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Decomposition Facts & Worksheets

Decomposition refers to the process of an organic material undergoing decay. Decomposition is a vital process in the life cycle of any living thing and takes place once the living thing dies.

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Decomposition refers to the process of an organic material undergoing decay. What makes material organic is that it contains carbon. The organic matter breaks down into tiny pieces that are inorganic or organic. Decomposition is a vital process in the life cycle of any living thing and takes place once the living thing dies. The byproducts of decomposition are simple molecules, such as water and carbon dioxide.

See the fact file below for more information on Decomposition, or you can download our 28-page Decomposition worksheet pack to utilize within the classroom or home environment.

Key Facts & Information

TERMINOLOGY

  • Decomposition is the breakdown of organic matter and structures, which results in the recycling of nutrients back into the soil.
  • Organisms that help decompose materials are known as decomposers or detritivores.
  • These decomposers, such as bacteria and fungi, help decomposition by feeding on dead organisms.
  • Taphonomy is the study of decomposition and the processes involved in decay and fossilization.
  • Taphonomy derives from the Greek term “taphos,” which means “tomb.” 
  • The raw materials, such as dead animals and plants, are called detritus. 
  • Saprophytes are microorganisms that live on and process the detritus.
  • Abiotic decomposition occurs when physical or chemical processes break down organic material.
  • Biotic decomposition, also called biodegradation, happens when organic material gets broken down by the metabolism of microorganisms.
  • Water and carbon dioxide are the ultimate products of decomposition.

DECOMPOSING ORGANISMS

  • Detritivores are animals that feed on dead organic matter, particularly plant detritus.
  • Slugs, snails, earthworms, millipedes, woodlice, springtails, and insects like flies, beetles, and their respective larvae are considered detritivores.
  • Mites, carrion beetles, and other arthropods like flesh flies and blowflies are also involved in decomposition processes.
  • Scavengers, including vultures, crows, rats, coyotes, wolves, foxes, and dogs, contribute to the consumption and breakdown of dead animals and waste.

CHEMICAL DECOMPOSERS

  • Unlike decomposing organisms, chemical decomposers are microorganisms that can only be seen and studied closely with a microscope.
  • Bacteria, fungi, and protozoa are considered chemical decomposers.
  • Bacteria are the most abundant and nutritionally diverse of them.
  • Bacteria found in a compost pile are heterotrophic, which means that they feed on other plant or animal matter for nutrients and energy.
  • On the other hand, most fungi are saprotrophic, meaning they eat dead organic matter called detritus, then return nutrients to the soil for plants to benefit from. 
  • Fungi are the main decomposers in forests because they are the only decomposers that can break down wood and the cellulose in plant cell walls.
  • Heterotrophic protozoa are single-celled organisms that speed up the process of decomposition in soils by increasing bacterial growth.

STAGES OF CHEMICAL DECOMPOSITION

  • The two main stages in chemical decomposition are autolysis, which is the breakdown of cells and tissues by their own enzymes; and putrefaction, which is the decay of animal matter by bacteria. 
  • Unlike animal flesh, plant matter decays largely due to fungi, not bacteria.
  • Putrefying animal tissues give off a foul odor which is produced by the release of compounds cadaverine and putrescine.

PHASES OF DECOMPOSITION

  • The first step of decomposition is fragmentation which refers to detritivores breaking down detritus into smaller pieces.
  • The next one is leaching, a process involving water-soluble and inorganic nutrients in the fragmented particles getting dissolved in water and then seeping into the soil before it precipitates.
  • Decomposition continues through catabolism, in which complex molecules are further broken down into simpler inorganic compounds by bacterial and fungal enzymes.
  • Humification follows catabolism; it is the process of forming humus, a dark, organic layer of an amorphous substance that forms in soil when plant and animal matter decays. 
  • Humus is nutrient-rich and makes the soil very fertile.
  • The last phase of decomposition is mineralization, where the humus degrades, and inorganic nutrients are released back into the soil.

STAGES OF HUMAN AND ANIMAL DECOMPOSITION

  • The process of decomposition in humans and vertebrate animals includes five general stages: fresh, bloat, active decay, advanced decay, and dry remains.
  • Fresh is the stage that starts right at the moment when the animal’s heart stops beating, which then halts the blood supply of oxygen and the removal of carbon dioxide from the tissues.
  • Bloat is the stage wherein leaked enzymes from the fresh stage begin the accumulation of gases within the bodily cavity, causing the animal’s size to double and bloat. 
  • The third stage is called active decay, where most body mass is lost because bacteria and insects feed on the dead material.
  • Decomposition fluids are also purged into the environment.
  • Maggots leaving the body mark the end of the active decay stage.
  • During the advanced decay stage, harder tissues like bones, cartilage, and hair are left, attracting insects, beetles, and flies to the body.
  • The dry remains stage follows, which is the period of all byproducts of decomposition drying up, and only the skeletal parts are left.

