☰ Contents · Biology

Higher plants

Lessons 16 · 1 lessons · O‘. Pratov, A. To‘xtayev, F. Azimova, Z. Tillayeva. Biology, Grade 5. Revised and expanded 5th edition. “O‘zbekiston” publishing house, Tashkent, 2020
16

Higher plants

Textbook: pp. 43–49
GoalDivide higher plants into spore plants (moss, horsetail, fern) and seed plants (gymnosperms, angiosperms) and explain the features and importance of each.
New words
spore · sporacone (of gymnosperms) · qubbagymnosperm, seeds lie open on the cone scales · ochiq urug‘liangiosperm, flowering plant with seeds inside a fruit · yopiq urug‘li
Explanation

The body of higher plants consists of root, stem and leaf (mosses have no true roots; they attach with rhizoids). They are divided into spore plants and seed plants. Spore plants include mosses, horsetails and ferns. Mosses (for example Funaria) grow in damp places and their spores ripen in a capsule. The field horsetail has a rhizome; in early spring a brown spore-bearing shoot grows, and in summer a green shoot that photosynthesises. In ferns the spores ripen in sori on the underside of the leaf; in the distant past tree ferns were widespread, and coal formed from their remains. Seed plants reproduce by seeds. In gymnosperms (juniper, pine, spruce, cypress) the seeds ripen openly in a cone, pollen travels by wind, and they give off resin and phytoncides (the resin of ancient trees hardened over millions of years into amber). Pine has needle-like leaves and reaches 30–40 m; juniper grows slowly, lives long and protects mountain slopes from erosion. Angiosperms (apricot, poplar, pomegranate, dandelion, wheat) form flowers, and their seeds are protected inside a fruit; they are the youngest and most widespread group. Angiosperms are divided into monocotyledons and dicotyledons.

Worked examples
A pine cone closes its scales in damp air and opens them in dry air – then winged seeds fly off on the wind. You can watch a cone at home in dry and damp conditions.
If a fern leaf has brown bumps – sori – on its underside, the plant reproduces by spores, not flowers.
Class activity

Table: “Higher plants” – columns: moss, horsetail, fern, gymnosperms, angiosperms; rows: reproductive structure, example, key feature. Take a fallen pine cone and watch how its scales change in damp and dry conditions. Safety: do not taste any fruit or seed in the woods or garden (for example juniper “berries”); if resin sticks to your hands, an adult helps wash it off with soap and vegetable oil.

Practice
1
Which is not a spore plant: Funaria, field horsetail, fern, pine? Explain your answer.
2
Where do the seeds of gymnosperms ripen and how is pollen spread?
3
How can a moss and a fern be told apart?
4
Why are angiosperms the most widespread today?