This definitions covers Key Definitions within Decomposition for GCSE Biology. Topic 4: Decomposition It is section 7 of 12 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
Topic position
Section 7 of 12
Practice
15 questions
Recall
20 flashcards
Key Definitions
Decomposition: The breakdown of dead organic material into simpler inorganic substances (CO2, water, mineral ions) by the action of decomposers.
Decomposer: An organism (bacterium or fungus) that breaks down dead organic material by secreting enzymes externally (saprotrophic nutrition), absorbing the soluble products, and returning mineral ions to the soil.
Detritus feeder (detritivore): An animal (e.g., earthworm, woodlouse) that feeds on dead organic material (detritus), breaking it into smaller pieces and increasing the surface area available for decomposers.
Compost: Decomposed organic material (food waste, plant matter) that has been broken down by decomposers under warm, moist, aerobic conditions — used as a nutrient-rich soil improver.
Biogas: A mixture of gases (mainly methane and CO2) produced by anaerobic decomposition of organic material by bacteria in the absence of oxygen; used as a fuel.
Saprotrophic nutrition: A feeding method used by fungi and some bacteria in which enzymes are secreted externally onto dead organic material, which is digested outside the organism and the soluble products are then absorbed.