RATE OF DECOMPOSITION

  • Depending on a body’s exposure to air and water, the rate at which it decomposes varies.
  • Simply put, the greater the exposure to air and water, the faster the decomposition because there will be more chemical decomposers present. 
  • Decomposition also speeds up in warmer temperatures.

FACTORS AFFECTING DECOMPOSITION

  • Factors that affect decomposition include temperature, moisture, soil quality and pH, aeration, litter quality, and inorganic chemicals.
  • Temperature is a vital component that manages the growth, activity, and diversity of decomposing microorganisms.
  • Moisture, or the water present in the soil, also affects the presence of microorganisms.
  • If the soil is wet, decomposition takes longer because too much water deprives the microorganisms of oxygen.
  • The pH of the soil relies on the presence of cations (positively charged ions) and anions (negatively charged ions), which also affect microbial activity.
  • A rich amount of oxygen is also an important factor in supporting aerobic microbial growth.
  • The structural and chemical properties of litter can affect the speed of decomposition. 
  • Inorganic elements, such as calcium, magnesium, potassium, and sodium, are released into the soil after decomposition; some of these are utilized by microorganisms.

FOOD DECOMPOSITION

  • Spoilage is the term used to refer to the decomposition of food — both plants and animals.
  • Spoilage occurs when food is contaminated due to the presence of bacteria, mold, or yeast.
  • Food also undergoes natural decay.
  • Spoiled food cannot be consumed as it may result in sickness.
  • To prevent spoilage, the correct preservation techniques must be applied to food.

Decomposition Worksheets

This fantastic bundle includes everything you need to know about Decomposition across 28 in-depth pages. These ready-to-use worksheets are perfect for teaching kids about Decomposition. Decomposition is a vital process in the life cycle of any living thing and takes place once the living thing dies.

Complete List of Included Worksheets

Below is a list of all the worksheets included in this document.

  1. Decomposition Facts
  2. Vocabulary Review
  3. Unlike the Other
  4. Picture Clues
  5. Fact or False?
  6. Decomposing or Not?
  7. Search and Sketch
  8. Spoiler Alert
  9. Step by Step
  10. Knowledge Recap
  11. Personal Experience

Frequently Asked Questions

What is decomposition?

Decomposition is a natural process by which organic material is broken down into simpler substances. It involves the breakdown of complex molecules into smaller, more basic compounds through the actions of microorganisms, such as bacteria and fungi.

What are the key factors that influence decomposition?

Several factors influence the rate and efficiency of decomposition, including temperature, moisture, oxygen availability, nutrient content, and the presence of decomposers. These factors can vary depending on the environment, and optimal conditions for decomposition differ for different types of organic matter.

Why is decomposition important in ecosystems?

Decomposition plays a vital role in recycling nutrients in ecosystems. It breaks down dead organic matter, such as fallen leaves, dead animals, and plant debris, into simpler compounds that can be absorbed by plants and reused in the food chain. Without decomposition, essential nutrients would remain locked in dead material and unavailable to other organisms.

What are some examples of decomposers?

Decomposers are organisms that break down organic matter. Common examples include bacteria, fungi, worms, insects, and certain species of beetles. These organisms secrete enzymes that break down complex molecules into simpler forms, facilitating the decomposition process.

What are the different stages of decomposition?

  1. The decomposition process typically occurs in several stages:

a) Fresh stage: Immediately after death, the body or organic material is fresh, and decomposition has not yet begun in earnest.

b) Bloat stage: Gases produced by bacteria cause the body or material to bloat and swell.

c) Active decay stage: In this stage, decomposition is at its peak, with a rapid breakdown of tissues and the release of strong odors.

d) Advanced decay stage: The body or material begins to dry out, and decomposition slows down. Fewer insects and scavengers are attracted to the remains.

e) Dry/remains stage: In this final stage, very little organic material remains, and decomposition is minimal.

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Use With Any Curriculum

These worksheets have been specifically designed for use with any international curriculum. You can use these worksheets as-is, or edit them using Google Slides to make them more specific to your own student ability levels and curriculum standards.

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