Year 1 · Classification · Section 3.4
Plants
Classifying plants
Plants are classified using features such as their chloroplasts, body structure and cell functions. Two groups considered here are green algae and vascular plants.
Vascular plants
Vascular plants have specialised transport tissues and typically have roots, stems and leaves. They reproduce in different ways:
- Seeds: Seed plants include daisies, shrubs and trees. Flowering plants make seeds in flowers; other seed plants, such as conifers, produce seeds in cones.
- Spores: Other vascular plants, including ferns and horsetails, reproduce using spores. A spore is a cell that can grow into a new stage of the plant's life cycle.
Spore-producing plants
Spore-producing plants reproduce using spores rather than seeds and do not produce flowers. Some have true roots, stems and leaves; others have simpler structures.
- Mosses: Small plants with leaf-like structures. Spores form in capsules on stalks above the plants. Mosses are not vascular plants.
- Horsetails: Have hollow, jointed stems. Spores form in special structures at the tips of some stems.
- Ferns: Often have large divided leaves. Spore-producing structures occur in clusters on the undersides of the leaves.
Algae
Algae usually live in water and do not have true roots, stems, leaves or flowers. They absorb dissolved substances from their surroundings. Reproduction varies:
- Some algae reproduce using spores.
- Many unicellular algae reproduce by cell division.
Green algae can be unicellular or multicellular:
- Unicellular: Some green algae form a green coating on trees and walls and reproduce by division.
- Multicellular: Sea lettuce grows in the sea and is edible. Different types of edible seaweed are used in food, including some sushi dishes.
Glossary
- Algae
- A diverse group of relatively simple organisms, usually aquatic, that generally make food using light.
- Green algae
- Algae containing green chlorophyll, closely related to land plants.
- Spores
- Reproductive cells that can disperse and develop into a new stage of an organism's life cycle without fusing with another cell.
- Spore-producing plants
- Plants, such as mosses and ferns, that reproduce using spores rather than seeds.
- Vascular plants
- Plants with specialised tissues transporting water, minerals and sugars.
- Seaweeds
- Multicellular algae living mainly in the sea, without true roots, stems or leaves.
- Seed plants
- Plants that reproduce using seeds.