How do fungi get their food? What are the implications of this mode for fungal body plans? For fungal ecology?
Fungi ingest food through a process called absorptive nutrition. This means that all organic matter enters the organism through its body surface. Fungi must have a high ratio of surface area to volume for this mechanism of ingestion. Most species achieve this by developing into networks of hyphae, or thin strands one to two cells thick.
Fungi cells are protected by walls made of chitin. Food particles must be small enough to make it through this cell wall, so digestive fluids must be released from the cells onto the food source first. Once the matter has broken down, then it can be absorbed into the fungal cells. This is called external digestion, and it causes fungi to be dependent on physical contact with food sources. Because of this, fungi have also developed the ability to grow rapidly and spread across large areas in search of these resources.