Grades 3–5 · Organisms
How does a fungal mycelium take in nutrients?
A fungus feeding on a fallen leaf does not need to swallow the leaf. It can break food down outside its body and take in the smaller products. Many fungi spread through their surroundings as a network called a mycelium. Each fine thread in the network is a hypha.
In the diagramFungal threads digest outside, absorb inwardHyphae networkMyceliumOrganic materialEnzymes outProducts inBreakdown outside and absorption inside are distinct.
A thread can release enzymes into nearby dead material. Enzymes are substances that speed particular chemical changes. They help break large molecules into smaller ones. This is digestion, but it happens around the fungal threads rather than inside a stomach.
Small breakdown products can then cross the thread's outer boundary and enter the fungus. Two different journeys are involved: enzymes move outward to work on the material, while usable products move inward to supply the fungus. A large leaf piece does not have to fit through the boundary.
As the network spreads, its many threads place absorbing surfaces close to more material. The fungus can use absorbed substances to support its life and growth. A familiar mushroom is therefore not a mouth eating the leaf; the much less obvious network can do the feeding. This describes one fungus living on dead material, while other fungi have different partnerships and food sources.
About this explanation
Starting knowledge: Know that living things use nutrients and that large material can be broken into smaller parts.
Sources
- OpenStax, Rice University — 24.1 Characteristics of Fungi
- OpenStax, Rice University — 24.3 Ecology of Fungi