Concept preview

What you will be able to do

1. 01Describe how fungi reproduce asexually by budding, fragmentation and spores.
2. 02Explain the fungal sexual cycle: plasmogamy, the dikaryon, karyogamy and meiosis.
3. 03Explain how spores are dispersed and why fungi make so many.
4. 04Outline the three main groups of fungi (zygomycetes, ascomycetes, basidiomycetes).

Almost everything a fungus does about reproduction comes down to one tiny object: the spore. A spore is a single reproductive cell, usually just a few thousandths of a millimetre across, wrapped in a tough protective wall and capable of growing into a whole new mycelium if it lands somewhere suitable. Spores are to fungi roughly what seeds are to plants, but they are far smaller, far more numerous, and much simpler in construction — a spore is essentially a survival capsule containing a nucleus and a little cytoplasm, with no stored embryo. Fungi make spores in staggering quantities: a single large mushroom can release billions of spores over a few days, and a giant puffball may hold trillions. This flood of spores is a gamble played on a vast scale. The overwhelming majority will land on ground that is too dry, too cold, already occupied, or otherwise hopeless, and will simply die. But because the spores are so light and so numerous, at least a few are almost certain to drift onto exactly the damp, nutrient-rich spot where a new fungus can take hold. This is why the air you breathe, indoors and out, is never entirely free of fungal spores — they are one of the most abundant biological particles on Earth.