the food cards in a bowl or bag and let your child draw one at a time. After they solve the problem, let them feed it to the raccoon!

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Published by The Learn + Live Letter

The Learn + Live Letter is a play- and project-based homeschool curriculum for children ages 3-12.