Kingdom Fungi
The fungi — moulds, mushrooms and yeasts — are eukaryotes with cell walls made of chitin (not cellulose). Most are made of thread-like hyphae that spread as a network, the mycelium. Fungi cannot photosynthesise; they feed by saprotrophic nutrition — secreting enzymes onto their food to digest it outside the body, then absorbing the soluble products. They reproduce by spores.
Fungi matter as decomposers, as food, and in making bread, cheese and antibiotics — though some cause disease or spoil crops.
Kingdom Plantae
The plants are multicellular eukaryotes with cellulose cell walls that make their own food by photosynthesis in chloroplasts. The kingdom ranges from simple non-vascular plants to complex flowering plants, showing increasing adaptation to life on land.
Plant groups
Plants are grouped by their complexity. Bryophytes (mosses) are small and non-vascular, with no true roots or transport tissue, so they need damp places. Ferns have vascular tissue (xylem and phloem) but reproduce by spores. The seed plants reproduce by seeds and dominate the land: conifers bear seeds in cones, while the flowering plants (angiosperms) enclose seeds in fruits and are the most successful group.
| Group | Vascular tissue | Reproduction |
|---|---|---|
| Bryophytes (mosses) | no | spores |
| Ferns | yes | spores |
| Conifers | yes | seeds (in cones) |
| Flowering plants | yes | seeds (in fruits) |
A worked example
Explain why a fungus is placed in its own kingdom rather than with the plants.
- Fungi cannot photosynthesise; plants can.Fungi have no chlorophyll or chloroplasts.
- Fungi feed saprotrophically — digesting food outside and absorbing it.This is a fundamentally different way of feeding from plants.
- Fungal cell walls are made of chitin, not the cellulose of plant walls.A key structural difference.
- These differences place fungi in a separate kingdom.Classification reflects fundamental biology.
Fungi cannot photosynthesise, feed by absorption after external digestion, and have chitin cell walls — all unlike plants — so they form their own kingdom.
Fungi in disease and industry
Fungi touch human life in many ways. Some are pathogens — causing athlete's foot and ringworm in people, and destroying crops (rusts and mildews) — while others spoil stored food. But many are invaluable: yeast ferments to make bread and alcohol; the mould Penicillium gave us the first antibiotic, penicillin; mushrooms are food; and as decomposers fungi recycle nutrients from dead plants and animals just as bacteria do.
How plants conquered the land
The plant groups are really a story of increasing adaptation to life on land. Early plants (mosses) needed damp surroundings and water for reproduction. The key innovations that freed plants from water were a waterproof waxy cuticle (to reduce water loss), vascular tissue (xylem and phloem, to transport water and support tall growth), and finally seeds and pollen (so reproduction no longer needed water). Flowering plants, with all of these plus flowers and fruits, became the most successful land plants.
The march onto land
Cuticle (stops drying out) → vascular tissue (transport and support) → seeds and pollen (reproduce without water). Each innovation let plants live and reproduce further from water.