Chapter 3 — Plant Kingdom

Class 11 Biology Chapter 3 covers the Plant Kingdom, classifying plants into five major groups: Algae, Bryophytes, Pteridophytes, Gymnosperms, and Angiosperms, based on the Whittaker classification system.

Chapter 3 explores the complete classification of Kingdom Plantae. Algae are photosynthetic aquatic organisms divided into Chlorophyceae (green), Phaeophyceae (brown), and Rhodophyceae (red) based on pigments and stored food. Bryophytes, the amphibians of the plant kingdom, include mosses and liverworts and depend on water for sexual reproduction. Pteridophytes are the first terrestrial plants with vascular tissues (xylem and phloem) and include ferns and horsetails. Gymnosperms produce naked seeds with no ovary wall protection. Angiosperms are flowering plants with seeds enclosed in fruits, divided into dicots and monocots.

1. 01Plant Kingdom classification follows Whittaker's Five Kingdom system, now excluding Fungi and members of Monera and Protista that possess cell walls
2. 02Algae reproduce via three methods: vegetative (fragmentation), asexual (zoospores), and sexual (isogamous, anisogamous, or oogamous)
3. 03Bryophytes are called plant kingdom amphibians because they live in soil but require water for sexual reproduction and play crucial roles in plant succession on bare rock/soil
4. 04Pteridophytes are the first terrestrial plants with true vascular tissues (xylem and phloem) and true roots, stems, and leaves; they require water for gamete transfer
5. 05Gymnosperms have naked ovules exposed before and after fertilization, producing true seeds without fruit coverings
6. 06Algae account for at least half the total carbon dioxide fixation on Earth and form the basis of aquatic food chains