CCEA A Level Biology 5.7 Kingdom Plantae Exam Questions

About CCEA A Level Biology 5.7 Kingdom Plantae

Section 5.7 of Unit A2 2 looks at evolutionary trends in the plant kingdom through three named groups: mosses, ferns and flowering plants (angiosperms). For each you need to describe and explain features linked to life on land: support, water uptake and transport, water conservation through cuticles and stomata, and the method of dispersal by spores or seeds. The key idea is increasing independence from water and increasing size as vascular tissue and lignified xylem develop. You also need xerophytic adaptations in flowering plants. Practical work uses living and preserved specimens, prepared slides and photographs, so expect to identify features from images.

What you need to know

• Mosses Multicellular plants with no true roots, stems or leaves, no cuticle and no stomata except on spore-producing structures. They are anchored by rhizoids, supported by turgor, absorb water over their surface, disperse by spores and are restricted to moist habitats.
• Ferns Have a vascular system with xylem, true roots, stems and leaves, a waterproof cuticle and stomata that control water loss. Xylem gives support and allows greater height. They still disperse by spores and need water for fertilisation.
• Flowering plants Have extensive lignified xylem and wood for support, well-developed cuticles and stomatal control for water retention, and reproduce by seeds, which protect the embryo and allow dispersal independent of water.
• Xerophytic adaptations Sunken stomata, hairs, rolled leaves, thick cuticles, reduced leaf area, succulent tissue and deep roots reduce water loss or increase water uptake.
• Evolutionary trends From moss to fern to angiosperm, plants show increasing development of vascular tissue, support, waterproofing and control of water loss, and a move from spores to seeds.

Common mistakes in 5.7 Kingdom Plantae

• Saying mosses have roots. They have rhizoids, which anchor the plant but are not true roots with vascular tissue.
• Saying ferns reproduce by seeds. Ferns disperse by spores.
• Saying mosses are small only because they live in damp places. They are small because they lack lignified vascular tissue for support and water transport.
• Listing xerophytic features without explaining them. Link each feature to reduced water loss, for example sunken stomata trap humid air and reduce the water potential gradient.
• Forgetting that the moss cuticle is absent. Water can be absorbed and lost across the whole surface.

Try three 5.7 Kingdom Plantae exam-style questions