Plant Biology and Identification
What the domain covers
This domain tests basic plant structure, function, and identification. Expect questions on roots, stems, leaves, flowers, fruits, monocots versus dicots, photosynthesis, transpiration, and binomial nomenclature.
Core rules and concepts
- A typical plant has roots, stems, leaves, flowers, fruits, and seeds; each organ has vegetative or reproductive functions.
- Monocots usually have fibrous roots, parallel venation, scattered vascular bundles, and flower parts in threes.
- Dicots usually have taproots, reticulate venation, vascular bundles in a ring, and flower parts in fours or fives.
- Photosynthesis converts light, carbon dioxide, and water into carbohydrates and oxygen; respiration releases energy; transpiration cools leaves and pulls water upward.
- Botanical names use binomial nomenclature: genus starts with a capital, species is lower case, and both are italicised or underlined.
- Identify plants using habit, leaf arrangement, leaf margin, venation, inflorescence, flower, and fruit.
Worked example
A plant has fibrous roots, long leaves with parallel veins, and flowers in threes. The reasoned identification is a monocot. The features are consistent across the three organs, so the conclusion is stronger than relying on leaf shape alone. A common name such as “grass” is not enough for a botanical identification.
Traps
- Confusing a leaflet with a whole leaf: look for the bud at the base of the leaf.
- Using flower colour as the main identifier: colour varies within a species.
- Calling a taproot “fibrous” because it is branched.